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  Subjects -> ENGINEERING (Total: 2282 journals)
    - CHEMICAL ENGINEERING (192 journals)
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    - ELECTRICAL ENGINEERING (102 journals)
    - ENGINEERING (1204 journals)
    - ENGINEERING MECHANICS AND MATERIALS (385 journals)
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ENGINEERING (1204 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 6)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 233)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 7)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 37)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 30)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 15)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 4)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 8)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 3)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 26)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 258)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 181)
Composites Part B : Engineering     Hybrid Journal   (Followers: 237)
Composites Science and Technology     Hybrid Journal   (Followers: 216)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 14)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 28)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 30)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 42)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Science     Open Access   (Followers: 58)

        1 2 3 4 5 6 7 | Last

Journal Cover Applied Clay Science
  [SJR: 0.826]   [H-I: 83]   [5 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0169-1317
   Published by Elsevier Homepage  [3044 journals]
  • Effects of calcination temperature and the addition of ZnO on coal waste
           activation: A mineralogical and morphological evolution
    • Authors: Raquel Vigil de la Villa; Rosario García; Sagrario Martínez-Ramírez; Moisés Frías
      Pages: 1 - 9
      Abstract: Publication date: 15 December 2017
      Source:Applied Clay Science, Volume 150
      Author(s): Raquel Vigil de la Villa, Rosario García, Sagrario Martínez-Ramírez, Moisés Frías
      Eco-efficient cements based on industrial wastes constitute a priority line of research for the sustainability of the cement sector, in response to the challenges of the circular economy at a European level. Eco-innovation and investigation of new alternative sources of primary materials from waste arise as potential actions directed at the achievement of greater efficiency in the use of resources. From among the broad range of industrial wastes, those that contain kaolinite (K) and phyllosilicates are ideal as active additions in the manufacture of cements, having previously undergone a process of thermal activation. Earlier works have indicated that the chemical reactivity of natural K (untreated kaolin) may be increased through the addition of ZnO as a chemical agent. In this study, the effect of ZnO as a chemical agent is for the first time studied, when added to coal waste in proportions of 0.5, 1.0, 1.5 and 3.0% by weight, prior to the thermal activation process of the waste that is calcinated at 550°, 600°, and 650°C for 2h. The mineralogy and the pozzolanic activity of the activated products are considered, and their influence on the evolution of the hydrated phases at 1, 7, and 28days of reaction in the pozzolan/lime system. Subsequently, the results are compared with those obtained from pure natural kaolinite activated at 600°C/2h, with ZnO addition and without chemical agent ZnO, with an added quantity of 1.0% in weight. The results showed important variations when the chemical activator (ZnO) was used for the natural kaolinite (NK) and the industrial waste. The chemical activator favors the disaggregation of the phyllosilicates from the aggregates, strengthening the pozzolanic reaction in the natural/lime kaolinite system. However, the activator in the coal waste/lime system, in addition to favoring the disaggregation of the aggregate, leaves epitaxial deposits on the surface and on the edges of the materials, saturating the substrate surface loading, with an inhibitory effect on the pozzolanic reaction. The abundance of metakaolinite (MK) and the partial dehydroxylation of the mica with its subsequent reorganization, explains the appearance of these minerals as one of the products of the reaction. With SEM/EDX, the existence of CSH gels of a spongy appearance may be observed following thermal activation of the coal waste; while if the activation is done under the combined effect of temperature and the addition of 1.0% ZnO, then the chemical activator favors the formation of long fibers and the appearance of gels, with compositions similar to LDH and calcium aluminates.

      PubDate: 2017-09-08T03:01:58Z
      DOI: 10.1016/j.clay.2017.08.031
      Issue No: Vol. 150 (2017)
       
  • The Maastrichtian-Danian Dakhla Formation, Eastern Desert, Egypt:
           Utilization in manufacturing lightweight aggregates
    • Authors: Tarek I. Anan; Ahmed G. Abd El-Wahed
      Pages: 10 - 15
      Abstract: Publication date: 15 December 2017
      Source:Applied Clay Science, Volume 150
      Author(s): Tarek I. Anan, Ahmed G. Abd El-Wahed
      The Dakhla Formation at Um El Hueitat area, south of Safaga City, Eastern Desert, Egypt is composed mainly of shale with some marl, limestone and phosphate intercalations. Suitability of the technological sample representing smectitic-rich clay deposits of the Dakhla Formation for lightweight product was studied. The mineralogical and chemical compositions of the technological sample indicate that it is suitable for manufacturing lightweight bloated clay aggregate. This was done by processing its plastic pellets through firing to 1000–1300°C.

      PubDate: 2017-09-14T03:06:36Z
      DOI: 10.1016/j.clay.2017.08.027
      Issue No: Vol. 150 (2017)
       
  • Preparation and characterization of sodium lauroyl sarcosinate adsorbed on
           cetylpyridinium-montmorillonite as a possible antibacterial agent
    • Authors: Saadet Yapar; Mustafa Ateş; Günseli Özdemir
      Pages: 16 - 22
      Abstract: Publication date: 15 December 2017
      Source:Applied Clay Science, Volume 150
      Author(s): Saadet Yapar, Mustafa Ateş, Günseli Özdemir
      An organo-montmorillonite was synthesized to generate a two-level antibacterial agent. The material (Mt-CP-SR) was prepared through the adsorption of sodium lauroyl sarcosinate (SR) on montmorillonite modified with cetylpyridinium (Mt-CP) and its structure was characterized by conducting ATR-FTIR, XRD, and SEM analyses. The results of the ATR-FTIR analyses indicated that SR on the surface could be detected when its amount exceeded the CEC of the Mt. The XRD analyses revealed that the adsorption of CP and SR causes the separation of Mt layers into smaller stacks. The adsorption and desorption study of SR onto and from 0.7 CEC Mt-CP were investigated to determine the amount of SR adsorbed at varying initial SR concentrations and the amount of SR released when diluted with water. Around 140mg of SR could be loaded on one gram of the Mt intercalated with 170mg of CP. The results indicated that desorption of SR from the surface is gradual and SR and CP have strong interactions on the montmorillonite (Mt) surface. The antibacterial activity of the material was tested against E. coli, S. aureus, and P. aeruginosa. Additionally, the SR solutions and CP+SR solutions in equimolar ratios were subjected to antibacterial tests for comparison purposes. SR proved to be effective against all three bacteria and the MIC values were found as 75mg/mL for E. coli, 37.5mg/mL for S. aureus, and 300mg/mL for P. aeruginosa. The MBC was 300mg/mL for E. coli and S. aureus. The solutions of CP+SR mixtures were ineffective against P. aeruginosa, whereas, they were effective against S. aureus. The prepared Mt-CP-SR samples were found to be effective against S. aureus and E. coli. These results indicate that the material could be used in antibacterial liquid soaps, in toothpaste formulations, personal care products, and topical applications against acne, and wounds without any negative contribution to the physico-chemical and detergency properties of the materials.

      PubDate: 2017-09-14T03:06:36Z
      DOI: 10.1016/j.clay.2017.08.025
      Issue No: Vol. 150 (2017)
       
  • Evaluation of organic modification of montmorillonite with ionic and
           nonionic surfactants
    • Authors: Jefferson Lopes Alves; Paulo de Tarso Vieira e Rosa; Ana Rita Morales
      Pages: 23 - 33
      Abstract: Publication date: 15 December 2017
      Source:Applied Clay Science, Volume 150
      Author(s): Jefferson Lopes Alves, Paulo de Tarso Vieira e Rosa, Ana Rita Morales
      This work aims at evaluating the organophilization of montmorillonite with two different types of surfactants: one ionic, containing C16-C18 di(alkyl ester) dimethyl ammonium chloride (EA) and one nonionic, containing ethoxylated tallow amine (ETA). Aqueous dispersion and semi-solid routes were compared in terms of functionalization efficiency by statistical analysis, and supercritical CO2 was performed as a complementary and comparative method. Besides, the effect of the washing process after functionalization was evaluated. X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) and contact angle were used to evaluate the intercalation of surfactants into montmorillonite and process yield. The d001-value was improved by both surfactants intercalation, and the conformations of the species inside the clay minerals were suggested. The final arrangement of the organic species into Mt was modified as a function of the concentration of surfactant added, and by the washing steps. Most process parameters evaluated showed significant effects on d001-value and process yield. The semi-solid method was confirmed as a good alternative route due to its efficiency and it could be an environmentally friendly option to be used. ETA-modified montmorillonites showed similar d001-values (around 4.0nm) and higher thermal stability than EA-modified montmorillonite.

      PubDate: 2017-09-14T03:06:36Z
      DOI: 10.1016/j.clay.2017.09.001
      Issue No: Vol. 150 (2017)
       
  • Synthesis and characterization of 12-tungstophosphoric acid intercalated
           layered double hydroxides and their application as esterification
           catalysts for deacidification of crude oil
    • Authors: Yan Wu; Xinyue Liu; Yanqing Lei; Yue Qiu; Menglu Wang; Hao Wang
      Pages: 34 - 41
      Abstract: Publication date: 15 December 2017
      Source:Applied Clay Science, Volume 150
      Author(s): Yan Wu, Xinyue Liu, Yanqing Lei, Yue Qiu, Menglu Wang, Hao Wang
      12-tungstophosphoric acid (H3PW12O40, HPW) intercalated layered double hydroxides (LDH) (M2+/Al3+ =2, M2+ =Mg2+, Zn2+, Ni2+) were prepared by an ion-exchange method. The as-prepared LDH show a strong reflection around 8.4° corresponding to a basal spacing of 1.05nm, which is considered as heteropolyacid salts or polytungstate intercalated LDH in almost all literature. Further systemic experiments and characterizations demonstrated that such reflection can be attributed to the intercalation of HPW, in which HPW may graft with the vacancies in the layer and orient in the interlayer with the C2 axis perpendicular to the layers. HPW intercalated LDH show higher catalytic activity than nitrate LDH for the esterification between ethylene glycol and naphthenic acids in crude oil. It is found that the total amount of acidic sites dominates the esterification activity. Due to the immobilized HPW active sites and the enlarged interlayer space, HPW intercalated LDH may act as an interlayer catalytic reactor to improve the esterification activity.
      Graphical abstract image

      PubDate: 2017-09-14T03:06:36Z
      DOI: 10.1016/j.clay.2017.09.007
      Issue No: Vol. 150 (2017)
       
  • A two-step technique for tensile strength of montmorillonite/polymer
           nanocomposites assuming filler morphology and interphase properties
    • Authors: Yasser Zare; Kyong Yop Rhee
      Pages: 42 - 46
      Abstract: Publication date: 15 December 2017
      Source:Applied Clay Science, Volume 150
      Author(s): Yasser Zare, Kyong Yop Rhee
      This paper presents a two-step methodology for prediction of tensile strength in montmorillonite/polymer nanocomposites (MPN) assuming the effects of montmorillonite morphology (intercalation/exfoliation) and interphase properties. The suggested technique is evaluated by the experimental data of tensile strength in some samples. A good agreement is shown between experimental measurements and predictions, which can determine the intercalation/exfoliation level and interphase properties. A high aspect ratio of Mt platelets increases the interfacial interaction and mechanical involvement between polymer chains and nanoparticles causing high strengthening effect. Moreover, high concentration of well-exfoliated Mt as well as thick and strong interphase produces desirable tensile strength in MPN.

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.026
      Issue No: Vol. 150 (2017)
       
  • Sustainable catalytic properties of silver nanoparticles supported
           montmorillonite for highly efficient recyclable reduction of methylene
           blue
    • Authors: Ning Wang; Yunxia Hu; Zongren Zhang
      Pages: 47 - 55
      Abstract: Publication date: 15 December 2017
      Source:Applied Clay Science, Volume 150
      Author(s): Ning Wang, Yunxia Hu, Zongren Zhang
      Water contamination by organic dyes has become a serious environmental pollution. Here, a facile, green and cost-effective synthesis approach was developed to in situ grow silver nanoparticles (Ag NPs) on the eco-friendly and low cost natural material montmorillonite (Mt) through dopamine chemistry. The loading amount of silver on the montmorillonite reached 20 mass %. The Ag NPs supported montmorillonite (Ag NPs@Mt) exhibited excellent catalytic performances to reduce a model organic dye methylene blue in the presence of NaBH4 with catalytic efficiency higher than 98% and apparent reduction rate constant k app higher than 1.70min−1. More importantly, the Ag NPs@Mt was proven to show excellent recyclability for at least 20cycles and long-term stability for one month soaking in water. This low-cost and recyclable Ag NPs@Mt shows great potential in large scale application to treat dye containing wastewater.
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.024
      Issue No: Vol. 150 (2017)
       
  • Mechanochemical activation of serpentine for recovering Cu (II) from
           wastewater
    • Authors: Pengwu Huang; Zhao Li; Min Chen; Huimin Hu; Zhiwu Lei; Qiwu Zhang; Wenyi Yuan
      Pages: 1 - 7
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Pengwu Huang, Zhao Li, Min Chen, Huimin Hu, Zhiwu Lei, Qiwu Zhang, Wenyi Yuan
      In this paper, a novel method for copper removal was introduced, in which serpentine, a hydrated magnesium silicate, was activated by mechanical force to raise its reactivity as high as Mg hydroxide to remove Cu (II) from wastewater. Copper precipitation occurred easily when agitating the activated serpentine in copper sulfate solution. Characterizations of the activated samples and the samples after treatment of Cu (II) were also performed by X-ray diffraction (XRD), Thermogravimetry & Differential Scanning Calorimetry (TG-DSC). Chemical precipitation with wroewolfeite (CuSO4·3Cu(OH)2·2H2O), a basic copper sulfate, rather than the well known general adsorption by the raw mineral without activation, was formed and gave a very high capacity up to 538.8mg/g for copper removal, comparable with the precipitation by alkaline neutralization of Mg/Ca hydroxide. One more important advantage of using the activated serpentine allowed a selective copper removal from the solution with other metals as Ni (II), Mn (II), Zn (II) and Cd (II) remaining in the solution. The copper precipitate without coexistence of other metals may serve as a good source for copper recycling. The process based on using activated serpentine exhibits the merits for both environmental purification and copper recovery from secondary source/waste, providing a usable method for waste serpentine source as well.
      Graphical abstract image

      PubDate: 2017-09-08T03:01:58Z
      DOI: 10.1016/j.clay.2017.08.030
      Issue No: Vol. 149 (2017)
       
  • Comparison of dehydration in kaolin and illite using DC conductivity
           measurements
    • Authors: Marian Kubliha; Viera Trnovcová; Ján Ondruška; Igor Štubňa; Ondrej Bošák; Tiit Kaljuvee
      Pages: 8 - 12
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Marian Kubliha, Viera Trnovcová, Ján Ondruška, Igor Štubňa, Ondrej Bošák, Tiit Kaljuvee
      Temperature dependencies of the DC conductivity of kaolin and illite are measured from 20°C up to 450°C using “as received” samples and samples after heating to 400°C and 450°C. Release of physically bound water (PBW) from green kaolin shows two maxima, at 55°C and 298°C. Release of the PBW from green illite takes place in 3 steps at 72°C, 186°C, and 298°C. Up to 200°C, the dominant charge carriers are H+ and OH– ions in both materials. At higher temperatures, alkali ions (both Na+ and K+ in kaolin, prevalently K+ in illite) are the dominant charge carriers with the conduction activation energy of 1.19±0.02eV in kaolin and of 1.12±0.02eV in illite. Above 400°C, dehydroxylation runs in illite. Due to this process, the DC conductivity of illite increases; in partly dehydroxylated illite, higher conduction activation energy (1.22eV) indicates that alkali metal ions are moving in a more disordered structure. In kaolin, dehydroxylation starts only above 450°C.

      PubDate: 2017-09-08T03:01:58Z
      DOI: 10.1016/j.clay.2017.08.012
      Issue No: Vol. 149 (2017)
       
  • Accelerated sorption of boron from aqueous solution by few-layer
           hydrotalcite nanosheets
    • Authors: Zhu Shu; Qinghai Guo; Yun Chen; Jun Zhou; Wei Guo; Yaowu Cao
      Pages: 13 - 19
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Zhu Shu, Qinghai Guo, Yun Chen, Jun Zhou, Wei Guo, Yaowu Cao
      Boron is toxic to humans and animals at high concentrations. Hydrotalcite (HT) is an anion clay mineral capable of removing boron from water. In this work, the strategy of delamination of hydrotalcite was proposed and demonstrated to be effective in accelerating the boron sorption. Few-layer hydrotalcite (FHT) nanosheets were facilely obtained via rinsing the co-precipitated HT with acetone before final isolation, and achieved boron sorption equilibrium about 10 times faster than HT. The 2D nanosheet morphology helped FHT not only to disperse more fully in boron solution but also to expose more active sites on its external surface. As a result, the route for boron transferring from bulk solution to active sorption sites was effectively shortened on FHT, which finally induced a rapid boron removal.

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.09.003
      Issue No: Vol. 149 (2017)
       
  • Evaluation of polymeric Al-modified bentonite for its potential
           application as ceramic coating
    • Authors: J.M. Martinez; C. Volzone; L.B. Garrido
      Pages: 20 - 27
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): J.M. Martinez, C. Volzone, L.B. Garrido
      A polymeric Al-modified bentonite (B-OHAl) obtained by intercalation of OH-Al species was used as precursor for mullite-containing coatings. Raw clay and B-OHAl were characterized by X-ray fluorescence (XRF), Infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA). Rheological and electrokinetic behavior of B-OHAl dispersions were optimized by the addition of sodium polyacrylate (NaPA) for its use in dip coating on ceramic substrates. Moderate densification and mullite development of B-OHAl by thermal treatment up to 1200°C was observed by mercury intrusion porosimetry (MIP), XRD and scanning electron microscopy SEM. NaPA addition on dispersions and an increase in porosity values in substrate led to higher amounts of coating retained in dip coated composites sintered at 1200°C.

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.09.004
      Issue No: Vol. 149 (2017)
       
  • Biosafe organic diacid intercalated LDH/PVC nanocomposites versus pure LDH
           and organic diacid intercalated LDH: Synthesis, characterization and
           removal behaviour of Cd2+ from aqueous test solution
    • Authors: Shadpour Mallakpour; Masoud Hatami
      Pages: 28 - 40
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Shadpour Mallakpour, Masoud Hatami
      Highly real nanostructured clay adsorbents of layered double hydroxide (LDH) intercalated with biosafe and anionic organic diacid was produced at a constant pH with the coprecipitation method. XRD results disclosed that organic anionic segment is horizontally oriented in the interlayer space, which is obvious from developed basal spacing of 0.76 to 1.36nm. Also, a successfully LDH intercalation with examined biosafe diacid was observed using FT-IR and TGA analysis. Organo-intercalated LDH (I-LDH)/PVC nanocomposites (NCs) with different content of I-LDH loading were organized through ultrasound irradiation as a green method. The morphological behaviors and structured properties of achieved NCs were studied by characteristic analyses such as FT-IR, XRD FE-SEM and TEM. Results of thermal analysis disclosed positive influence of I-LDH on degradation temperature in compared to the neat PVC, and also residue at 800°C enhanced from 23 to 42%. The resulting LDH samples were studied for their performance in removing Cd2+ metal ion from aqueous test solution and the removal efficiency of these materials at proper pH, different adsorbent mass, Cd2+ concentrations and different times were documented by atomic adsorption spectrometry. In all samples, with the developed in the adsorbent mass, the removal efficiency for Cd2+ was improved at the 50mg/L of metal ion concentration and constant pH of 7.0. The maximum Cd2+ uptake was 86.17% related to the I-LDH/PVC NC 15wt%, and also the experimental data indicated a good compliance with the Langmuir isotherm and pseudo-second-order kinetic model for different LDH samples.
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.09.006
      Issue No: Vol. 149 (2017)
       
  • Chamotte clay as potential low cost adsorbent to be used in the palm
           kernel biodiesel purification
    • Authors: Flavia D. Santos; Leyvison Rafael V. da Conceição; Annie Ceron; Heizir F. de Castro
      Pages: 41 - 50
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Flavia D. Santos, Leyvison Rafael V. da Conceição, Annie Ceron, Heizir F. de Castro
      Solid waste from the red ceramic industry (chamotte clay) was assessed as glycerol adsorbent for biodiesel purification by dry washing. Its structure and composition was analyzed by several techniques, such as X-ray diffraction, FT-IR, scanning electron microscopy and particle size. By using a simulated medium (5w/v% glycerol in an ethanol solution), a face centered composite design was used to analyze the combined effect of chamotte concentration and temperature on glycerol removal. Chamotte levels of 2.5w/v% at 45°C maximized glycerol removal (1282mgglycerolg−1) with minimum loss of adsorbate. Kinetic data on glycerol adsorption by chamotte clay could be adjusted using the pseudo-second order model, which indicates that the rate-limiting step may be chemisorption. Moreover, chamotte clay was used for purifying ethyl biodiesel samples from palm kernel oil by chemical and biochemical catalysis. In the presence of chamotte clay, low glycerol levels (<0.02wt%) were found in comparison with crude biodiesel (0.29±0.03wt%). Chamotte clay was also able to remove residual levels of monoacylglycerols and diacylglycerols and provided samples with properties that are similar to those attained by traditional wet washing.
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.09.009
      Issue No: Vol. 149 (2017)
       
  • Predicting the swelling pressure of MX-80 bentonite
    • Authors: Vicente Navarro; Gema De la Morena; Ángel Yustres; Jesús González-Arteaga; Laura Asensio
      Pages: 51 - 58
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Vicente Navarro, Gema De la Morena, Ángel Yustres, Jesús González-Arteaga, Laura Asensio
      This paper proposes a calculation procedure to estimate the swelling pressure of bentonites. The experimental information needed to obtain the estimations can be obtained from relatively conventional tests, including the determination of the water retention curve, and swelling pressure tests using oedometric sample holders. This allows to obtain physically based predictions of the changes in swelling pressure with environment salinity. To facilitate the calculations, an open access spreadsheet in which the proposed approach has been implemented is attached as Supplementary material. A set of significant swelling pressure tests are modelled, obtaining very good fits. The fits not only build confidence in the proposed methodology, but also improve the validation of the hydro-chemo-mechanical formulation on which the proposed procedure is based.

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.014
      Issue No: Vol. 149 (2017)
       
  • Functional characterization on colloidal suspensions containing xanthan
           gum (XGD) and polyanionic cellulose (PAC) used in drilling fluids for a
           shale formation
    • Authors: Yurany Villada; Felipe Gallardo; Eleonora Erdmann; Natalia Casis; Laura Olivares; Diana Estenoz
      Pages: 59 - 66
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Yurany Villada, Felipe Gallardo, Eleonora Erdmann, Natalia Casis, Laura Olivares, Diana Estenoz
      Drilling fluids are employed in the operation of hydrocarbon exploitation. Two kinds of drilling fluids are commonly used: water based muds and oil based muds. The oil based muds are characterized by their high performance in unconventional reservoirs due to the very low interaction with the reactive formation. Their environmental impact promotes the design of water based muds that present low toxicity. In this paper a water based mud for shale formation with similar rheological characteristics to the oil based mud used in the oil industry of Argentina was designed and the effect of xanthan gum and polyanionic cellulose on the main functional characteristics was studied. Rheometric analysis showed a shear-thinning behavior with notable effect on the concentration of polymers. After dynamic aging test, fluids with composition of PAC=8.00g/L and XGD=3.00g/L exhibited rheological properties very close to oil base mud. Structural changes were assessed from optical microscopy and scanning electron microscopy. Particles agglomeration due to the presence of polymers was observed. Furthermore, mud filtration essays allowed to evaluate the performance of PAC as control agent. The Carreau model and statistical analysis were used to determine rheological parameters.
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.020
      Issue No: Vol. 149 (2017)
       
  • Impact of an integrated no-till soybean–beef cattle production system on
           Oxisol mineralogy in southern Brazil
    • Authors: Vanessa Thoma Bertolazi; Alberto Vasconcellos Inda; Laurent Caner; Amanda Posselt Martins; Marcos André B. Vaz; Marine Bonnet; Ibanor Anghinoni; Paulo César F. Carvalho
      Pages: 67 - 74
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Vanessa Thoma Bertolazi, Alberto Vasconcellos Inda, Laurent Caner, Amanda Posselt Martins, Marcos André B. Vaz, Marine Bonnet, Ibanor Anghinoni, Paulo César F. Carvalho
      Agricultural activities in the state of Rio Grande do Sul (RS), southern Brazil, have traditionally been quite intensive and led to decreased overall soil quality, and to depletion of soil organic matter and nutrients. There have been attempts at restoring soil quality by using integrated crop–livestock systems (ICLS). ICLS in association with no-tillage (NT) potentially increase soil organic matter content and nutrient supplies. The aim of this work was to assess the influence of grazing intensity in three different treatments [viz., intensive grazing (IG), moderate grazing (MG) and no grazing (NG)] on the mineralogy of an Oxisol in an integrated soybean–cattle beef production system in southern Brazil by using various types of methods and tests. Mineralogical XRD analyses of the clay fraction (<2μm) showed it to consist mainly of kaolinite and 2:1 clay minerals of the hydroxy-interlayered mineral (HIM) type. The reflections for 2:1 clay minerals under the IG treatment were better defined than those for the minerals under NG, which suggests the prevalence of HIMs. The 2:1 clay minerals in the IG group exhibited expandable layers. Splitting the clay fraction into three subfractions according to size (<0.05μm, 0.05–0.1μm and 0.1–2μm) exposed considerable alterations. Thus, hydroxy-aluminum interlayered vermiculite (HIV-Al) was present irrespective of treatment. Also, the HIV-Al reflection was better defined under IG and MG than under NG, which suggests strong aluminization of 2:1 clay minerals. Chemical analyses revealed a decrease in total organic carbon (TOC) with increasing depth in all treatments. The decrease was especially marked under NG by effect of the absence of animals favoring accumulation of plant shoots. pHwater was higher under IG as a result of the removal of aluminum from the soil solution increased aluminization of 2:1 clay minerals. K concentrations in solution were low under IG as a result of the formation of HIMs and/or swelling layers with exchangeable K; by contrast, solution K levels under NG where high owing to the absence of HIMs. The presence of animals, which increases K availability through animal wastes, may have resulted in competition between exchangeable K+ and Al3+ to form HIMs. Without splitting the clay fraction it would have been impossible to confirm the mineralogical alteration in 2:1 phyllosilicates due to the impact of ICLS systems.

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.028
      Issue No: Vol. 149 (2017)
       
  • Analytical solution for clay plug swelling experiments
    • Authors: Simon A. Mathias; H. Chris Greenwell; Charlotte Withers; Ali R. Erdogan; Jim N. McElwaine; Chris MacMinn
      Pages: 75 - 78
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Simon A. Mathias, H. Chris Greenwell, Charlotte Withers, Ali R. Erdogan, Jim N. McElwaine, Chris MacMinn
      Clay swelling experiments frequently involve monitoring the one-dimensional displacement with time of an initially dry clay plug as it imbibes water from a supply at its base. This article presents a new analytical solution for interpreting such experiments based on Richards' equation for flow in a partially saturated porous medium combined with a linear empirical function relating moisture ratio with void ratio. The analytical solution is described by just two parameter groups. The first parameter group describes the swelling potential of the clay. The second parameter group describes the rate at which the swelling plug reaches equilibrium, which is controlled by permeability and capillary pressure. Application of the analytical solution is demonstrated by calibration to one-dimensional displacement data from clay swelling experiments for an illite and bentonite clay.

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.07.021
      Issue No: Vol. 149 (2017)
       
  • Development of cost effective bentonite adsorbent coating for the removal
           of organic pollutant
    • Authors: Shazlina Abd Hamid; Mohammad Shahadat; Suzylawati Ismail
      Pages: 79 - 86
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Shazlina Abd Hamid, Mohammad Shahadat, Suzylawati Ismail
      The present study deals with the development of an innovative cost effective bentonite adsorbent coating (BAC) and simple mathematical equations are applied to enumerate coating requirement in treating textile effluent. The BAC has been successfully used for the removal of cationic dye from industrial wastewater. It has very good potential to be commercialized and applied by industries innovatively on the existing facilities with simple modifications. By installing bentonite coated fins inside tank, the concentration of dye can be easily reduced up to 90%. The BAC demonstrates good temperature and water resistant efficiency which can be easily coated on many surfaces. The best thickness and surface area of BAC for the optimal adsorption of dye (277.8mgg−1) was found as 87μm and 1.12×10−2 m2, respectively. The equilibrium adsorption data were best fitted by the Langmuir isotherm which indicates homogeneous monolayer adsorption. The mathematical formula obtained from isotherm model could be used in the removal and recovery of cationic dye (organic pollutant) in textile industry on large scale.
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.07.022
      Issue No: Vol. 149 (2017)
       
  • Naturally occurring layered-mineral magnesium as a bactericidal against
           Escherichia coli
    • Authors: Luis Zarate-Reyes; Cynthia Lopez-Pacheco; Antonio Nieto-Camacho; María Teresa Ramírez Apán; Eduardo Palacios; Stephan Kaufhold; Kristian Ufer; Eduardo Garcia-Zepeda; Javiera Cervini-Silva
      Pages: 87 - 96
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Luis Zarate-Reyes, Cynthia Lopez-Pacheco, Antonio Nieto-Camacho, María Teresa Ramírez Apán, Eduardo Palacios, Stephan Kaufhold, Kristian Ufer, Eduardo Garcia-Zepeda, Javiera Cervini-Silva
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.07.035
      Issue No: Vol. 149 (2017)
       
  • Effect of waste rubber fibres on the geotechnical properties of clay
           stabilized with cement
    • Authors: J.S. Yadav; S.K. Tiwari
      Pages: 97 - 110
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): J.S. Yadav, S.K. Tiwari
      The voluminous generation of discarded waste rubber tires of about 1.5 million per year has created an aggravating situation across the globe because it exerts the deleterious effect on the human health and ecological systems. This paper focuses on the influence of inclusion of waste rubber tire fibres on some of the geotechnical properties of uncemented/cemented clay. For this investigation, three percentages of cement (0%, 3%, and 6%) and five percentages of rubber fibre (0%, 2.5%, 5%, 7.5%, and 10%) were considered. The tests namely, compaction, unconfined compressive strength, split tensile strength, California bearing ratio, swelling pressure, wet/dry cycles durability along with the scanning electron microscopy were conducted on the clay-cement-rubber fibre mixtures to ascertain the suitability of rubber fibres with cement stabilized clay. The test results revealed that the incorporation of rubber fibre reduces the unconfined compressive strength and split tensile strength of cement-stabilized clay but prosperously improves the rate of loss of post-peak strength and change the brittle failure behavior of cemented clay to ductile. The results of California bearing ratio test showed that the resistance against the penetration of the cement stabilized clay decreases as the content of rubber fibre increases. The swelling pressure of the clay was found to decrease with the increase in cement and rubber fibre content. The encouraging results of wet/dry cycles durability test proves the propriety of other tests on clay-cement-rubber fibre mixtures. Based on the test results, the maximum percentage of rubber fibre content mixed with cement-stabilized clay was found to be 7.5%. The study has shown that clay-cement-rubber fibre mixtures containing 6% cement and upto to 7.5% rubber fibre can be use as fill material, backfill material for retaining wall, sub-base of low volume traffic roads, and side slope of the canal.

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.07.037
      Issue No: Vol. 149 (2017)
       
  • Gastroprotective effects of Tunisian green clay on ethanol-induced gastric
           mucosal lesion in rats
    • Authors: Ridha Ben Ali; Anouar Ounis; Dorra Ben Said; Chadli Dziri; Michèle Véronique El May
      Pages: 111 - 117
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Ridha Ben Ali, Anouar Ounis, Dorra Ben Said, Chadli Dziri, Michèle Véronique El May
      Natural green clay is mostly used in pharmaceutical and cosmetic products. The effect of this raw material from different outcrops around the world demonstrates its beneficial role on human health. The green clay from southern Tunisia is widely used in local traditional medicine and cosmetic preparations but its biological activity in vivo has not been studied yet. For this reason, this work was interested in deciphering the properties of the Tunisian green clay such as mineralogy composition and biological effect. In fact, the mineralogical study of this green clay shows two types of clay minerals such as illite and kaolinite with proportion of 75% and 25%, respectively. In order to study the biological effect, green clay was administered orally to rats for 1h at 50, 75, 100 and 125mg/kg doses. After that, ethanol 95% was given to these rats to induce a gastric ulcer. Then, several parameters (e.g. Ulcer index, protective rate, mucus production gastric and mucosa histology) were measured to evaluate the gastroprotective activity. The histology study shows normal gastric mucosa in rats pretreated at 75, 100 and 125mg/kg doses and the decrease of Ulcer Index (%I=97%) and lesions areas. The oral administing mixture of Tunisian green clay with ethanol in rats induces severe mucosal lesion and hemorrhagic bands. This clay colored by methylene blue shows that clay was linked to the mucus excreted by the stomach surface. The green clay didn't neutralize ethanol gastro toxicity and formed a layer on the gastric mucosa to protect it by a mechanical action. When investigated on rats at an effective dose treatment (75mg/kg) for 30days, the subchronic toxicity test of green clay did not reveal any signs of mortality and toxicity, and it demonstrated the normal hematological and biochemical parameters of rats. Thus, the Tunisian green clay can be considered as a safe natural product since it has a potential gastroprotective activity on ethanol induced gastric mucosal lesions in rats.

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.008
      Issue No: Vol. 149 (2017)
       
  • Synthesis, characterization and photocatalytic activity of TiO2-halloysite
           and Fe2O3-halloysite nanocomposites for photodegradation of chloroanilines
           in water
    • Authors: Beata Szczepanik; Paweł Rogala; Piotr M. Słomkiewicz; Dariusz Banaś; Aldona Kubala-Kukuś; Ilona Stabrawa
      Pages: 118 - 126
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Beata Szczepanik, Paweł Rogala, Piotr M. Słomkiewicz, Dariusz Banaś, Aldona Kubala-Kukuś, Ilona Stabrawa
      The TiO2- and Fe2O3-halloysite nanocomposites were prepared using acid treated halloysite from Poland. The TiO2-halloysite nanocomposite was synthesized using titanium isopropoxide as a precursor under hydrothermal treatment at 65°C. The Fe2O3-halloysite nanocomposite was obtained using the sol-gel method. Gelatinous ferric hydroxide was applied as a ferric precursor. Chemical and phase composition, particle morphology, and physical properties of these nanocomposites were studied with the use of wavelength dispersive X-ray fluorescence (WDXRF), X-ray diffraction (XPRD), electron microscopy (TEM), FTIR technique, and N2 adsorption/desorption isotherms. The photocatalytic activities of TiO2- and Fe2O3-halloysite nanocomposites for aniline, 2-chloro-, and 2,6-dichloroaniline degradation under the UV irradiation were determined. The TiO2- and Fe2O3-halloysite nanocomposites showed significantly higher photocatalytic activity in decomposing aniline and its chloro derivatives than that of the commercial TiO2, commercial photocatalyst P25, and halloysite contains natural TiO2 dispersed on their surface.
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.016
      Issue No: Vol. 149 (2017)
       
  • Removal of dyes by a new nano–TiO2 ultrafiltration membrane deposited on
           low-cost support prepared from natural Moroccan bentonite
    • Authors: Abdelmjid Bouazizi; Majda Breida; Brahim Achiou; Mohamed Ouammou; José Ignacio Calvo; Abdelah Aaddane; Saad Alami Younssi
      Pages: 127 - 135
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Abdelmjid Bouazizi, Majda Breida, Brahim Achiou, Mohamed Ouammou, José Ignacio Calvo, Abdelah Aaddane, Saad Alami Younssi
      This paper reports the preparation and characterization of a low-cost nano-TiO2 ultrafiltration membrane deposited on a bentonite support. The ultrafiltration layer was obtained by dip-coating process using nano-TiO2, followed by sintering at 750°C. Environmental Scanning Electron Microscope (ESEM) analysis of prepared ultrafiltration membrane showed that the deposited layer is homogeneous and shows a good adhesion on the support presenting a mean thickness of 4±0.2μm. The average pore diameter and water permeability of the obtained membrane are respectively 10±0.5nm and 16.08L/hm2 bar. The membrane performance was evaluated by filtration of three different dyes: two anionic (Direct red 80 and Acid orange 74) and a cationic one (Methylene blue). Effect of feed pH and dyes concentration on membrane rejection was investigated at a pressure of 4bar. The experimental filtration results showed that rejection of Direct Red 80, Acid Orange 74 and Methylene Blue achieved maximum values of 98%, 85% and 94% respectively, depending on filtration conditions and each dye characteristics.
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.019
      Issue No: Vol. 149 (2017)
       
  • Montmorillonite/poly(urethane-siloxane) nanocomposites: Morphological,
           thermal, mechanical and surface properties
    • Authors: Ivan S. Stefanović; Milena Špírková; Sanja Ostojić; Plamen Stefanov; Vladimir B. Pavlović; Marija V. Pergal
      Pages: 136 - 146
      Abstract: Publication date: 1 December 2017
      Source:Applied Clay Science, Volume 149
      Author(s): Ivan S. Stefanović, Milena Špírková, Sanja Ostojić, Plamen Stefanov, Vladimir B. Pavlović, Marija V. Pergal
      The aim of this work was to prepare and characterize the series of segmented polyurethane nanocomposites (PUNC) modified with poly(dimethylsiloxane) and based on montmorillonite (Mt) as a nano-filler. α,ω-Dihydroxy-poly(propylene oxide)-b-poly(dimethylsiloxane)-b-poly(propylene oxide) macrodiol was used as the soft segment component, while 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD) were selected as the hard segment components. PUNC were synthesized with different ratio of hard/soft segments. PUNC were morphologically, structurally, thermally, mechanically and surface characterized by XRD, TEM, FTIR, AFM, TGA, DMTA, tensile test, XPS, contact angle, surface free energy (SFE) and water absorption measurements. Added Mt (1wt%) was completely delaminated and well dispersed in the form of mixed exfoliated/intercalated layers in the polymer matrix, and that PUNC have more pronounced microphase separated morphology, higher thermal stability, superior mechanical features, enhanced surface properties, as well as outstanding hydrophobicity. Due to the improved features, developed polymers can be considered as candidates for materials with specific biomedical applications or as waterproof coatings.
      Graphical abstract image

      PubDate: 2017-09-20T03:10:43Z
      DOI: 10.1016/j.clay.2017.08.021
      Issue No: Vol. 149 (2017)
       
  • Structures of nonionic surfactant modified montmorillonites and their
           enhanced adsorption capacities towards a cationic organic dye
    • Authors: Gaofeng Wang; Shan Wang; Zhiming Sun; Shuilin Zheng; Yunfei Xi
      Pages: 1 - 10
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Gaofeng Wang, Shan Wang, Zhiming Sun, Shuilin Zheng, Yunfei Xi
      This work aims to prepare and characterize novel organo-montmorillonites (OMts) using a nonionic surfactant - octylphenol polyoxyethylene ether (OP-10), and apply the materials for the removal of cationic organic dyes. The nonionic surfactant OP-10 can be successfully intercalated into the interlayer of montmorillonite and the obtained OMts still keep cation exchange capacity. The structural configuration of surfactant molecules between clay mineral layers varies from the surfactant loadings. Moreover, OMts with higher surfactant loadings have higher organic carbon content but lower specific surface area. The prepared OMts showed enhanced adsorption capacities towards cationic organic dye methylene blue (MB), and the adsorption amount increases with an increase of surfactant loading. The high adsorption capacity can be attributed to the fact that the novel OMts still keep cationic exchange capacity and OP-10 has plentiful polyoxyethylene ether chains in its molecule structure, which can capture MB molecules through hydrogen bonding. A probable mechanism for the removal of MB was proposed to be a synergistic effect of ion exchange, partition adsorption, hydrogen bonding and electrostatic interactions. Kinetic and isotherm data could be fitted with pseudo-second order model and Langmuir isotherm. The adsorption thermodynamics study has proved the spontaneous and endothermic nature of the adsorption process. The nonionic surfactant modified OMts could be promising candidate adsorbents for the removal of cationic organic dyes.
      Graphical abstract image

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.001
      Issue No: Vol. 148 (2017)
       
  • Determination of kaolinite floc size and structure using interface
           settling velocity
    • Authors: Tsuguki Kinoshita; Katsuya Nakaishi; Yoshihiro Kuroda
      Pages: 11 - 16
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Tsuguki Kinoshita, Katsuya Nakaishi, Yoshihiro Kuroda
      Although interface settling methods are generally simple, they are not used to determine physical properties such as size of flocs because the relationship between the physical properties of a floc during the settling process and its settling velocity is poorly understood. In this study, the interface settling method was extended to soft matter such as kaolinite floc, and a technique was developed to measure the size and diameter of the floc during the settling process using an interface settling method. An equation proposed by Michaels and Bolger, based on the relationship between interface settling velocity and the solid volume concentration of interfering hard spheres as originally developed by Richardson and Zaki, can be applied to soft matter such as clay floc. The present study demonstrated that the effective volume of floc, as well as the diameters of individual floc particles, can be measured by the interface settling method. This was achieved by incorporating the equation for the settling of spheres in a viscous fluid into Michaels and Bolger's settling velocity equation. To investigate the validity of the effective volume and diameter of floc, the diameter and settling velocity were also measured visually. The experimental work in this study involved constructing a device in which soft floc material could settle without interruption, recording the settling with a video camera attached to an optical microscope, and measuring the diameters of individual flocs and their settling velocities from the recorded images. The interface settling method and the optical visualization method provide similar results for the effective volume and the diameter of the floc particles when they are compared at the same pH and the same ionic concentrations. This work demonstrates that the interface settling method is an efficient way to measure the size and diameter of soft matter such as kaolinite floc.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.07.024
      Issue No: Vol. 148 (2017)
       
  • Removal of cyanobacterial anatoxin-a from water by natural clay adsorbents
    • Authors: Jan Bialczyk; Piotr Natkański; Piotr Kuśtrowski; Urszula Czaja-Prokop; Beata Bober; Ariel Kaminski
      Pages: 17 - 24
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Jan Bialczyk, Piotr Natkański, Piotr Kuśtrowski, Urszula Czaja-Prokop, Beata Bober, Ariel Kaminski
      Adsorption of the cyanobacterial anatoxin-a (ANTX-a) was tested on three different natural clay minerals (palygorskite - Pal, kerolite - Ker and sepiolite - Sep) and one clay (bentonite – Bent) mainly composed from montmorillonite (Mt). The amount of adsorbed/desorbed ANTX-a was measured by HPLC method. To determine the structure, porosity and composition of the tested clay minerals and clay, the samples were characterized by means of XRD, low temperature nitrogen adsorption, Zeta-APS, DRIFT and XRF. Adsorption of ANTX-a on the samples was very rapid in the initial stage of incubation time (up to 5min) and reached equilibrium after 2–15min. The maximal ANTX-a removal ranged from 34.2%, 44.8% and 64.5% for Bent, Sep and Pal, respectively, to 92.1% for Ker. There was an obvious correlation between the adsorption capacity of ANTX-a and the surface area (SBET) of the tested materials. The highest efficiency of ANTX-a adsorption was found for Ker with the highest SBET (247m2/g), while Bent characterized by a low SBET (43m2/g) showed a weaker adsorption capacity for this toxin. A neutral pH appeared to be the best for the elimination of ANTX-a, which is hydrophilic and positively charged under these conditions. An increase in the pH caused the instability of ANTX-a as well as the decrease in the adsorption capacity. The stability of ANTX-a adsorbed on the clay surface was tested using elution with methanol. The highest amount of ANTX-a was recovered by flushing of Pal and Sep (48.6% and 38.6% of the initial value, respectively), whilst the smallest amount for Ker (10.7%) and Bent (3.6%). The complex porosity of Pal and Sep caused the easier evacuation of adsorbed species from the entire surface. On the other hand, accessibility of the pore system for Ker and Bent samples as well as participation of physisorption and chemisorption, resulted in the straitened removal of adsorbed species. The low cost of natural clays, which are simple to obtain and able to adsorb ANTX-a, makes them good candidates for water purification.
      Graphical abstract image

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.07.026
      Issue No: Vol. 148 (2017)
       
  • Occurrence and origin of pore-lining chlorite and its effectiveness on
           preserving porosity in sandstone of the middle Yanchang Formation in the
           southwest Ordos Basin
    • Authors: Shifa Zhu; Xiaoxu Wang; Yi Qin; Ye Jia; Xiaomin Zhu; Jiatang Zhang; Yunqi Hu
      Pages: 25 - 38
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Shifa Zhu, Xiaoxu Wang, Yi Qin, Ye Jia, Xiaomin Zhu, Jiatang Zhang, Yunqi Hu
      The occurrence and origin of pore-lining chlorites in sandstone were studied using mineralogical and crystal chemical analysis and their effectiveness on preserving porosity was discussed. During the sedimentary period of the middle Yanchang Formation, the two provenance and sedimentary systems of the southwest and northeast developed in the southwest Ordos Basin. In the Northeast of the study area, the content of biotite flakes is approximately 10vol%. Pore-lining chlorites prefer to grow on the surfaces of fine-grained detrital quartz and feldspar but not on ductile grains such as biotite. Pore-lining chlorites that developed during the early stage of eodiagenesis (<90°C) probably locally increased the compressive strength of the rock, in places with residual intergranular pores. The chlorites within different sand bodies show slight variations in their chemical composition. After initial mechanical compaction, the formation of authigenic chlorites (brunsvigite and diabantite) was probably related to the hydrolysis and alteration of biotite fragments and the migration of diagenetic fluid. In the Northeast, only 2vol% of the chlorite rims significantly inhibited quartz overgrowth, preserving the primary porosity. However, they probably blocked and delayed the dissolution of acids to feldspar. The porosity probably decreased when the authigenic chlorite content exceeded 9.38vol%. In the Southwest, the authigenic chlorite is rare and quartz-overgrown cement is widespread, causing poor reservoir quality. Authigenic chlorites increase with the content of biotite flakes in the northeast and southwestern parts of the study area, but excess ductile biotite flakes and authigenic chlorites have negative effects on reservoir quality.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.005
      Issue No: Vol. 148 (2017)
       
  • An insight in the structure of a palygorskite from Palygorskaja: Some
           questions on the standard model
    • Authors: Javier García-Rivas; Manuel Sánchez del Río; Emilia García-Romero; Mercedes Suárez
      Pages: 39 - 47
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Javier García-Rivas, Manuel Sánchez del Río, Emilia García-Romero, Mercedes Suárez
      In this study we analyze in detail a palygorskite from Palygorskaja. This palygorskite is situated in the context of the existing studies using X-ray powder diffraction analysis. Moreover, a novel microdiffraction study on a small bunch of fibers shows highly structured 2D diffraction patterns that allow to decipher some information on the microstructure, thus overcoming the uncertainty usually originated by large samples containing mixtures and impurities. Structural data provided by Chisholm (1992) are used to simulate 1D and 2D powder and fiber diffraction patterns for palygorskite, which are compared with the experimental results. We performed simulations for powder and fiber diffraction and we centered our attention in the region of interest with d-spacings between 4.0 and 4.5Å. This palygorskite is consistent with a purely orthorhombic palygorskite, based on good agreement of data with simulations. The experimental results present some reflections not found in the simulations. These reflections are interpreted as corresponding to other hk1 planes of palygorskite. They do not match any reflection from the monoclinic structural model nor from probable impurities, reinforcing the interpretation of them being intrinsic to the structure of the mineral. Our findings suggest a revisal of the commonly accepted structure of palygorskite. They correspond to hk1 planes of palygorskite, and they do not match any reflection neither from the monoclinic structural model nor from possible impurities, and thus reinforcing the idea of them being intrinsic to the structure of the mineral, suggesting the necessity of a revisal of the commonly accepted structure of palygorskite.
      Graphical abstract image

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.006
      Issue No: Vol. 148 (2017)
       
  • Halloysite-based hybrid bionanocomposite hydrogels as potential drug
           delivery systems
    • Authors: Nooshin Sabbagh; Ali Akbari; Nasser Arsalani; Bagher Eftekhari-Sis; Hamed Hamishekar
      Pages: 48 - 55
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Nooshin Sabbagh, Ali Akbari, Nasser Arsalani, Bagher Eftekhari-Sis, Hamed Hamishekar
      In this investigation, the preparation of novel Halloysite-based chitosan/oxidized starch (Hal/CTS/OSR) Hybrid bionanocomposite hydrogels is described. The obtained hybrid hydrogels were characterized by using FT-IR, SEM, XRD, TGA and DTG techniques. In addition, the efficiency of hydrogels as drug delivery systems was studied. The results demonstrated that depending on experimental parameters, such as the ratio of CTS/OSR, and the type of Hal nanotubes (modified or unmodified), the hydrogel properties can be affected and modulated significantly. 74.3%, 71.2% and 69.45% MTZ release were observed for CTS/OSR/mHal 10, CTS/OSR and CTS/OSR/Hal 10 respectively.
      Graphical abstract image

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.009
      Issue No: Vol. 148 (2017)
       
  • Removal of Pb2+ ions from aqueous solutions by fixed-BED column using a
           
    • Authors: Oscar Allahdin; Joseph Mabingui; Michel Wartel; Abdel Boughriet
      Pages: 56 - 67
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Oscar Allahdin, Joseph Mabingui, Michel Wartel, Abdel Boughriet
      Brick was pre-activated with HCl and subsequently coated with ferrihydrite. To assess the potential of this modified brick for Pb2+ removal, adsorption experiments were conducted in a fixed-bed continuous-flow column system. The prediction of breakthrough curves was obtained by using the Thomas model. MINTEQ computations revealed that Pb2+ and Pb(OH)+ are the major species present in the column solution. Potentiometric analysis and electrophoretic mobility measurements provided strong evidence of the surface basicity of coated brick due to the existence of sodic negatively charged sites: >SO− Na+ with SFe; Si; or Al. Using Environmental Scanning Electron Microscopy (ESEM) equipped with an Energy Dispersive X-Ray Spectroscopy (EDS), micro-analyses showed clearly that Na atoms present in coated brick are preferentially bound to ferrihydrite specimens. The ESEM/EDS technique allowed to further highlight discrete PbFe combinations and to contend that Pb2+ ions are better adsorbed onto Fe-rich aggregates than onto SiO2 and alumino-silicates (clays). Before the breakthrough time, the pH in the effluent solution was found to be dependent upon the electrokinetic characteristics of coated brick. After this time, the pH was instead governed by the acidity of not adsorbed lead(II). To support this, simulation calculations relative to the pH evolution in the column medium were made. The addition of a background electrolyte (Na+ NO3 −) led nevertheless to a weaker adsorption capacity of Pb2+ on coated brick, because positively charged Na ion competed favorably at the expense of lead(II) via electrostatic attraction forces.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.002
      Issue No: Vol. 148 (2017)
       
  • Synergistic stabilization of Pickering emulsions by in situ modification
           of kaolinite with non ionic surfactant
    • Authors: Trivikram Nallamilli; Madivala G. Basavaraj
      Pages: 68 - 76
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Trivikram Nallamilli, Madivala G. Basavaraj
      Synergistic stabilization of decane/water emulsions with a combination of kaolinite and non ionic surfactant SPAN-80 is explored. Pure kaolinite being charged and very hydrophilic is a poor stabilizer of emulsions even when sufficient quantity of salt is added to screen electrical double layer interactions. However, the hydrophobicity (via. contact angle) of kaolinite can be tuned with increasing concentration of SPAN-80 leading to very stable O/W emulsions when both kaolinite and SPAN-80 are used. This is due to increase in hydrophobicity of kaolinite particles due to surfactant adsorption which enables them to get adsorbed at oil/water interface more efficiently. Adsorption of kaolinite at emulsion droplets is demonstrated through fluorescently labeled kaolinite. Emulsions phase inverted from O/W to W/O at very high concentrations of surfactant. This phase inversion is due to competitive adsorption of excess unadsorbed surfactant. Other general features such as the effect of salt, pH, oil/water ratio on emulsion formation, stability, type and droplet size has been studied.
      Graphical abstract image

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.07.038
      Issue No: Vol. 148 (2017)
       
  • A gradient Laponite-crosslinked nanocomposite hydrogel with anisotropic
           stress and thermo-response
    • Authors: Yun Tan; Shimei Xu; Ronglan Wu; Juan Du; Jilong Sang; Jide Wang
      Pages: 77 - 82
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Yun Tan, Shimei Xu, Ronglan Wu, Juan Du, Jilong Sang, Jide Wang
      A gradient Laponite (Lap)-crosslinked nanocomposite (NC) hydrogel was fabricated by a facile electrophoresis method based on colloidal property of Lap, as well as interaction between Lap and thermo-responsive monomers. TGA, FTIR, SEM and TEM were used to characterize the gradient structure. The gradient NC hydrogel exhibited both gradient distribution of Lap and thermo-responsive polymers under the induction of direct current electric field (DC-EF). The gradient NC hydrogel showed anisotropic mechanical properties and gradient thermo-response along the direction of DC-EF. The mechanical strength of the gradient NC hydrogel increased by 38% compared with isotropic NC hydrogel. An increase in Lap content would improve the mechanical property and extend the strength range in different locations of the gradient hydrogel. Meanwhile, the compressive strength of the gradient NC hydrogels can also be adjusted in the range of 117–1774kPa by changing the concentration of Lap. The work enabled the gradient NC hydrogels to apply in the field of tissue engineering and provided a new insight into development of novel bionic materials.
      Graphical abstract image

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.004
      Issue No: Vol. 148 (2017)
       
  • Laboratory investigations on the swelling behavior of composite expansive
           clays stabilized with shallow and deep clay-cement mixing methods
    • Authors: Pitthaya Jamsawang; Nuttapong Nuansrithong; Panich Voottipruex; Smith Songpiriyakij; Pornkasem Jongpradist
      Pages: 83 - 94
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Pitthaya Jamsawang, Nuttapong Nuansrithong, Panich Voottipruex, Smith Songpiriyakij, Pornkasem Jongpradist
      Expansive clays are considered as problematic due to their high swelling potential. Shallow and deep clay-cement mixing can be used in the creation of the composite materials to improve the swelling behavior of such clays. This research aims to observe the swelling characteristics of expansive clays stabilized by shallow and deep cement mixing methods using composite free swelling tests in the laboratory. Bentonite-kaolin mixtures were used as base clays to create high, medium and low degrees of swelling potentials of the expansive clays. The results show that improvements in the volume ratio (V r), which is a combination of the thickness ratio (T r) and improvement area ratio (a r), affect the overall swelling behavior of the composite expansive clays. This study proposes correlations between the maximum swelling potentials, swelling rate and secondary swelling rate versus V r. The microstructure and mineralogy of unstabilized and stabilized specimens were analyzed by X-ray diffractometry and scanning electron microscopy. The results show that the maximum swelling potentials of the composite clays are a function of the reflection intensities of calcium silicate hydrate and montmorillonite after stabilization.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.013
      Issue No: Vol. 148 (2017)
       
  • Sepiolite as a feed supplement for broilers
    • Authors: S. Yalçın; S. Yalçın; E.S. Gebeş; A. Şahin; H.M. Duyum; F. Escribano; A. Ceylan
      Pages: 95 - 102
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): S. Yalçın, S. Yalçın, E.S. Gebeş, A. Şahin, H.M. Duyum, F. Escribano, A. Ceylan
      This study was planned to determine the importance of sepiolite in broiler nutrition. For this purpose a total of 180 Ross 308 male broiler chicks aged one day were used. One control group and two treatment groups were designed for 6weeks of experimental period. Each group was divided into 10 replicates of 6 chicks each in pens. Sepiolite (Exal T®, Tolsa Turkey) was added at the level of 0, 1 and 2% to the diets of control group and the first and the second treatment groups as topdressed, respectively. Sepiolite supplementation at the level of 1% improved final body weight, weight gain and feed efficiency. Dietary treatments did not affect feed intake, gut pH, carcass yield, relative weight of the liver, kidney, spleen, bursa of Fabricius and carcass parts, footpad score, excreta and litter characteristics. Tibia characteristics, blood parameters and breast meat characteristics were not affected by the usage of sepiolite. Relative weight of the abdominal fat and ileal digesta viscosity were reduced and duodenal villus height, ileal digestibility of dry matter, organic matter and crude protein was increased with the usage of 1% sepiolite. It is concluded that dietary supplementation with 1% sepiolite was an effective feed additive for broiler feeding due to its beneficial effects on growth performance, abdominal fat percentage, ileal digesta viscosity, duodenal villus height and ileal digestibility.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.007
      Issue No: Vol. 148 (2017)
       
  • Preparation of functionalized kaolinite/epoxy resin nanocomposites with
           enhanced thermal properties
    • Authors: Linna Su; Xiaoliang Zeng; Hongping He; Qi Tao; Sridhar Komarneni
      Pages: 103 - 108
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Linna Su, Xiaoliang Zeng, Hongping He, Qi Tao, Sridhar Komarneni
      In this study, kaolinite/epoxy resin nanocomposites were fabricated using functionalized kaolinite (KGS) as filler. The KGS was prepared by silylation of 3-aminopropyltriethoxysilane onto the surface of mechanically ground kaolinite. The addition of KGS into epoxy resin matrix improved the storage modulus and glass-transition temperature, compared to those of epoxy resin nanocomposites filled with raw kaolinite. Furthermore, with the increase of KGS loading, the coefficient of thermal expansion decreased gradually, and the dielectric constant slightly increased when compared to that of pure epoxy resin. The presence of kaolinite led to an improvement in the water resistance property of kaolinite/epoxy resin nanocomposites. This research provided guidance to construct high-performance kaolinite/epoxy resin nanocomposites.
      Graphical abstract image

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.017
      Issue No: Vol. 148 (2017)
       
  • Effect of slag and calcium carbonate addition on the development of
           geopolymer from indurated laterite
    • Authors: Patrick N. Lemougna; Kai-tuo Wang; Qing Tang; E. Kamseu; N. Billong; U. Chinje Melo; Xue-min Cui
      Pages: 109 - 117
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Patrick N. Lemougna, Kai-tuo Wang, Qing Tang, E. Kamseu, N. Billong, U. Chinje Melo, Xue-min Cui
      This paper reports the development of inorganic polymers from laterite, for a potential use at least as non-load bearing building materials. The effect of blending laterite with Ground Granulated Blast Furnace Slag (GGBS) and calcite (CaCO3) was investigated. Laterite was substituted by calcite at 2 to 20% in mass and by GGBS at 5 to 50% in mass. X-ray diffraction, Fourier Transform Infrared spectroscopy and differential thermal analysis evidenced the presence of kaolinite, hematite, and quartz minerals in the laterite. Sodium silicate solutions of modulus ranging from 1.6 to 2.2 were used to prepare inorganic polymers from laterite that had been thermally treated at 700°C. The strength increased with the reduction of the modulus of the activating solution, achieving a 28days maximum compressive strength of 36MPa at 25°C. The substitution of laterite by calcite was found to have little effect on the compressive strength meanwhile the substitution of laterite by slag was beneficial for strength development, mainly from 20% substitution, achieving a 28days compressive strength of 65MPa at 50% slag. Mercury Intrusion Porosity and Scanning Electron Microscopy analysis evidenced a better refinement in microstructure with slag addition in the system. The results of compressive strength were found to be in agreement with ASTM C216–17 standard for building bricks, suggesting a potential interest for the valorization of laterite and blended laterite/slag in the development of at least non-load bearing building materials, using geopolymer technology.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.015
      Issue No: Vol. 148 (2017)
       
  • Adhesion force measurements between deep-sea soil particles and metals by
           in situ AFM
    • Authors: W.B. Ma; C.L. Qi; Q. Liu; Y.H. Ding; W. Zhu
      Pages: 118 - 122
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): W.B. Ma, C.L. Qi, Q. Liu, Y.H. Ding, W. Zhu
      Deep-sea soil particles collected from the Pacific C-C area were successfully immobilized on commercial AFM cantilever by a home-made test apparatus. Using this modified probe, adhesion force distribution between the deep-sea soil particle and four metals was measured by in situ AFM. The factors influencing the adhesion force were investigated. The adhesion forces between soil particles and the metal surface were ranked in an order of aluminum alloy (5052)<titanium alloy (STi80)<pure titanium (TA2)<titanium alloy (TC4) under same roughness, indicating the self-cleaning property of 5052 is better than the others. Furthermore, the results suggest the adhesion force decreases as the roughness increases within a certain range. The adhesion forces were determined by the surface energy and the contact radius based on JKR contact model.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.08.011
      Issue No: Vol. 148 (2017)
       
  • Drug release material hosted by natural montmorillonite with proper
           modification
    • Authors: Limei Wu; Guocheng Lv; Meng Liu; Danyu Wang
      Pages: 123 - 130
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Limei Wu, Guocheng Lv, Meng Liu, Danyu Wang
      In developing new generations of coatings for drug and drug controlled release, there is a need for self-assembled materials that provide controlled sequential release of multiple therapeutics, while provide a tunable approach to time dependence and the potential for sequential or staged release. Herein, we demonstrated the ability to develop a self-assembled, in ciprofloxacin intercalated montmorillonite (CIP-Mt), the release rate and amount of interlayer ciprofloxacin (CIP) could be controlled by modifying the layer charge of montmorillonite (Mt). Compared with common sustained release materials, this composite had better effect on antibacterial and disinfection. The CIP-Mt system effectively blocked diffusion-based release, leading to approximately 50% reduction in bolus doses and 10-fold increase in the release timescale. Mt was a non-toxic and non-polluting sustained release material, could be applied to drug release research, and the release rate and time of its interlayer CIP can be controlled by modifying layer charge.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.07.034
      Issue No: Vol. 148 (2017)
       
  • Synthesis of porous bentonite organoclay granule and its adsorption of
           tributyltin
    • Authors: Jianhua Du; Sreenivasulu Chadalavada; Ravi Naidu
      Pages: 131 - 137
      Abstract: Publication date: November 2017
      Source:Applied Clay Science, Volume 148
      Author(s): Jianhua Du, Sreenivasulu Chadalavada, Ravi Naidu
      We report a new method to synthesise porous organoclay granules which is suitable for high flow rate wastewater treatment applications. Granulation process consists of three steps: mixing natural clay powder, fine coal dust and corn starch into a homogeneous mixture; granulating in a rotating tilted pan granulator by spraying water mist; and heat treatment firstly at 190°C for 30min to solidify and then calcined at 550°C for 4h to create pores. These procedures produced very strong porous clay granules with a crushing strength of 8.41N, the permeability of the granules was 1.56×106 mD and hydraulic conductivity of 1.5cm/s. To further enhance the adsorption performance, the granules were later modified by surfactant hexadecyltrimethylammonium bromide (HDTMA) and tested for its adsorption capacity for removing toxic antifouling agent tributyltin (TBT) at high flow rate. It was found that cationic HDTMA modification enhanced the TBT adsorption capacity by 20%. This new granulation method allows the mass production of porous organo clay granules while the porous granular clay is also a good substrate for coating material such as nano sized zero-valent iron to further extent its application.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.07.033
      Issue No: Vol. 148 (2017)
       
  • Inorganically modified clay minerals: Preparation, characterization, and
           arsenic adsorption in contaminated water and soil
    • Authors: Raj Mukhopadhyay; K.M. Manjaiah; S.C. Datta; R.K. Yadav; Binoy Sarkar
      Pages: 1 - 10
      Abstract: Publication date: October 2017
      Source:Applied Clay Science, Volume 147
      Author(s): Raj Mukhopadhyay, K.M. Manjaiah, S.C. Datta, R.K. Yadav, Binoy Sarkar
      The use of modified clay minerals for adsorbing arsenic (As) in contaminated soils is an underexplored area of research. The adsorption behavior of As onto inorganically modified smectite and kaolinite both in aqueous and soil media was studied. X-ray diffraction, infra-red spectroscopy, scanning and transmission electron microscopy studies confirmed successful modification of smectite through Fe-exchange and Ti-pillaring, and kaolinite through phosphate binding. The modified smectites were more efficient than phosphate-bound kaolinite in adsorbing As both in water and soil systems. Kinetic study revealed that the clay products reached adsorption equilibrium within 3h, and the data well fitted to the power function and simple Elovich equation (R2 >0.90). The Freundlich isotherm model best described the As adsorption data (R2 >0.86) of the modified clay products in both the systems. The Ti-pillared smectite exhibited the highest As adsorption capacity (156.54μgg−1) in the aqueous medium, while the Fe-exchanged smectite was the best material in the soil system (115.63μgg−1). The partition coefficient (Kd) and adsorption efficiency (%) data also maintained the similar trend. Precipitation of As and binuclear complex formation also took place in the soil system which made the metalloid non-labile as the time passed. The inorganically modified clay products reported here hold a great potential to adsorb As in contaminated groundwater, drinking water as well as soil.

      PubDate: 2017-08-03T10:13:25Z
      DOI: 10.1016/j.clay.2017.07.017
      Issue No: Vol. 147 (2017)
       
  • Pozzolanic activity of calcined halloysite-rich kaolinitic clays
    • Authors: Alejandra Tironi; Fernanda Cravero; Alberto N. Scian; Edgardo F. Irassar
      Pages: 11 - 18
      Abstract: Publication date: October 2017
      Source:Applied Clay Science, Volume 147
      Author(s): Alejandra Tironi, Fernanda Cravero, Alberto N. Scian, Edgardo F. Irassar
      The aim of this study is to determine the pozzolanic activity of clays with high content of halloysite/kaolinite, and to evaluate the influence of halloysite/kaolinite ratio and halloysite morphology in the development of pozzolanic activity of the calcined clays. For this purpose, three different natural clays from Río Negro Province, Argentine, were selected and completely characterized. After calcined at 700°C and ground to 80% of particle size <45μm, pozzolanic activity was determined using the electrical conductivity test, the Frattini test and the compressive strength index. Results show that all calcined clays are classified as high reactive pozzolana. The presence of kaolinite and spheroidal halloysite exerts great influence at early ages; while tubular halloysite has greater influence in the pozzolanic activity and the compressive strength of mortars at later ages.
      Graphical abstract image

      PubDate: 2017-08-03T10:13:25Z
      DOI: 10.1016/j.clay.2017.07.018
      Issue No: Vol. 147 (2017)
       
  • BiOCl-montmorillonite as a photocatalyst for highly efficient removal of
           Rhodamine B and Orange G: Importance of the acidity and dissolved oxygen
    • Authors: Chengqun Xu; Feng Long Gu; Honghai Wu
      Pages: 28 - 35
      Abstract: Publication date: October 2017
      Source:Applied Clay Science, Volume 147
      Author(s): Chengqun Xu, Feng Long Gu, Honghai Wu
      A BiOCl-Mt material assembled from BiOCl and Na-montmorillonite (Na-Mt) was characterized by XRD, FT-IR, TEM, XPS and UV–vis DRS. Na-Mt was clearly demonstrated to be capable of improving BiOCl's photocatalytic performance. The focus was placed on the evaluation of BiOCl-Mt in the terms of photocatalytic activity for cationic Rhodamine B (RhB) and anionic Orange G (OG). Both can be removed more efficiently using BiOCl-Mt compared with pure BiOCl under ultraviolet light irradiation. Although h vb + and O2 − are the two primary reactive species, the improved photocatalytic degradation performance is primarily attributed to the enhanced separation of photogenerated charge carriers in the catalyst. The Bronsted acidity derived from montmorillonite acid sites and the dissolved oxygen in the solution are capable of promoting dye photocatalysis because they effectively capture the photogenerated electrons. Under optimized conditions, TOC mineralization with rates of 82.3% for RhB and 85.9% for OG was obtained in a BiOCl-Mt catalysed photocatalysis process. The mechanism responsible for the oxidative decomposition of the two different dyes is primarily hole-driven. BiOCl-Mt was stable during the process, with its structures remaining almost unchanged after it was recycled three times. Therefore, BiOCl-Mt will have a promising worldwide application in dye-containing wastewater treatment.
      Graphical abstract image

      PubDate: 2017-08-03T10:13:25Z
      DOI: 10.1016/j.clay.2017.07.025
      Issue No: Vol. 147 (2017)
       
  • Mercury removal from coal combustion flue gas by modified palygorskite
           adsorbents
    • Authors: Huan Liu; Jianping Yang; Chong Tian; Yongchun Zhao; Junying Zhang
      Pages: 36 - 43
      Abstract: Publication date: October 2017
      Source:Applied Clay Science, Volume 147
      Author(s): Huan Liu, Jianping Yang, Chong Tian, Yongchun Zhao, Junying Zhang
      Several modified adsorbents were developed by impregnating palygorskite (Pal) with the active substances CuCl2, CuBr2, NaBr, sulfur (S), MnO2 and Co3O4, which were used to conduct experiments via a bench-scale fixed-bed reactor system in simulated flue gas for evaluating their elemental mercury removal capacity. In addition, a variety of characterization methods were applied to understand the physicochemical properties of these adsorbents. Furthermore, adsorbents, namely, CuCl2/CuBr2-impregnated Pal (Cu-Pal), were chosen for deep exploration under various gas conditions. The results showed that the mercury removal capability of Pal was greatly improved after impregnation. At 120°C in pure N2, the mercury removal efficiency of the adsorbents modified by CuCl2 and CuBr2 could reach 90.9% and 95.2%, respectively, while it could be >80% for the adsorbents modified by the others. The overall trend showed that O2 and HCl were beneficial to increasing the mercury removal efficiency of Cu-Pal. To be specific, for CuCl2-Pal and CuBr2-Pal, when adding in 8% O2, their efficiencies could be increased by 6.6% and 1.9% respectively, while 50ppm HCl increased their efficiencies by 2.8% and 2.1%, respectively. Different from O2 and HCl, SO2 and NO had negative effects. The removal efficiencies could be reduced by 6.5% for CuCl2-Pal and 4.7% for CuBr2-Pal with 1200ppm SO2, while they could be reduced by 4.2% and 2.6% with 300ppm NO. Compared with CuCl2-Pal, CuBr2-Pal performed better. Combined with the characterization results, Cu2+ was reduced to Cu+ and halogen migrated into new compounds on the surface of Cu-Pal after reaction. Eventually, the mercury removal mechanism of Cu-Pal was analysed and proposed.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.05.006
      Issue No: Vol. 147 (2017)
       
  • More aggressive sequential extraction procedure to access stable forms of
           Pb and As in clay minerals of soils
    • Authors: A.H. Batista; V.F. Melo; A.W. Rate; A. Uhlmann; R. Gilkes
      Pages: 44 - 53
      Abstract: Publication date: October 2017
      Source:Applied Clay Science, Volume 147
      Author(s): A.H. Batista, V.F. Melo, A.W. Rate, A. Uhlmann, R. Gilkes
      Lead (Pb) and arsenic (As) are potentially toxic in their most reactive forms, but can also occur as structural and specifically adsorbed (more stable forms) ions on clay minerals. Due to their lower mobility in soils, structural and specific adsorbed forms are usually neglected in environmental studies, but can be important, for example, in geochemistry researches. The aim of this study was to evaluate the occurrence of stable forms of Pb and As in the clay fraction of soils in a region rich in Pb ore (galena) in south Brazil using more aggressive sequential extractions (boiling 5molL−1 NaOH, successive citrate-bicarbonate-dithionite steps, and sodium bisulfate fusion). X-ray diffraction was used to follow possible mineralogical variations after each sequential extraction. We sampled soils from two areas rich in trace elements, with high occurrence of mineral deposits (PbS) in carbonate and phyllite/mica schist rocks. A reference soil formed on mineralized granite/gneiss was also sampled. In different mineral phases of the sequential extraction, preferential association of Pb with minerals extracted by 5molL−1 NaOH (kaolinite, low crystalline smectite and precipitated of Pb-S and Pb-P) was observed. In soils formed from parent materials at the phyllite/mica schist metamorphic stage, Pb contents solubilized by NaOH were extremely high (maximum >28,000mgkg−1). Lead exists in the mineral structure, such as Fe oxides, as result of the isomorphic substitution of Fe for Pb. Manganese oxides were also important host of Pb in the clay fraction. The largest As contents occurred at greater depth in the soil. The more aggressive sequential extraction procedure is more suitable to estimate the structural and specific adsorbed forms of Pb and As in clay minerals.

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.05.020
      Issue No: Vol. 147 (2017)
       
  • Cr(VI) removal from aqueous solutions using aluminosilicate minerals in
           their Pb-exchanged forms
    • Authors: Athanasios Georgios Thanos; Evina Katsou; Simos Malamis; Vasilis Drakopoulos; Pantelis Paschalakis; Evangelia Angelos Pavlatou; Katherine Joanne Haralambous
      Pages: 54 - 62
      Abstract: Publication date: October 2017
      Source:Applied Clay Science, Volume 147
      Author(s): Athanasios Georgios Thanos, Evina Katsou, Simos Malamis, Vasilis Drakopoulos, Pantelis Paschalakis, Evangelia Angelos Pavlatou, Katherine Joanne Haralambous
      This work investigated the removal of Cr(VI) from aqueous solutions by employing Pb-modified zeolite, vermiculite and perlite as adsorbents. Natural zeolite and vermiculite exhibited high Pb2+ adsorption (~80% of the total Pb2+ concentration in solution), while perlite resulted in low lead adsorption (21%). Subsequently, the Pb-modified zeolite and vermiculite exhibited high Cr(VI) adsorption. The maximum Cr(VI) adsorption capacity as predicted by the Langmuir isotherm was 18.9mgg−1 for zeolite and 23.0mgg−1 for vermiculite. Langmuir was the isotherm equation that best fitted the experimental data. In terms of kinetics the Elovich equation represented the best fit to Cr(VI) adsorption on the studied modified minerals. The lowest mineral concentration that was tested (10gL−1) resulted in the highest solid phase equilibrium concentration. Desorption experiments were not effective since the desorption percent achieved with NaCl solution was very low (4–6%). Cr(VI) removal using Pb-modified minerals can be applied in the successive treatment of industrial wastewater first for lead and then for Cr(VI) removal.
      Graphical abstract image

      PubDate: 2017-09-02T02:52:28Z
      DOI: 10.1016/j.clay.2017.05.040
      Issue No: Vol. 147 (2017)
       
  • Influence of dehydration on the dielectric and structural properties of
           organically modified montmorillonite and halloysite nanotubes
    • Authors: Kadlec
      Abstract: Publication date: October 2017
      Source:Applied Clay Science, Volume 147
      Author(s): R. Polanský, P. Kadlec, Z. Kolská, V. Švorčík
      The dielectric behaviours of organically modified montmorillonite (Cloisite-20) and nanosized tubular halloysite (Dragonite-HP) were investigated using broadband dielectric spectroscopy (BDS) under dehydration conditions up to 200°C. The thermal and structural properties of both tested clay minerals were also initially examined in the as-received and dehydrated samples. Dragonite-HP was shown to lose 2.2 mass% of the adsorbed and interlayer water up to 200°C. The dehydration of Dragonite-HP also caused the tightly connected tubular layers to unfold, thereby increasing the specific surface area and the total pore volume. Cloisite-20 lost only 1.1 mass% of its adsorbed water during dehydration due to the presence of an organic modifier, bis(hydrogenated tallow alkyl)dimethyl. Its presence led to decreases in the specific surface area and total pore volume of Cloisite-20 relative to those of pristine montmorillonite. BDS revealed that the dielectric constant (ε') and dissipation factor (tan δ) of the thermally treated Dragonite-HP increased and that the volume resistivity (ρ v ) decreased within one order of magnitude in the temperature range of −40 to 90°C. In contrast, the ε' of the thermally treated Cloisite-20 increased by two orders of magnitude, the tan δ increased by more than three orders of magnitude, and the ρ v decreased by five orders of magnitude. The values of ε', tan δ and ρ v measured via BDS demonstrate that the dielectric properties of Dragonite-HP at a standard industrial frequency of 50Hz and under a typical operating temperature range are more advantageous than those of Cloisite-20. This finding is very promising for the possible use of Dragonite-HP as a nanofiller for clay/polymer nanocomposites intended for cable core insulation manufacturing.

      PubDate: 2017-08-03T10:13:25Z
       
 
 
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