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EARTH SCIENCES (470 journals)                  1 2 3 | Last

Showing 1 - 200 of 371 Journals sorted alphabetically
Acta Geochimica     Hybrid Journal   (Followers: 3)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 1)
Acta Geodaetica et Geophysica Hungarica     Full-text available via subscription   (Followers: 2)
Acta Geophysica     Open Access   (Followers: 6)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3)
Advances in High Energy Physics     Open Access   (Followers: 21)
Advances In Physics     Hybrid Journal   (Followers: 18)
Aeolian Research     Hybrid Journal   (Followers: 5)
African Journal of Aquatic Science     Hybrid Journal   (Followers: 12)
Algological Studies     Full-text available via subscription   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 3)
AMBIO     Hybrid Journal   (Followers: 13)
Anadolu University Journal of Science and Technology     Open Access  
Anales del Instituto de la Patagonia     Open Access   (Followers: 1)
Andean geology     Open Access   (Followers: 13)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3)
Annales UMCS, Geographia, Geologia, Mineralogia et Petrographia     Open Access  
Annals of Geophysics     Full-text available via subscription   (Followers: 12)
Annals of GIS     Hybrid Journal   (Followers: 19)
Annals of Glaciology     Full-text available via subscription   (Followers: 3)
Annual Review of Marine Science     Full-text available via subscription   (Followers: 10)
Anthropocene     Hybrid Journal   (Followers: 3)
Anthropocene Review     Hybrid Journal   (Followers: 4)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Geochemistry     Hybrid Journal   (Followers: 11)
Applied Geomatics     Hybrid Journal   (Followers: 3)
Applied Geophysics     Hybrid Journal   (Followers: 7)
Applied Ocean Research     Hybrid Journal   (Followers: 4)
Applied Petrochemical Research     Open Access   (Followers: 2)
Applied Remote Sensing Journal     Open Access   (Followers: 33)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 34)
Arctic Science     Open Access   (Followers: 6)
Arctic, Antarctic, and Alpine Research     Full-text available via subscription   (Followers: 10)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 16)
Asia-Pacific Journal of Atmospheric Sciences     Hybrid Journal   (Followers: 20)
Asian Journal of Earth Sciences     Open Access   (Followers: 20)
Asian Review of Environmental and Earth Sciences     Open Access   (Followers: 1)
Atlantic Geology : Journal of the Atlantic Geoscience Society / Atlantic Geology : revue de la Société Géoscientifique de l'Atlantique     Full-text available via subscription   (Followers: 10)
Atmosphere-Ocean     Full-text available via subscription   (Followers: 12)
Atmospheric and Climate Sciences     Open Access   (Followers: 25)
Australian Journal of Earth Sciences: An International Geoscience Journal of the Geological Society of Australia     Hybrid Journal   (Followers: 11)
Boletim de Ciências Geodésicas     Open Access  
Boletín de Ciencias de la Tierra     Open Access   (Followers: 1)
Boreas: An International Journal of Quaternary Research     Hybrid Journal   (Followers: 10)
Bragantia     Open Access   (Followers: 2)
Bulletin of Earthquake Engineering     Hybrid Journal   (Followers: 10)
Bulletin of Geosciences     Open Access   (Followers: 8)
Bulletin of the Lebedev Physics Institute     Hybrid Journal   (Followers: 1)
Bulletin of the Seismological Society of America     Full-text available via subscription   (Followers: 21)
Bulletin of Volcanology     Hybrid Journal   (Followers: 17)
Cadernos de Geociências     Open Access  
Canadian Journal of Plant Science     Full-text available via subscription   (Followers: 15)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Canadian Water Resources Journal     Hybrid Journal   (Followers: 20)
Carbonates and Evaporites     Hybrid Journal   (Followers: 3)
CATENA     Hybrid Journal   (Followers: 4)
Chemical Geology     Hybrid Journal   (Followers: 15)
Chemie der Erde - Geochemistry     Hybrid Journal   (Followers: 4)
Chinese Geographical Science     Hybrid Journal   (Followers: 5)
Chinese Journal of Oceanology and Limnology     Hybrid Journal   (Followers: 3)
Ciencias Espaciales     Open Access  
Climate and Development     Hybrid Journal   (Followers: 12)
Coastal Management     Hybrid Journal   (Followers: 24)
Cogent Geoscience     Open Access  
Comptes Rendus Geoscience     Full-text available via subscription   (Followers: 8)
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Mathematics and Mathematical Physics     Hybrid Journal   (Followers: 1)
Computers and Geotechnics     Hybrid Journal   (Followers: 8)
Contemporary Trends in Geoscience     Open Access   (Followers: 3)
Continental Shelf Research     Hybrid Journal   (Followers: 8)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 9)
Contributions to Plasma Physics     Hybrid Journal   (Followers: 3)
Coral Reefs     Hybrid Journal   (Followers: 16)
Cretaceous Research     Hybrid Journal   (Followers: 6)
Cybergeo : European Journal of Geography     Open Access   (Followers: 5)
Depositional Record     Open Access  
Developments in Geotectonics     Full-text available via subscription   (Followers: 3)
Developments in Quaternary Science     Full-text available via subscription   (Followers: 3)
Développement durable et territoires     Open Access   (Followers: 3)
Diatom Research     Hybrid Journal   (Followers: 1)
Doklady Physics     Hybrid Journal   (Followers: 1)
Dynamics of Atmospheres and Oceans     Hybrid Journal   (Followers: 10)
E&S Engineering and Science     Open Access  
E3S Web of Conferences     Open Access  
Earth and Planetary Science Letters     Hybrid Journal   (Followers: 98)
Earth and Space Science     Open Access   (Followers: 10)
Earth Interactions     Full-text available via subscription   (Followers: 11)
Earth Science Research     Open Access   (Followers: 6)
Earth Sciences Research Journal     Open Access  
Earth Surface Dynamics (ESurf)     Open Access   (Followers: 4)
Earth Surface Processes and Landforms     Hybrid Journal   (Followers: 19)
Earth System Dynamics     Open Access   (Followers: 6)
Earth System Dynamics Discussions     Open Access   (Followers: 4)
Earth's Future     Open Access   (Followers: 1)
Earth, Planets and Space     Open Access   (Followers: 68)
Earthquake Engineering and Engineering Vibration     Hybrid Journal   (Followers: 6)
Earthquake Science     Hybrid Journal   (Followers: 9)
Earthquake Spectra     Full-text available via subscription   (Followers: 17)
Ecohydrology     Hybrid Journal   (Followers: 10)
Ecological Questions     Open Access   (Followers: 7)
Electromagnetics     Hybrid Journal   (Followers: 4)
Energy Efficiency     Hybrid Journal   (Followers: 11)
Energy Exploration & Exploitation     Full-text available via subscription   (Followers: 4)
Environmental Earth Sciences     Hybrid Journal   (Followers: 22)
Environmental Geology     Hybrid Journal   (Followers: 20)
Environmental Geosciences     Full-text available via subscription   (Followers: 3)
Environmental Geotechnics     Hybrid Journal   (Followers: 3)
Erwerbs-Obstbau     Hybrid Journal  
Estuaries and Coasts     Hybrid Journal   (Followers: 17)
Estuarine, Coastal and Shelf Science     Hybrid Journal   (Followers: 34)
Estudios Geográficos     Open Access  
European Journal of Mineralogy     Full-text available via subscription   (Followers: 12)
Exploration Geophysics     Hybrid Journal   (Followers: 4)
Facies     Hybrid Journal   (Followers: 9)
Fieldiana Life and Earth Sciences     Full-text available via subscription   (Followers: 1)
Física de la Tierra     Open Access  
Folia Musei rerum naturalium Bohemiae occidentalis. Geologica et Paleobiologica     Open Access  
Folia Quaternaria     Open Access  
Forestry Chronicle     Full-text available via subscription   (Followers: 10)
Frontiers in Earth Science     Open Access   (Followers: 5)
Frontiers in Geotechnical Engineering     Open Access   (Followers: 2)
Frontiers of Earth Science     Hybrid Journal   (Followers: 8)
Fundamental and Applied Limnology / Archiv für Hydrobiologie     Full-text available via subscription   (Followers: 4)
GEM - International Journal on Geomathematics     Hybrid Journal   (Followers: 1)
Geo-Marine Letters     Hybrid Journal   (Followers: 7)
Geoacta     Open Access   (Followers: 4)
Geobiology     Hybrid Journal   (Followers: 8)
Geocarto International     Hybrid Journal   (Followers: 22)
Geochemical Perspectives     Hybrid Journal  
Geochemistry : Exploration, Environment, Analysis     Hybrid Journal   (Followers: 7)
Geochemistry, Geophysics, Geosystems     Full-text available via subscription   (Followers: 25)
Geochimica et Cosmochimica Acta     Hybrid Journal   (Followers: 43)
Geochronometria     Hybrid Journal   (Followers: 3)
Geoderma Regional : The International Journal for Regional Soil Research     Full-text available via subscription   (Followers: 3)
Geodinamica Acta     Hybrid Journal   (Followers: 3)
Geodynamics & Tectonophysics     Open Access   (Followers: 1)
Geoenvironmental Disasters     Open Access   (Followers: 3)
Geofluids     Hybrid Journal   (Followers: 4)
Geoforum     Hybrid Journal   (Followers: 21)
Géographie physique et Quaternaire     Full-text available via subscription   (Followers: 1)
Geography and Natural Resources     Hybrid Journal   (Followers: 5)
Geoheritage     Hybrid Journal   (Followers: 1)
Geoinformatica Polonica : The Journal of Polish Academy of Arts and Sciences     Open Access  
Geoinformatics & Geostatistics     Hybrid Journal   (Followers: 8)
Geological Journal     Hybrid Journal   (Followers: 14)
Geology Today     Hybrid Journal   (Followers: 24)
Geomagnetism and Aeronomy     Hybrid Journal   (Followers: 3)
Geomatics, Natural Hazards and Risk     Hybrid Journal   (Followers: 9)
Geomechanics for Energy and the Environment     Full-text available via subscription  
GEOmedia     Open Access   (Followers: 1)
Geomorphology     Hybrid Journal   (Followers: 25)
Geophysical & Astrophysical Fluid Dynamics     Hybrid Journal   (Followers: 2)
Geophysical Journal International     Hybrid Journal   (Followers: 31)
Geophysical Prospecting     Hybrid Journal   (Followers: 7)
Geophysics     Full-text available via subscription   (Followers: 18)
GeoResJ     Hybrid Journal  
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards     Hybrid Journal   (Followers: 8)
Geoscience Canada : Journal of the Geological Association of Canada / Geoscience Canada : journal de l'Association Géologique du Canada     Full-text available via subscription   (Followers: 3)
Geoscience Data Journal     Open Access   (Followers: 2)
Geoscience Frontiers     Open Access   (Followers: 9)
Geoscience Letters     Open Access   (Followers: 1)
Geoscience Records     Open Access  
Geosciences     Open Access   (Followers: 2)
Geosciences Journal     Hybrid Journal   (Followers: 9)
Geoscientific Instrumentation, Methods and Data Systems     Open Access   (Followers: 4)
Geoscientific Model Development     Open Access   (Followers: 2)
Geostandards and Geoanalytical Research     Hybrid Journal   (Followers: 2)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotectonic Research     Full-text available via subscription   (Followers: 4)
Geotectonics     Hybrid Journal   (Followers: 7)
GISAP : Earth and Space Sciences     Open Access   (Followers: 2)
Glass Physics and Chemistry     Hybrid Journal   (Followers: 3)
Global and Planetary Change     Hybrid Journal   (Followers: 16)
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 12)
Gondwana Research     Hybrid Journal   (Followers: 6)
Grassland Science     Hybrid Journal   (Followers: 1)
Ground Water     Hybrid Journal   (Followers: 30)
Ground Water Monitoring & Remediation     Hybrid Journal   (Followers: 17)
Groundwater for Sustainable Development     Full-text available via subscription  
GSA Today     Partially Free  
Helgoland Marine Research     Open Access   (Followers: 3)
History of Geo- and Space Sciences     Open Access   (Followers: 4)
Hydrobiologia     Hybrid Journal   (Followers: 18)
Hydrogeology Journal     Hybrid Journal   (Followers: 16)
Hydrological Processes     Hybrid Journal   (Followers: 23)
Hydrology and Earth System Sciences     Open Access   (Followers: 26)
ICES Journal of Marine Science: Journal du Conseil     Hybrid Journal   (Followers: 53)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 11)
Indian Geotechnical Journal     Hybrid Journal   (Followers: 2)
Indonesian Journal on Geoscience     Open Access   (Followers: 2)
Interdisciplinary Environmental Review     Hybrid Journal   (Followers: 3)
International Geology Review     Hybrid Journal   (Followers: 12)
International Journal of Advanced Geosciences     Open Access  
International Journal of Advanced Remote Sensing and GIS     Open Access   (Followers: 33)
International Journal of Advancement in Earth and Enviromental Sciences     Open Access   (Followers: 3)
International Journal of Advancement in Remote Sensing, GIS, and Geography     Open Access   (Followers: 27)
International Journal of Applied Earth Observation and Geoinformation     Hybrid Journal   (Followers: 35)
International Journal of Coal Geology     Hybrid Journal   (Followers: 2)
International Journal of Disaster Risk Reduction     Hybrid Journal   (Followers: 11)

        1 2 3 | Last

Journal Cover Applied Clay Science
  [SJR: 0.826]   [H-I: 83]   [4 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0169-1317
   Published by Elsevier Homepage  [3039 journals]
  • Effect of temperature on swelling pressure and compressibility
           characteristics of soil
    • Authors: Ramakrishna Bag; Ahsan Rabbani
      Pages: 1 - 7
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Ramakrishna Bag, Ahsan Rabbani
      Clays are being used for several construction purposes particularly as waste isolation barrier and undergo several temperature and hydraulic condition during operational period. Clays may undergo large compression during the particular loading condition. Bentonite is highly swelling clay containing high amount of montmorillonite mineral is considered as barrier and backfilling material for high level radioactive waste disposal repositories. The present study investigates the effect of temperature on swelling pressure and compressibility behavior of divalent rich Indian bentonite (liquid limit =139%) from Bikaner, Rajasthan and effect of temperature on compressibility behavior of local soil (liquid limit =35%) from Rourkela. A new oedometer was designed and developed in-house to carry out consolidation and swelling pressure tests at various temperatures. Swelling pressures tests on compacted bentonite specimens of targeted dry density 1.6Mg/m3 were conducted under constant volume condition for the temperature range between 25 and 90°C. Consolidation tests at various temperatures between 25 and 90°C for both soils were carried out using distilled water as inundating fluid. The study revealed that with increase in temperature the swelling pressure and compressibility index of bentonite increased. However, effect of temperature on compressibility behavior of local soil was found to be minimum.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.10.043
      Issue No: Vol. 136 (2016)
  • The removal of molybdates and tungstates from aqueous solution by
    • Authors: Barbara Muir; Damian Andrunik; Jakub Hyla; Tomasz Bajda
      Pages: 8 - 17
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Barbara Muir, Damian Andrunik, Jakub Hyla, Tomasz Bajda
      This paper presents the results obtained when studying the removal of molybdate and tungstate anions from aqueous using organically modified montmorillonite. In batch experiments, the influence of pH, reaction time, the initial concentration of Mo and W, and the influence of the amount and type of surfactant was investigated. The modification of smectite with leads to the formation of an organo-mineral complex characterized by a positively-charged surface and a high sorption capacity in the removal of Mo(VI) and W(VI). The pH effect determining the possibility of Mo and W removal from the aqueous solution. In the pH range of 1–5, the sorption of Mo and W efficiency is very high, while at pH>5 sorption is limited or completely inhibited. DDTMA-smectite and DDDDMA-smectite were recognized as the best sorbents. With an increasing amount of surfactant used in modification process, the sorption efficiency increases. Molybdates are removed from solutions compared to tungstates to a much greater extent – maximum sorption capacities were 705 and 390mmol/kg, respectively. Kinetic studies indicated that maximum sorption capacity is achieved faster in the case of Mo than of W, and that the main sorption mechanisms are chemisorption and ion exchange.
      Graphical abstract image

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.006
      Issue No: Vol. 136 (2016)
  • Efficient preparation and application of palladium loaded montmorillonite
           as a reusable and effective heterogeneous catalyst for Suzuki
           cross-coupling reaction
    • Authors: Tian Li; Yanjun Liu; Feng-Shou Liu
      Pages: 18 - 25
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Tian Li, Yanjun Liu, Feng-Shou Liu
      The Na+ montmorillonite (Mt) was modified with l-cystine, and palladium was loaded via an ion-exchange reaction under microwave irradiation to obtain Pd@Mt. The entire process was conveniently carried out under mild reaction conditions in a matter of hours. The XRD, XPS and ICP-AES results confirmed the successful loading of palladium (0.55wt%). The so obtained Pd@Mt was subsequently explored as a catalyst for the Suzuki cross-coupling reaction and afforded the corresponding products in good to excellent yields for twenty reactants (in the range of 79–99%, only 3 reactants gave yields below 90%). The catalytic mechanism was investigated and discussed in detail. This supported catalyst could be easily recovered from the reaction mixture by simple filtration or centrifugation. Decreased palladium loss and improved reusability were achieved when the catalyst was recovered by filtration. Notably, this recovery method maintained the observed high yields, showing a >90% yield for the 6th run. Although palladium ions were reduced to Pd (0) in the cross-coupling reaction, only a small amount of aggregation was observed in the TEM images, where the diameters of the palladium particles on Mt were in nano scale.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.004
      Issue No: Vol. 136 (2016)
  • Effect of temperature on the rheological properties of neat aqueous
           Wyoming sodium bentonite dispersions
    • Authors: Zisis Vryzas; Vassilios C. Kelessidis; Lori Nalbantian; Vassilis Zaspalis; Dimitrios I. Gerogiorgis; Yiming Wubulikasimu
      Pages: 26 - 36
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Zisis Vryzas, Vassilios C. Kelessidis, Lori Nalbantian, Vassilis Zaspalis, Dimitrios I. Gerogiorgis, Yiming Wubulikasimu
      Temperature affects significantly the rheological behavior of neat water Wyoming Na-bentonite dispersions. The results of a very systematic study are presented regarding rheological measurements of 7% mass concentration at different temperatures, ranging between 25 and 80°C at atmospheric pressure. Higher temperature increased the shear stresses at low shear rates while the effect was much smaller at higher shear rates. The Herschel-Bulkley rheological model fitted extremely well all data. The yield stress increased linearly with temperature by almost three-fold, the flow consistency index decreased exponentially with temperature by almost five-fold and the flow behavior index increased by about 20%, tending towards the Newtonian value. At low shear rates (<100rpm corresponding to <170 1/s Newtonian shear rates), which represent very well the shear rates experienced by drilling fluids in the critical annulus region, all rheograms appeared fairly linear and the Bingham plastic model fitted well all data. The Bingham yield stress, from the low shear rate data, increased linearly with temperature, while the plastic viscosity decreased with temperature, in a manner very similar to the decrease of water viscosity with temperature. The plastic viscosity and Bingham yield stress data, from the low shear rate range, can be fitted well by an Arrhenius-type equation, with the activation energy for the plastic viscosity very similar to the activation energy for water viscosity, while for the Bingham yield stress, the activation energy is equal but opposite in sign to that of the plastic viscosity. A hypothesis is stated for the the observed linear increase of the yield stress with temperature, in the temperature range studied. One should be concerned when non-standard preparation and measurement procedures are followed which makes extremely difficult to understand any differences observed when reporting rheological data of water bentonite dispersions. A standard methodology is proposed, complementary to API, which can give very consistent results.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.007
      Issue No: Vol. 136 (2016)
  • Research on mineralogy and flotation for coal-series kaolin
    • Authors: Yuanyuan Liu; Shaomin Lei; Teng Huang; Mengjiao Ji; Yang Li; Yanming Fan
      Pages: 37 - 42
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Yuanyuan Liu, Shaomin Lei, Teng Huang, Mengjiao Ji, Yang Li, Yanming Fan
      The iron mineral was separated by froth flotation for the coal-series kaolin. The mineralogy of the coal-series kaolin was studied by several methods such as X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size distribution and SEM/EDS analyses. The mineralogy demonstrated that pyrite was the main occurrence of iron in the coal-series kaolin. The influence of grinding time and pH on the flotation was researched so as to determine the optimal flotation conditions. The results of froth flotation showed that the mass fraction of pyrite in kaolin concentrate was 0.11% at 1.12% pyrite in the flotation feed, and hence 90.72% of total pyrite was separated by froth flotation. The findings in this study suggest that the effective pyrite separation from coal-series kaolin was achieved by grinding moderate time and controlling pH weak acid and neutral.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.11.010
      Issue No: Vol. 136 (2016)
  • Investigation of the inhibition mechanism of the number of primary amine
           groups of alkylamines on the swelling of bentonite
    • Authors: Gang Xie; Pingya Luo; Mingyi Deng; Julin Su; Zheng Wang; Rui Gong; Junni Xie; Shunjie Deng; Qiang Duan
      Pages: 43 - 50
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Gang Xie, Pingya Luo, Mingyi Deng, Julin Su, Zheng Wang, Rui Gong, Junni Xie, Shunjie Deng, Qiang Duan
      The inhibition mechanism of alkylamines that have different numbers of primary amine groups adsorbed on sodium bentonite has been investigated using isothermal adsorption, adsorption kinetics, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental analysis (EA), cation exchange capacity (CEC), thermogravimetric analysis (TGA), linear expansion experiments and rolling recovery. The saturated adsorption capacity of alkylamines on sodium bentonite decreased with the increase in the number of primary amine groups. The adsorption rate constant increases rapidly with the increase in the number of primary amine groups on the premise that they are both water-soluble and hydrophobic. A flat-lying monolayer of each alkylamine was intercalated, replacing sodium ions in the interlayer and becoming firmly embedded in the interlayer space of sodium bentonite between the primary amine groups and silicon-oxygen tetrahedra. As a result, the water molecules present in the clay interlayer space were expelled, and the interlayer space of the clay decreased to the maximum extent. The inhibition performance of alkylamines on bentonite clearly increases with the increasing of number of primary amine groups. Therefore, a mixture of alkylamines with multiple primary amine groups is a promising intercalating inhibitor that can be used along with water-based drilling fluids has broad application prospects.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.005
      Issue No: Vol. 136 (2016)
  • Structural changes in smectite due to interaction with a
           biosurfactant-producing bacterium Pseudoxanthomonas kaohsiungensis
    • Authors: Bhabananda Biswas; Argha Chakraborty; Binoy Sarkar; Ravi Naidu
      Pages: 51 - 57
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Bhabananda Biswas, Argha Chakraborty, Binoy Sarkar, Ravi Naidu
      Clays including bentonite hold a great potential in improving the efficacy of organic contaminants degradation by bacteria. However, the mechanisms of interactions involving both biotic (microorganisms) and abiotic (clays) components during bioremediation are largely unknown. Here, we report the interaction of a biosurfactant producing bacterium, Pseudoxanthomonas kaohsiungensis, with bentonite clay. Using instrumental analyses including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma mass spectroscopy (ICP-MS), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) techniques we investigate the microstructural changes of smectite following introduction of the bacterium. The interaction resulted in a spherical clay-bacterial micro-agglomerate formation which deciphered an enhanced growth of the bacterium in a minimal medium supplemented with traces of olive oil. The bacterium brought about a significant dissolution of silicon (Si) preferentially from the tetrahedral silica edges of smectites. The deposition of bacterial biosurfactants and exopolysaccharides (EPS) slightly expanded the smectite interlayers and modified the clay's interaction with water molecules. This study has direct implication in the clay-mediated bioremediation of hydrophobic organic contaminants in the environment.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.008
      Issue No: Vol. 136 (2016)
  • Aggregate size effect on the development of cementitious compounds in a
           lime-treated soil during curing
    • Authors: Yejiao Wang; Myriam Duc; Yu-Jun Cui; Anh Minh Tang; Nadia Benahmed; Wen Jing Sun; Wei Min Ye
      Pages: 58 - 66
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Yejiao Wang, Myriam Duc, Yu-Jun Cui, Anh Minh Tang, Nadia Benahmed, Wen Jing Sun, Wei Min Ye
      This work aims to investigate the aggregate size effect on changes in mineralogical composition and microstructure of lime-treated compacted soils. Three soil powders with different maximum aggregate sizes (D max =5, 1 and 0.4mm) were prepared prior to the treatment with 2% of lime. X-ray diffraction (XRD), environmental scanning electron microscope (Env. SEM) coupled with chemical analysis using energy dispersive X-ray spectrometry (EDX) and mercury intrusion porosimetry (MIP) were used to analyse untreated and treated samples at various curing times. Crystallized C-S-H on tobermorite form was identified in the lime-treated soil prepared with large aggregates after one year curing, and an evident increase in nanopores <0.1μm C-S-H was also observed due to C-S-H creation. By contrast, in the case of smaller aggregates, no obvious C-S-H peaks were observed by XRD technique after the same curing time, even though some evidence of such phases are provided by Env. SEM coupled to EDX analysis. But a large amount of undetectable nanopores <6nm (considering the MIP technical limitation) was supposed to be formed and could be attributed to the creation of nanocrystallized C-S-H or poorly-crystallized C-S-H (that may fill the pores larger than 2μm). Such type of C-S-H phases occurred when lime was coated in thin layer on the large surface associated to lime-treated soil prepared with small aggregates.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.003
      Issue No: Vol. 136 (2016)
  • Synthesis of CdS/MgAl layered double hydroxides for hydrogen production
           from methanol-water decomposition
    • Authors: Sonia Mancipe; Francisco Tzompantzi; Ricardo Gómez
      Pages: 67 - 74
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Sonia Mancipe, Francisco Tzompantzi, Ricardo Gómez
      MgAl layered double hydroxide with molar ratio Mg/Al=3:1, and CdS/MgAl containing 5, 10, 15 and 20wt% of CdS were synthesized by the co-precipitation method. X-Ray diffraction (XRD) of the solids showed characteristics reflections of hydrotalcite type materials in a hexagonal lattice with R-3m rhombohedra symmetry, additionally a wurtzite type hexagonal crystalline structure of CdS which is the most efficient crystalline phase as photocatalysts. Nitrogen adsorption isotherms were obtained and specific surface areas around 30m2/g for all the CdS/MgAl solids were found which are of the same order found on the MgAl LDH. Fourier transform infrared spectroscopy (FTIR) spectra showed an intense band characteristic of ν3 vibrations (antisymmetric stretching) of CO3 2– ions located in the interlamellar region of the LDH and it remains constant in the CdS/MgAl samples. Scanning Electron Microscopy study coupled to a detector for energy dispersive X-ray spectroscopy microanalysis (SEM/EDS) showed that the CdS is well dispersed on the surface of the MgAl. UV–Vis spectroscopy showed that the ban-gap Eg of the samples is around 2.30eV close to that obtained in the CdS reference solid (2.26eV). The photocatalytic activity under irradiation UV light of the compounds in the hydrogen production from the methanol-water decomposition was evaluated showing that the activity of CdS/MgAl photocatalysts after 7h under irradiation was up to 20 times superior (1100H2μmol/CdSg) than the CdS (53H2μmol/CdSg), being the CdS/MgAl 5% the best photocatalyst.
      Graphical abstract image

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.013
      Issue No: Vol. 136 (2016)
  • The mineralogy of the clayey-silty siliceous rocks in the Bazhenov Shale
           Formation (Upper Jurassic) in the west Siberian Basin, Russia: The role of
           diagenesis and possible implications for their exploitation as an
           unconventional hydrocarbon reservoir
    • Authors: M.V. Shaldybin; Y.M. Lopushnyak; I.V. Goncharov; M.J. Wilson; L. Wilson; B.G. Mendis
      Pages: 75 - 89
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): M.V. Shaldybin, Y.M. Lopushnyak, I.V. Goncharov, M.J. Wilson, L. Wilson, B.G. Mendis
      The Bazhenov Shale Formation (BSF) of the west Siberian Basin is considered to be a promising unconventional hydrocarbon reservoir, acting as a source, store and seal of the oil and gas contained therein. It has a high content of organic matter, ranging from 2 to 20% (average 8–12%), and was deposited in a marine environment at an average water depth of 2220 to 2500m where depositional conditions were of an intensely reducing nature. Deposition took place over a period of 8 to 10 million years mainly during Upper Jurassic times. This study reports the mineralogy of 83 core samples representative of the clayey-silty siliceous rocks of the Bazhenov Shale Formation (BSF) taken from six wells in the south-east of the west Siberian Basin. The mineralogy of most samples was found by X-ray diffraction (XRD) to be strikingly similar with most being dominated by quartz, and with albite, mica-like minerals (illite plus mixed-layer illite/smectite (I/S)) and pyrite commonly occurring in subsidiary amounts. Kaolinite and chlorite occur intermittently, usually in no great quantity. Throughout all six wells, plagioclase feldspar (albite) predominates over K-feldspar which is only of sporadic occurrence. The clay (<2μm) fraction of available core samples largely consists of illitic material comprising a combination of true illitic mica and mixed-layer I/S with R3 stacking. Both optical microscopy and scanning electron microscopy (SEM) show the BSF to be composed of a mixture of detrital and authigenic minerals. Thus, quartz occurs as a detrital mineral and as the crystallized product of radiolarian tests subsequent to deposition. The micaceous (muscovitic) material seen in thin section is clearly of terrigenous origin but the fine-grained illitic material is considered to be at least partly diagenetic . With regard to feldspars, although thin sections show some to be detrital, it is considered that albite is also likely to be a diagenetic mineral, as it is in many sandstone reservoirs. In many of the core samples albite is the only feldspar detectable and it is improbable that provenance could yield feldspar detritus consisting only of pure albite over such an extended period of time. Other minerals in the BSF must also be regarded as diagenetic rather than detrital. This is certainly true of the carbonate minerals and pyrite, and the book-like aggregates and euhedral morphology of kaolinite observed by SEM and TEM are also indicative of a diagenetic origin. Finally, the illitic clay mineralogy of the BSF is considered in a general way in the context of their permeability, particularly as it relates to their anisotropic structure and pore water chemistry. It is also suggested that the siliceous nature of the Bazhenov shale makes it a suitable candidate for the creation of enhanced permeability through hydraulic fracturing technology, although matrix permeability may be adversely affected by reactions involving the external basal surfaces of the illitic clays exposed in slit-like pores.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.009
      Issue No: Vol. 136 (2016)
  • Rapid preparation of nano hexagonal-shaped hydrocalumite via one-pot
           mechanochemistry method
    • Authors: Abbas Fahami; Gary W. Beall; Saeid Enayatpour; Fariborz Tavangarian; Mohammad Fahami
      Pages: 90 - 95
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Abbas Fahami, Gary W. Beall, Saeid Enayatpour, Fariborz Tavangarian, Mohammad Fahami
      Hexagonal-shaped hydrocalumite (Ca–Al layered double hydroxides) was successfully synthesized by one-step mechanochemistry method within only 30min. The product was characterized by X-ray diffraction, Fourier Transform Infrared spectroscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, elemental mapping analysis, transmission electron microscopy, X-ray fluorescence, and thermogravimetric analysis. The results showed that the formation of a well-defined hydrocalumite and the microstructural evolution were strongly dependent on the milling time. From XRD profiles, a well-crystallized hydrocalumite with higher peaks intensity was formed after 60min of milling, while the sharpness and intensity of LDH-derived XRD peaks decreased as milling time increased. Microscopic analysis showed that the product had hexagonal layered structure with lateral dimension of 100 to 200nm. In addition, the thermal decomposition of the product is reported in details. This study offers a low-cost approach to synthesis of hydrocalumite owing to simplicity and extremely short processing time.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.014
      Issue No: Vol. 136 (2016)
  • Influence of an ionic liquid on rheological and filtration properties of
           water-based drilling fluids at high temperatures
    • Authors: Zhihua Luo; Jingjing Pei; Longxiang Wang; Peizhi Yu; Zhangxin Chen
      Pages: 96 - 102
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Zhihua Luo, Jingjing Pei, Longxiang Wang, Peizhi Yu, Zhangxin Chen
      Ionic liquids have attracted significant research interest due to their unique thermal stability. In this paper, the influence of a water-soluble ionic liquid on the rheological and filtration properties of water-based drilling fluids at high temperature is investigated. The drilling fluids are evaluated by means of rheological and filtration tests following the American Petroleum Institute (API) standards, submitted to an aging process or at high temperature. The experimental results show that the rheological behavior of water-based drilling fluids is improved and enhanced in the presence of low concentration of ionic liquid (as low as 0.05mass%) at high temperatures (even up to 240°C). Meanwhile, the high-temperature and high-pressure (HTHP) filtration volumes are reduced by as much as 52% compared with that of polymer water-based drilling fluids without ionic liquid. The study of the mechanism demonstrates that the water-soluble ionic liquid have an excellent capacity to improve the rheological and filtration properties of water-based drilling fluids at high temperatures due to the high thermal stability and cation exchange ability of the ILA.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.015
      Issue No: Vol. 136 (2016)
  • A novel strategy for preparation of an effective and stable heterogeneous
           photo-Fenton catalyst for the degradation of dye
    • Authors: Shanshan Chen; Yuhan Wu; Gang Li; Jianning Wu; Guihua Meng; Xuhong Guo; Zhiyong Liu
      Pages: 103 - 111
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Shanshan Chen, Yuhan Wu, Gang Li, Jianning Wu, Guihua Meng, Xuhong Guo, Zhiyong Liu
      A novel strategy was applied in the synthesis of γ-Fe2O3 pillared bentonite (γ-Fe2O3-P-Bent) by intercalating Fe3+ into bentonite in the presence of the surfactant CTAB as an expanding agent and template agent. Then γ-Fe2O3-P-Bent catalyst was used as a heterogeneous catalyst for photo-Fenton degradation of organic contaminants. CTAB can promote the formation of crystalline γ-Fe2O3 in the process of calcination. In addition, the CTAB also significantly increased the surface area of the composites. Only the α-Fe2O3 pillared bentonite (α-Fe2O3-P-Bent) could be obtained under the same conditions without CTAB. The as-obtained composites were well characterized by various techniques to study their morphological, structural and magnetic properties. The specific surface area of the γ-Fe2O3-P-Bent catalyst increased from 29 to 117m2/g compared to bentonite. The saturated magnetization (Ms) values of γ-Fe2O3-P-Bent was 10emu/g. The effects of various reaction parameters such as H2O2 dosage, initial pH value, γ-Fe2O3-P-Bent dosage on the degradation of RhB were studied. Under the best conditions (0.2g/L of catalyst, 10mM of H2O2), the γ-Fe2O3-P-Bent catalyst displayed to possess superior degradation ability to Rhodamine B (RhB) comparing the results with the α-Fe2O3-P-Bent. The catalyst showed efficient for the degradation of other organic dyes as well. After five reaction cycles the catalyst still showed high photocatalytic activity (91%), which showed that the magnetic catalyst possessed very stable, highly reactive, and easy to separate by an external magnetic field. Hence, this facile and high efficiency method may be extended to fabricate other types of magnetic materials.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.016
      Issue No: Vol. 136 (2016)
  • Recent development of layered double hydroxide-derived catalysts
           −Rehydration, reconstitution, and supporting, aiming at commercial
    • Authors: Katsuomi Takehira
      Pages: 112 - 141
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Katsuomi Takehira
      Layered double hydroxide (LDH) has a unique feature, i.e., reconstitution of layered structure from the calcined oxides. The application of LDH as the heterogeneous catalysts by adopting reconstitution phenomenon and supporting on appropriate carrier were reviewed aiming at their commercial uses. After a short explanation on fundamental properties of LDH, such as phase transition by calcination and rehydration of calcined LDH (reconstitution of LDH by “memory effect”), their applications in the catalyst preparations were discussed. By adopting “memory effect”, the surface of LDH-derived mixed oxide was rehydrated or reconstituted as well as decorated with various metals and anions, resulting in an enhanced catalytic activity and selectivity via base sites activation and high dispersion of active metal species. Active OH− species, as Brønsted base, was produced on calcined Mg-Al LDH after the rehydration and exhibited high activity in various reactions. Catalytically active transition metals such as Ni, Fe and Mn were highly dispersed on Mg(Al)O via reconstitution, resulting in the high catalytic activity in dehydrogenation and oxidation reactions. Pt-Sn/Mg(Al)O catalysts prepared by adopting reconstitution phenomenon exhibited an excellent activity in the dehydrogenation of propane to propene. This is owing to the formation of highly dispersed and stable Pt-Sn bimetallic species on the catalyst surface. By supporting LDH on magnetic carriers such as ferrite, the catalyst became magnetically separable and could be utilized recyclably in the fine chemicals synthesis. Paper structured catalyst prepared from LDH by utilizing paper making technology opened new type usage of LDH materials which can be applied in the reforming catalysts for fuel cells. Moreover the reconstitution phenomena donate several beneficial properties to the LDH-derived mixed oxides in their uses as the heterogeneous catalysts. Reconstitution of LDH kinetically accelerated the conversion of anions such as toxic NO3 − and refractory (COO)2− in aqueous solution by entrapping the anions in the interlayer space of rehydrated LDH as observed on Pd-Cu/Mg(Al)O and Cu/Mg(Al)O catalysts, respectively. In the reforming of hydrocarbons for H2 production, self-regenerative activity appeared on trace amount of Pt doped Ni/Mg(Al)O catalyst by reversible oxidation-reduction between Ni0 and Ni2+ on/in Mg(Ni,Al)O periclase assisted by reversible change between periclase and LDH structure of the support. Both Pt-Ni/Mg(Al)O and Pt-Sn/Mg(Al)O catalysts exhibited excellent activities almost closing to the commercial uses.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.012
      Issue No: Vol. 136 (2016)
  • Dendrimers-containing organoclays: Characterisation and interaction with
           methylene blue
    • Authors: Abdellah Beraa; Mohamed Hajjaji; Régis Laurent; Anne-Marie Caminade
      Pages: 142 - 151
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Abdellah Beraa, Mohamed Hajjaji, Régis Laurent, Anne-Marie Caminade
      The structure of organoclays composed of synthesized phosphorus-based dendrimers, which was endowed with peripheral ammonium groups, and stevensite- or montmorillonite-rich clays was examined using X-ray diffraction, high resolution transmission electron microscopy, thermal analysis and solid-state nuclear magnetic resonance. The interactions between methylene blue (MB) and the organoclays or Na+-saturated clay minerals were investigated. The results showed that both dendrimers adsorbed on Na+-saturated clay minerals by cation exchange, and that the organoclays, particularly those of the first generation dendrimers, were mainly composed of intercalated nanocomposites. As a result of the adsorption of the dendrimers, the clay hydrophilicity reduced and the dehydroxylation temperature of the clay minerals increased. Regarding the adsorption of MB on the organoclays, the results pointed out that MB mainly adsorbed as MB+ and MBH2+, and the electronic environments of AlIV of montmorillonite and that of AlVI of stevensite were disturbed. For some organoclays, ordered structures were formed, and the Si4+ substituent (Al3+) left the tetrahedral sheet. The thermodynamic data indicated that MB adsorbed spontaneously (−11.3<∆G° <−0.9kJ/mol) and the uptake of MB by montmorillonite-based organoclays was believed to occur by chemisorption. In contrast, for stevensite-based organoclays MB adsorption seemed to be accomplished by physisorption.

      PubDate: 2016-11-25T07:49:43Z
      DOI: 10.1016/j.clay.2016.11.017
      Issue No: Vol. 136 (2016)
  • Novel kaolinite based coolant for hyperthermal pyrotechnic aerosol cooling
    • Authors: Xiaotian Zhang; Mohd Halim Shah Ismail; Fakhrul-Razi B. Ahmadun; Norhafizah Bt. Hj. Abdullah; Choi Hee
      Pages: 152 - 157
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Xiaotian Zhang, Mohd Halim Shah Ismail, Fakhrul-Razi B. Ahmadun, Norhafizah Bt. Hj. Abdullah, Choi Hee
      Novel spherical pyrotechnic aerosol cooling granulates which are made of 42.8% kaolinite powder, 38.8% water, 8.1% epoxy A&B glue and 10.2% ethyl cellulose are successfully synthesized and can cool down the temperature of hot pyrotechnic aerosol from 1400 to 400°C below with only a 1:1 mass ratio of coolant to the aerosol forming agent. The cooling system is a packing bed randomly stacked with 5mm diameter cooling granulates. The kaolinite based cooling granulate has proper yield stress to provide the cooling bed a constant porosity in order to avoid any tunneling effect and granulate structural failure during hot aerosol cooling. Moreover, the synthesis process of current novel kaolinite based granulate coolant is simple and economic. Compared to other coolants like irregular granite gravels or ceramic intalox used for pyrotechnic aerosol cooling, the cooling performance of spherical kaolinite based cooling granulates is superior.

      PubDate: 2016-12-01T00:30:51Z
      DOI: 10.1016/j.clay.2016.11.019
      Issue No: Vol. 136 (2016)
  • Catalytic activity of mineral montmorillonite on the reaction of phenol
           with formaldehyde
    • Authors: Miroslav Huskić; Ema Žagar
      Pages: 158 - 163
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Miroslav Huskić, Ema Žagar
      Phenolic resins of novolac type were synthesized in the presence of the mineral montmorillonite in its pristine (Na-Mt) or protonated form (H-Mt), with and without oxalic acid (OA) as a catalyst. The H-Mt acts as a strong catalyst regardless of the presence of OA. Contrary, when Na-Mt was added to the OA-catalysed reaction mixture the reaction yield decreased, however, a catalytic effect was observed in the absence of the OA catalyst. The structure of novolac resins is influenced by the addition of both, the Na-Mt and the H-Mt. While the H-Mt influences only a ratio between the o-o, o-p and p-p ethylene bridges, the Na-Mt, in the absence of OA, favours the formation of methylene ether bridges. The molar mass averages of novolac resins synthesized in OA catalysed reactions were always higher than in the absence of OA. Differences in the chemical structure influence the resins' glass transition temperature, which can be even below 0°C.
      Graphical abstract image

      PubDate: 2016-12-01T00:30:51Z
      DOI: 10.1016/j.clay.2016.11.020
      Issue No: Vol. 136 (2016)
  • Physicochemical approach for analyzing equilibrium volume of clay
           sediments in salt solutions
    • Authors: Tadikonda Venkata Bharat; Dhanesh Sing Das
      Pages: 164 - 175
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Tadikonda Venkata Bharat, Dhanesh Sing Das
      Equilibrium sediment volume (ESV) is used as an important parameter for understanding the expansive nature of the bentonites and natural clay soils, for assessing a given bentonite for engineering applications, and for the determination of the type of dominant clay mineral present in a given soil. The ESV is often estimated using different salt solutions to understand the compatibility of given clay soil for long-term engineering application such as landfills. A theoretical approach based on physicochemical behavior of clays was proposed in this paper for the estimation of equilibrium sediment volume of bentonites in the presence of salt solutions. A simple analytical expression relating equilibrium sediment volume with different influencing physicochemical parameters such as clay surface and pore-fluid parameters was presented using the diffuse double layer theory. A quantitative estimation of ESV by the proposed theory was validated on the measured data. A very good agreement between the theoretical and measured data was observed for the commercial bentonite. The theory was in good agreement with the measurements in the concentration range of 0.01M≤n<1M for Kutch bentonite while the concentration range was 0.001M≤n<1M for Barmer bentonite in NaCl solutions. The influence of different exchangeable cations and the presence of non-clay content on the prediction were analyzed with a great detail using theory and by comparing the ESV data of studied bentonites with the homoionic sodium clay. The parallel plate assumption made in the theory overestimated the ESV data in CaCl2 solution. The proposed analytical model is very useful for understanding the influencing parameters on the bentonite behavior.
      Graphical abstract image

      PubDate: 2016-12-01T00:30:51Z
      DOI: 10.1016/j.clay.2016.11.021
      Issue No: Vol. 136 (2016)
  • Mineralogical characterization of Neogene clay areas from the Jijel basin
           for ceramic purposes (NE Algeria -Africa)
    • Authors: Baghdad Abdelmalek; Bouazi Rekia; Bouftouha Youcef; Bouabsa Lakhdar; Fagel Nathalie
      Pages: 176 - 183
      Abstract: Publication date: February 2017
      Source:Applied Clay Science, Volume 136
      Author(s): Baghdad Abdelmalek, Bouazi Rekia, Bouftouha Youcef, Bouabsa Lakhdar, Fagel Nathalie
      Clayey marl from four localities in the Neogene basin of Jijel (NE Algeria) were studied by mineralogical and physico-chemical characterization in order to evaluate their potential suitability as raw materials in ceramic applications. X-ray diffraction (XRD) and Fourier Transform-Infrared (FT-IR) spectrometry are used to establish the mineralogical composition. Chemical and physical properties were carried out by XRF and particle size distribution, consistency limits, calcimetry of Bernard and density of solid particles, respectively. Quartz, clay and calcite were present as dominant mineral phases associated with feldspars, plagioclase and dolomite. The clay minerals prevail in all samples, with kaolinite and illite being the dominant phase and interstratified 10–14Å and chlorite, comprising the rest of the clay components. The chemical compositions indicated that SiO2 (42–54%), Al2O3 (12–19%) and CaO (2–17%) are major elements while Fe2O3 is less abundant (4–8%). The classification of the clays using appropriate ternary diagrams suggests their possible use in the production of red products like tiles and masonry bricks.

      PubDate: 2016-12-01T00:30:51Z
      DOI: 10.1016/j.clay.2016.11.025
      Issue No: Vol. 136 (2016)
  • Session on Asian Clay Minerals Group Research in Progress: From natural to
           industrial clays
    • Authors: Jinwook Kim; Jin-Ho Choy; Jae-Min Oh; Hongping He; Peng Yuan; Hyen Goo Cho
      First page: 1
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): Jinwook Kim, Jin-Ho Choy, Jae-Min Oh, Hongping He, Peng Yuan, Hyen Goo Cho

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.08.014
      Issue No: Vol. 134 (2016)
  • Cyclic organic carbonate modification of sodium bentonite for enhanced
           containment of hyper saline leachates
    • Authors: A. Fehervari; W.P. Gates; T.W. Turney; A.F. Patti; A. Bouazza
      Pages: 2 - 12
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): A. Fehervari, W.P. Gates, T.W. Turney, A.F. Patti, A. Bouazza
      Two cyclic organic carbonates (COC), propylene carbonate (PC) and glycerol carbonate (GC), were investigated as saline-resistant modifying agents of Na+-montmorillonite using X-ray diffraction (XRD) and Fourier transform infrared (FTIR). PC has been studied previously and has been used as an effective amendment material of Na+-bentonite for saline applications. In this research GC is proposed as a more effective modifying agent for containing hyper saline leachates. Na+-montmorillonite was reacted with up to 1N sodium chloride (NaCl) and calcium chloride (CaCl2) salt solutions to assess changes in the interlayer spacing (i.e., d-value of the 001 reflection in XRD traces) due to osmotic desiccation, as well as to investigate the mechanism and strength of bonding between GC/PC and Na+-montmorillonite by FTIR. GC/Na+-montmorillonite was strongly resistant against strongly saline sodic salt solution compared to PC/Na+-montmorillonite. CaCl2 solution had a more detrimental effect on COC modified Na+-montmorillonite, however, GC/Na+-montmorillonite appeared to retain more intercalated COC than PC/Na+-montmorillonite when leached by strong calcic salt solutions.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.09.007
      Issue No: Vol. 134 (2016)
  • Biogeochemical dissolution of nontronite by Shewanella oneidensis MR-1:
           Evidence of biotic illite formation
    • Authors: Tae-hee Koo; Gunjeong Lee; Jin-wook Kim
      Pages: 13 - 18
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): Tae-hee Koo, Gunjeong Lee, Jin-wook Kim
      Microbial Fe-reduction in smectite structure plays a significant role in illitization accompanying with the structural/chemical modification of smectite, closely linked to the physico-chemical properties of clays, Fe-liberation, water chemistry, elemental cycles, and fault behavior. Biotic dissolution of smectite is a major process that promotes illitization, however direct evidence of illite formation is not clearly understood. In the present study, a combination of spectroscopic, microscopic, and chemical analyses revealed evidence of illitization in bio-reduced smectite, with elemental composition measured on a nanoscale as incubation time increased. Fe-reducing bacteria (FeRB), Shewanella oneidensis MR-1 was inoculated in M1 medium with nontronite (NAu-1) less than 0.2μm as an electron acceptor and Na-lactate as a sole electron donor at 30°C in the anaerobic chamber for up to 120days. The alkalinity was maintained at pH8.0 in the whole experiment to enhance illite formation. The extent of Fe(III) reduction measured by 1,10-phenanthroline assay reached up to 10.6% in the experiment while less than ~1% of reduction was measured in no-bacteria control. In biotic and abiotic control, increases of elemental concentrations (Si, Al, and Fe) in the supernatant indicated the dissolution of nontronite. The progress of bio-reduced nontronite reaction can be explained as follows: altered nontronite (AN) with a scouring surface texture→K-nontronite (KN) with frayed edges→euhedral lath shaped illite. A progressive morphology change in bio-reduced nontronite corresponded to an increase in Al/Si and K/(K+2Ca) that ranged between 0.13 and 0.28 and 0.16 to 1.0, suggesting the biotic reductive dissolution of nontronite and neoformation of illite. The precipitation of biotic amorphous silica supported the reductive dissolution of nontronite. In contrast, there was no clear evidence of mineral precipitation in no-bacteria control. Following treatment with Li and ethylene glycol for the long-term incubation (70 and 120days), the X-ray diffraction (XRD) profiles confirmed illitization by displaying a 10-Å peak shoulder at around 8.9° 2θ in the bio-reduced nontronite. Indeed, a direct microscopic observation of distinct illite packets of 16nm in thickness with d001 =1.0nm in the wavy nontronite matrix with various spacings (d001 =1.2–1.3nm) strongly suggested biotic illite formation.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.03.030
      Issue No: Vol. 134 (2016)
  • Nano-biohybrids of engineered nanoclays and natural extract for
           antibacterial agents
    • Authors: Hyoung-Jun Kim; Tae-Hyun Kim; Hyoung-Mi Kim; In-Kee Hong; Eun-Ji Kim; Ae-Jin Choi; Hyun-Jin Choi; Jae-Min Oh
      Pages: 19 - 25
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): Hyoung-Jun Kim, Tae-Hyun Kim, Hyoung-Mi Kim, In-Kee Hong, Eun-Ji Kim, Ae-Jin Choi, Hyun-Jin Choi, Jae-Min Oh
      We have prepared nano-biohybrids between engineered nanoclays and antibacterial natural extract. Agrimonia pilosa Ledeb (AP) was treated with either hot water or ethanol to obtain two kinds of extract, and we found that water extract was more efficient in bacterial inhibition. Pore volume and specific surface area of three clays, such as illite, scoria and hydrotalcite, were engineered with acid or heat, before hybridization. Nano-biohybridization was carried out with engineered nanoclays powder and extract solution. According to thermogravimetry and dry weight method, it was determined that extract content in hybrid were between 11.6 and 39.5%. X-ray diffraction patterns showed that the crystal structure of engineered nanoclay was preserved after hybridization. Scanning electron microscopy, extract content analyses and zeta potential measurement suggested that the surface of nanoclays were evenly and thoroughly covered with extract moiety with a few molecular layers. Differential thermal analyses on hybrid indicated broad and lowered combustion temperature of extract components in hybrids compared with extract only, suggesting possible molecular rearrangement of extract moiety on nanoclay surface. We then evaluated bacterial colony forming inhibition of extract and nano-biohybrids of which result indicated higher antibacterial efficacy of hybrids than extract itself.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.05.003
      Issue No: Vol. 134 (2016)
  • Removal mechanism of arsenate by bimetallic and trimetallic hydrocalumites
           depending on arsenate concentration
    • Authors: Yu Takaki; Xinhong Qiu; Tsuyoshi Hirajima; Keiko Sasaki
      Pages: 26 - 33
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): Yu Takaki, Xinhong Qiu, Tsuyoshi Hirajima, Keiko Sasaki
      We investigated the influence of initial arsenate concentration (C 0) in the 5th order of magnitude on removal of arsenate by hydrocalumite (bimetallic layered double hydroxide, LDH) and Mg-doped hydrocalumite (trimetallic LDH) from aqueous solution. These hydrocalumites were prepared by the microwave-assisted hydrothermal treatment. There is a trend that the larger adsorption density of arsenate (Q e) values is observed with bimetallic LDH under low C 0 values and with trimetallic LDH under high C 0 values. The transitional C 0 values ranged at 2.10–2.96mM. Comprehensively understanding characterization results for the solid residues after adsorption of arsenate by X-ray diffraction, 27Al-nuclear magnetic resonance, and scanning electron microscopy–energy dispersive X-ray, the mechanism to remove arsenate was dependent on arsenate concentrations. At low arsenate concentration, partial intercalation and dissolution–reprecipitation (DR) happened together. With increasing C 0, full intercalation and DR happened to bring out one phase of arsenate-bearing hydrocalumite. Under the very high C 0, DR mechanism happened at the edge sites of LDH sheets, leading that the newly formed massive precipitates block the further intercalation with nitrate. As a result, two phases of LDH were observed. The greater Q e with bimetallic LDH in low concentration comes from high crystallinity to enhance partial ion-exchange, and greater Q e with trimetallic LDH in high concentration is derived from more fragile properties to enhance DR mechanism.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.05.010
      Issue No: Vol. 134 (2016)
  • Smectite, illite, and early diagenesis in South Pacific Gyre subseafloor
    • Authors: Kiho Yang; Jin-wook Kim; Toshihiro Kogure; Hailiang Dong; Hionsuck Baik; Bryce Hoppie; Robert Harris
      Pages: 34 - 43
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): Kiho Yang, Jin-wook Kim, Toshihiro Kogure, Hailiang Dong, Hionsuck Baik, Bryce Hoppie, Robert Harris
      Subseafloor sediment and basalt rock samples at seven sites in the South Pacific Gyre (SPG) were recovered by Integrated Ocean Drilling Program Expedition 329 (2010.10.8–2010.12.13). Microscopic and spectroscopic measurements on the structural Fe-redox states and the elemental composition of smectite, and polytypes of illite in the sediment at two sites (U1365 and U1369) were performed to understand the origin/formation mechanism of clay minerals in the oligotrophic open ocean. The dominant phases of clay minerals found in the present study were smectite and illite polytypes. Suggestive of non-uniform early diagenetic processes in the expansive SPG seafloor, higher ordering of illite polytypes (1M, 2M 1 , and 3T) were identified at site U1369 while disordered 1M d illite were found at U1365. Smectites of hydrothermal origin (Al-rich beidellite, and saponite) were observed at U1369. Fe-rich montmorillonite minerals that are likely associated with the terrigenous input, were dominant at U1365. Nontronite (Fe-rich smectite) was detected at both sites. Red-brown to yellow-brown semiopaque oxide minerals (RSO) were widely distributed with Fe-rich smectite near the basaltic crust at U1365. Lower observed heat flow at U1365 relative to U1369 provides a possible explanation for the observed variability in clay mineral speciation between these two sites. The presence of K-nontronite at the basalt/sediment interface at both sites indicates an oxidative basalt alteration; however variations in the oxidation states of structural Fe in nontronite measured by EELS indicate that reductive environment persists locally at the basalt/sediment interface.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.03.041
      Issue No: Vol. 134 (2016)
  • Synthesis of hydrotalcite type layered double hydroxide with various Mg/Al
           ratio and surface charge under controlled reaction condition
    • Authors: Ji-Yeong Lee; Gyeong-Hyeon Gwak; Hyoung-Mi Kim; Tae-il Kim; Gyeong Jin Lee; Jae-Min Oh
      Pages: 44 - 49
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): Ji-Yeong Lee, Gyeong-Hyeon Gwak, Hyoung-Mi Kim, Tae-il Kim, Gyeong Jin Lee, Jae-Min Oh
      In order to control Mg/Al ratio in hydrotalcite type layered double hydroxide (LDH), LDH was prepared through coprecipitation under varied synthetic parameters such as initial Mg/Al ratio (from 1 to 20) in metal solution and coprecipitation pH (9.5, 10, 10.5 and 11). Phase evolution of hydrotalcite or impurities was examined with powder X-ray diffraction pattern and the Mg/Al ratio in final product was evaluated with inductively coupled plasma-atomic emission spectroscopy. It was found that the nominal Mg/Al ratio did not correspond to the final values, showing narrow correlation range between 1 and 3 at relatively low pH~9.5. By raising coprecipitation pH upto 11, Mg/Al ratio successfully increased in final LDH product upto 15.4. Under controlled initial Mg/Al ratio and coprecipitation pH, various LDHs with Mg/Al ratio between 1 and 16, which corresponded to layer charge density between 0.5 and 6(+)/100Å2, were obtained. The charge density and surface charge of LDHs exhibited linear correlation, showing zeta potential value 16–40mV at neutral pH.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.03.029
      Issue No: Vol. 134 (2016)
  • Smart montmorillonite-polypyrrole scaffolds for electro-responsive drug
    • Authors: Ren Wang; Yonggang Peng; Min Zhou; Dan Shou
      Pages: 50 - 54
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): Ren Wang, Yonggang Peng, Min Zhou, Dan Shou
      Hybrids of montmorillonite (Mt) and polypyrrole (PPy) were prepared by in situ electropolymerization of pyrrole monomer in the dispersion of Mt in the presence of drug molecules (aspirin), and aspirin anions were incorporated into the Mt-PPy hybrids as dopants. The resulting drug loaded Mt-PPy was characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), electrochemical impedance spectroscopy (EIS), and X-ray powder diffractometer (XRD). The Mt-PPy hybrids combined the advantages of Mt (relatively large specific surface area) and electro-responsive feature of PPy, which was applied as an electrically tunable drug release platform. Compared with PPy, the electro-stimulated drug release behaviors were significantly enhanced at the Mt-PPy hybrids, indicating that the proposed electro-responsive hybrids might be a promising candidate for smart and intelligent drug release.

      PubDate: 2016-11-12T11:27:07Z
      DOI: 10.1016/j.clay.2016.05.004
      Issue No: Vol. 134 (2016)
  • Paleo-environmental change during the late Holocene in the southeastern
           Yellow Sea, Korea
    • Authors: Kyeong Yoon Kwak; Hunsoo Choi; Hyen Goo Cho
      Pages: 55 - 61
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 1
      Author(s): Kyeong Yoon Kwak, Hunsoo Choi, Hyen Goo Cho
      Origin of fine-grained terrigenous sediments and integrative interpretation of their detailed variations in the southeastern Yellow Sea (YS) since the Last Glacial Maximum (LGM) have not been well understood. We investigated the provenance and paleo-environmental changes of the southeastern YS by examining clay mineral changes from borehole HMB-102 and HMB-103. Down-core variations in these clay mineral compositions suggest a distinct change in the provenance of fine-grained sediments of the Heuksan Mud Belt (HMB). Before 13.32ka, sediments were mostly derived from the Korean rivers, from the paleo-Huanghe during between 13.32 to 11.08ka, and from the Korean rivers with minor contributions from the paleo-Huanghe during 11.08 to 6.77ka. After 6.77ka, when the sea level was high and the shoreline was near the Korean Peninsula, materials may come from the Korean rivers. The provenance change after LGM occurred due to an increase in water depth caused by climate change and evolution of Kuroshio Current (KC).

      PubDate: 2016-11-12T11:27:07Z
      DOI: 10.1016/j.clay.2016.05.007
      Issue No: Vol. 134 (2016)
  • Clay and fine particle-based materials for environmental technologies and
           clean up
    • Authors: Binoy Sarkar; Anke Neumann; Ravi Naidu
      Pages: 69 - 70
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 2
      Author(s): Binoy Sarkar, Anke Neumann, Ravi Naidu

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.10.026
      Issue No: Vol. 134 (2016)
  • Kinetics of uranyl ions sorption on heterogeneous smectite structure at
           pH4 and 6 using a continuous stirred flow-through reactor
    • Authors: Vanessa Guimarães; Enrique Rodríguez-Castellón; Manuel Algarra; Fernando Rocha; Iuliu Bobos
      Pages: 71 - 82
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 2
      Author(s): Vanessa Guimarães, Enrique Rodríguez-Castellón, Manuel Algarra, Fernando Rocha, Iuliu Bobos
      The <2μm clay fractions of three smectite samples (BA1, PS2 and PS3) were submitted to UO2 2+ sorption experiments at pH4 (1×10−4) and pH6 (2.0×10−1) in a continuous stirred flow-through reactor. The aim was to evaluate the influence of heterogeneous structure of smectite during the adsorption and desorption processes, where the breakthrough curves (BTCs) were used to model the mass balance. Kinetic models were applied to describe the adsorption – desorption kinetics for a liquid-solid system. Sample PS2 (K-Illite/beidellite/Na,Ca-montmorillonite) adsorbed at pH4 more 34% and 138% of UO2 2+ than samples BA1 (beidellite/Ca,Na-montmorillonite) and PS3 (K-illite/Na,Ca-montmorillonite) where the dominant mechanism was the ion-exchange (outer-sphere complexation). The UO2 2+ amount adsorbed at pH6 decreased significantly, indicating changes in the sorption mechanism. The desorption experiments at pH4 suggested a complete reversibility of the UO2 2+ previously adsorbed, whereas lower reversibility of the UO2 2+ previously adsorbed and a stronger complexation occurred at pH6. The kinetics was highly influenced by the structural properties of heterogeneous smectite and the surface complexation mechanism involved. Samples submitted to sorption experiments at pH4 and 6 were analysed by X-ray photoelectron spectrometry (XPS). Two binding energies were identified at 380.8±0.3eV and 382.4±0.3eV, before and after desorption processes at pH4. The proportion of the higher binding energy component decreased after desorption process, suggesting that the UO2 2+ weakly adsorbed was previously desorbed. The results obtained at pH6 show two different binding energies at 380.3±0.3eV and 381.8±0.3eV, whose proportions remained unchanged before and after desorption process, indicating the higher retention of UO2 2+ on smectite.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.03.028
      Issue No: Vol. 134 (2016)
  • Microelectrophoresis and inverse gas chromatography as tools to study the
           surface interactions between a fluorinated fungicide and raw or
           organically modified Patagonian montmorillonite
    • Authors: F.M. Flores; M. Gamba; R.M. Torres Sánchez; E. Brendlé; J. Brendlé
      Pages: 83 - 88
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 2
      Author(s): F.M. Flores, M. Gamba, R.M. Torres Sánchez, E. Brendlé, J. Brendlé
      The importance of fungicides uses to maintain healthy crops and reliable, high-quality yields poses environmental issues due to the water and soil contaminations. The montmorillonite is known as efficient adsorbent for many pesticides, while the organo modification enabled to use them in wider range of applications. In this study, the fungicide fludioxonil (FDX) was adsorbed on raw and organo-modified Patagonian montmorillonite. The effects of the organo treatment as well as the FDX adsorption on the surface properties were investigated by X-ray diffraction, microelectrophoresis and inverse gas chromatography. The importance of the organo treatment was revealed both for the changes in the surface properties (dispersive component of the surface energy, nanoroughness and surface acidity as well as zeta-potential) and for the adsorption of FDX as it enabled increase two times respect to the pristine montmorillonite.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.02.034
      Issue No: Vol. 134 (2016)
  • Characterization of bentonite modified with humic acid for the removal of
           Cu (II) and 2,4-dichlorophenol from aqueous solution
    • Authors: Xiaoying Jin; Min Zheng; Binoy Sarkar; Ravi Naidu; Zuliang Chen
      Pages: 89 - 94
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 2
      Author(s): Xiaoying Jin, Min Zheng, Binoy Sarkar, Ravi Naidu, Zuliang Chen
      This study examines the modification of bentonite with humic acid (HAB) as a novel sorbent for simultaneous removal of Cu(II) and 2,4-dichlorophenol (2,4-DCP) from aqueous solution. Batch experiments were conducted employing either single sorption or simultaneous sorption of Cu(II) and 2,4-DCP. Results indicated that the sorption of either Cu(II) or 2,4-DCP onto HAB was little influenced by the presence of the other contaminant. The amount of sorption was 22.40mgg−1 and 14.23mgg−1 for Cu(II) and 2,4-DCP, respectively at 30°C. Scanning electron microscopy (SEM) indicated that HA was immobilized on the surface of bentonite. Energy dispersive spectroscopic (EDS) analysis indicated that Cu(II) was sorbed onto HAB. X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of bentonite did not change after being modified with HA. Fourier-transform infrared (FTIR) spectra confirmed that new bonds and band intensity emerged after the sorption of Cu(II) and 2,4-DCP onto the HAB. These suggest that simultaneous sorption of 2,4-DCP and Cu(II) onto HAB could occur through: firstly, a mechanism that partitions between 2,4-DCP and HA; and secondly, the ion-exchange mechanism between Cu(II) and bentonite.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.09.036
      Issue No: Vol. 134 (2016)
  • Structural, electrokinetic and surface properties of activated
           palygorskite for environmental application
    • Authors: Ruhaida Rusmin; Binoy Sarkar; Bhabananda Biswas; Jock Churchman; Yanju Liu; Ravi Naidu
      Pages: 95 - 102
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 2
      Author(s): Ruhaida Rusmin, Binoy Sarkar, Bhabananda Biswas, Jock Churchman, Yanju Liu, Ravi Naidu
      Unlike smectite, the surface characteristics of palygorskite remain underexplored for its potential application in environmental remediation. In this study, palygorskite from Western Australia was activated through thermal (300°C for 4h), acid (4M HCl for 2h at 70°C) and acid-thermal (acid treatment followed by heating at 300°C for 4h) treatments, and the structural and physico-chemical characteristics were examined against the raw clay mineral. The influence of activation was systematically investigated using X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, N2 adsorption-desorption measurements and solid state 27Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy. The XRD patterns indicated preservation of the crystalline structure of palygorskite following all the treatments. These findings were supported by the Al (IV) and Al (VI) coordination peaks (chemical shift ~55 and 2.9ppm, respectively) which were unaltered in the 27Al MAS NMR spectra of the samples. The acid-thermal activated palygorskite exhibited the highest specific surface area (152.7m2 g−1) and pore volume (0.2137cm3 g−1) which respectively were 3-fold and 69% greater than the raw palygorskite. The potentiometric titration analyses highlighted the possible role of Al derivatives towards development of the surface charge of the activated palygorskites. Electrokinetic studies described the stability of the activated products (zeta potential values ranging from -5mV to -32mV) at different electrolyte (NaNO3) concentrations. Combined acid-thermal activated palygorskite displayed a stronger specific adsorption of multivalent cations, and held a direct relevance to environmental remediation. Findings of this study will assist in the development of palygorskite-based adsorbents for heavy metal contaminants remediation.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.07.012
      Issue No: Vol. 134 (2016)
  • Adsorption characteristics of arsenate on colloidal nanosheets of layered
           double hydroxide
    • Authors: Paulmanickam Koilraj; Yu Takaki; Keiko Sasaki
      Pages: 110 - 119
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 2
      Author(s): Paulmanickam Koilraj, Yu Takaki, Keiko Sasaki
      Nanomaterials have gained much interest in water remediation and pollution control in recent years. However, the toxicity associated with nanoparticles remaining in solution after remediation has high impact on the environment. The present study examined the synthesis and characterization of colloidal Mg2Al-NO3 layered double hydroxide (Mg2Al-UD-LDH) nanosheets and their application as adsorbent toward arsenate immobilization. Colloidal LDH nanosheets featured the absence of nanoparticles release in the environment differently from other nanomaterials. The adsorption studies conducted in batch method, revealed that colloidal Mg2Al-UD-LDH nanosheets (obtained by ultrasonic treatment of Mg2Al-NO3-LDH suspension) achieved a higher arsenate adsorption density of 1.21mmol/g than parent Mg2Al-NO3-LDH (1.16mmol/g) at a solid-to-solution dosage of 0.78g LDH/L. The adsorption mechanism of arsenate onto colloidal Mg2Al-UD-LDH nanosheets proceeded through restacking of the nanosheets, besides ion-exchange onto Mg2Al-NO3-LDH and surface adsorption onto Mg2Al-CO3-LDH. Kinetics of arsenate adsorption onto colloidal Mg2Al-UD-LDH nanosheets was rapid, reaching equilibrium within 5min, whereas equilibrium was reached within 120min in the presence of Mg2Al-NO3-LDH. The colloidal LDH nanosheets stacking effect was restricted at higher LDH/As ratios owing to electrostatic repulsion among the nanosheets, as determined by zeta potential measurements. Semi-pilot scale static model systems for arsenate adsorption were examined to further investigate the adsorption performance of colloidal Mg2Al-UD-LDH nanosheets in natural water systems such as river, pond, or lake. Arsenate adsorption was rapid onto colloidal Mg2Al-UD-LDH nanosheets owing to their high dispersibility; specifically, 100% adsorption efficiency was achieved within 5min. Thus, the high adsorption capacity, dispersibility, and fast kinetics of arsenate removal onto colloidal Mg2Al-UD-LDH nanosheets promising for use as an efficient adsorbent for water remediation.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.06.002
      Issue No: Vol. 134 (2016)
  • Layered double hydroxides decorated with Au-Pd nanoparticles to
           photodegradate Orange II from water
    • Authors: Liji Sobhana; Mohamed Sarakha; Vanessa Prevot; Pedro Fardim
      Pages: 120 - 127
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 2
      Author(s): Liji Sobhana, Mohamed Sarakha, Vanessa Prevot, Pedro Fardim
      MgZnAl-Cl layered double hydroxides were prepared by co-precipitation method and further used as support to immobilize gold-palladium (Au-Pd) bimetallic nanoparticles by colloidal sol immobilization method. These materials were characterized by XRD, FT-IR, N2 adsorption desorption, TGA to verify the structure and stability of the heterostructure. The pristine LDH and Au-Pd@LDH were investigated for an environmental purpose, where photocatalytic degradation of orange II (OII) dye was studied as model reaction. The performance of support and catalyst were determined by evaluating both degradation and adsorption phenomenon. Influence of parameters such as catalyst loading and Orange II concentration were evaluated. The current study holds importance in water treatment and similar environmental protection applications.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.06.019
      Issue No: Vol. 134 (2016)
  • Clay mineral indices in palaeo-geothermal and hydrothermal studies
    • Authors: Rafael Ferreiro Mählmann; Hans Albert Gilg; Stephen Hillier; Emilio Galán
      Pages: 161 - 163
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 3
      Author(s): Rafael Ferreiro Mählmann, Hans Albert Gilg, Stephen Hillier, Emilio Galán

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.10.044
      Issue No: Vol. 134 (2016)
  • Correlating illite (Kübler) and chlorite (Árkai) “crystallinity”
           indices with metamorphic mineral zones of the South Island, New Zealand
    • Authors: Laurence N. Warr; Simon C. Cox
      Pages: 164 - 174
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 3
      Author(s): Laurence N. Warr, Simon C. Cox
      Measuring clay mineral “crystallinity” by the illite “Kübler” or chlorite “Árkai” index has long been used to determine the metamorphic grade of pelitic metasedimentary rocks by recognition of the anchizone: a transitional state of regional metamorphism lying between diagenetic and low-grade metamorphic conditions. Originally defined by B. Kübler on the basis of clay mineral paragenesis, the application of the anchizone as a metamorphic tool has remained ambiguous partly due to inconsistencies in the standardization of the method and partly due to the lack of reliable correlations with well accepted metamorphic zones assemblages. In this study, 54 pelitic samples were analyzed from localities of defined mineral facies from the well-studied rocks of the South Island of New Zealand. Standardized Kübler and Árkai indices are presented for this sample suite using the widely applied standardized Crystallinity Index Scale (CIS) of measurement, and employing the new Frey-Kübler equivalent upper and lower boundary limits of the anchizone at 0.32 and 0.52°2θ. The results presented indicate that 76–78% of both Kübler index and Árkai index values correspond with the expected mineral facies when the epizone is taken to correspond to both the greenschist (chlorite-zone) and pumpellyite-actinolite facies, the anchizone to the prehnite-pumpellyite facies and the diagenetic zone to the zeolite facies. This good correspondence between Kübler and Árkai index values and metamorphic mineral zones confirms that clay “crystallinity” indices provide a useful method for mapping regional grades of low temperature metamorphism and the general state of cleavage development. Its effectiveness is, however, dependent on appropriate standardization to an internationally recognized scale of clay mineral “crystallinity” measurement, and implementation of true Kübler-equivalent anchizone boundary limits. The consistent variations between illite and chlorite “crystallinities” observed for the studied pelites of southern New Zealand, as defined on Kübler - Árkai index correlation plots, is suggested to reflect variations in the activities of K+, Fe2+ and Mg2+ in the metamorphic pore fluid.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.06.024
      Issue No: Vol. 134 (2016)
  • Reliability of very low-grade metamorphic methods to decipher basin
           evolution: Case study from the Markstein basin (Southern Vosges, NE
    • Authors: Sébastien Potel; Tatiana Maison; Marine Maillet; Anta-Clarisse Sarr; Michael Patrick Doublier; Ghislain Trullenque; Rafael Ferreiro Mählmann
      Pages: 175 - 185
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 3
      Author(s): Sébastien Potel, Tatiana Maison, Marine Maillet, Anta-Clarisse Sarr, Michael Patrick Doublier, Ghislain Trullenque, Rafael Ferreiro Mählmann
      Low- and very low-grade metamorphic studies investigating the alteration and reaction progress of clay minerals are powerful tools to decipher the thermal evolution of sedimentary and inverted meta-sedimentary basins. Sheet silicates such as illite and chlorite are very common in sedimentary basin sequences. They can be used to determine the grade of diagenesis and low-temperature metamorphism as measured through the XRD: illite Kübler-Index (KI; illite “crystallinity” in older literature) and the chlorite Árkai-Index (ÁI; chlorite “crystallinity” in older literature), respectively. Although the ÁI method is considered to be slightly less sensitive than the KI method, a reliable correlation between both methods is often observed in metamorphic domains with a uniform heat-flow history and minor tectono-structural complexity. Complementary to these methods, the K-white mica b cell dimension provides a robust estimate of pressure facies reached in very low- to low-grade temperature domains. Here, we present a case-study from the Markstein basin located in the Southern Vosges. The lithostratigraphic units in the basin are characterized by deep marine flysch sequences of Upper Devonian to Upper Visean age and volcano-clastic sediments, respectively. The Markstein basin is surrounded by granitoids with intrusion ages between 340 and 326Ma. A previous study showed orogenic deformation characterized by regional folding, and a contact metamorphism found in an outer halo of the granitoids up to 1500m away from the contact (delineated by the occurrence of biotite). Here we present a multi-disciplinary study combining mineral assemblages, illite and chlorite “crystallinity indices”, and K-white mica b cell dimension. Our approach allows to (i) map in (great) detail the areal extent of both regional/burial metamorphic and contact metamorphic domains; (ii) reveal the metamorphic zonation within both domains; and (iii) better constrain regional/burial and contact metamorphic history. The contact metamorphic domain is characterized by the occurrence of biotite and/or actinolite and low K-white mica b cell dimensions, whereas the zone of incipient orogenic metamorphism yields KI and ÁI values of the high-grade diagenesis and anchizone with intermediate K-white b cell dimensions.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.10.003
      Issue No: Vol. 134 (2016)
  • Clay mineral diagenesis in Cretaceous clastic reservoirs from West African
           passive margins (the South Gabon Basin) and its impact on regional geology
           and basin evolution history
    • Authors: Giovanni Zanoni; Branimir Šegvić; Andrea Moscariello
      Pages: 186 - 209
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 3
      Author(s): Giovanni Zanoni, Branimir Šegvić, Andrea Moscariello
      The Gabon coastal region located along the western African margin hosts several sedimentary basins that developed prior, during and after the opening of the South Atlantic Ocean. A range of diagenetic processes controlled the distribution of clay paragenesis shown to be of high importance for the understanding of the basin's burial history and geotectonic development. Materials acquired for this study stem from the siliciclastic fluvio-lacustrine-deltaic, petroleum bearing, Early Cretaceous Dentale and Gamba formations cored by two respective wells at depths of ~1500m. Sampled materials were analysed by X-ray diffraction, automated electron microscopy, and inductively coupled plasma mass spectrometry in order to reconstruct eogenetic and mesogenetic variations directing the formation of clay assemblages in the basin. The clay contents in both cores consist of authigenic mixed-layer minerals like illite-smectite, chlorite-smectite and berthierine-chlorite, and some minor detrital illite/mica and chlorite. I-Sm and C-Sm phase chemistry implied that the original dioctahedral (montmorillonite to beidellite) and trioctahedral (saponite) smectite precursors formed out of acid volcanic feedstock during eogenesis. Different magmatic fractionation degrees, from rhyodacite to trachyandesite, reflected in the uniform REE curves of volcanic glass conform to an active geotectonic development of the Cretaceous margins of Africa. Mesogenesis led to the decrease of smectite and formation of mixed-layered phases; I-Sm composition showed maximal burial depths of sediments to be ~1000m and ~500m deeper than today for Gamba and Dentale sediments, respectively. Besides, temperature, a major role in the formation of mixed-layer minerals had the porosity of sediments and geochemistry of smectitic precursors. Thus, Fe-Mg smectite showed higher thermal stability and lower rates of transformations in non-expanding clays during burial compared to Al-rich smectite. Different burial histories of sediments from the two cores can be attributed to rift-related normal faulting and subsequent differential denudation.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.09.032
      Issue No: Vol. 134 (2016)
  • Chlorite geothermometry applied to massive and oscillatory-zoned radiated
    • Authors: Darío Chinchilla; Xabier Arroyo; Raúl Merinero; Rubén Piña; Fernando Nieto; Lorena Ortega; Rosario Lunar
      Pages: 210 - 220
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 3
      Author(s): Darío Chinchilla, Xabier Arroyo, Raúl Merinero, Rubén Piña, Fernando Nieto, Lorena Ortega, Rosario Lunar
      Two textural types of chlorite are identified in the mineralised veins at the Patricia Zn-Pb-Ag epithermal ore deposit (NE, Chile): massive and oscillatory-zoned radiated chlorites. Three main stages of mineralisation have been defined in the Patricia deposit: (1) pre-ore stage, (2) base-metal stage which is divided into two substages: substage 2a and substage 2b and (3) post-ore stage. Both types of chlorite are classified as chamosite and occur coeval to the sphalerite precipitation during the substage 2a. Massive chlorite shows an average content of 33wt.% FeO, 4.9wt.% MnO, and 4wt.% MgO. Oscillatory zoning in radiated chlorites consists of concentric bands with different contents on FeO (from 26.45 to 41.41wt.%), MgO (from 1.7 to 5.44wt.%) and MnO (from 1.7 to 9.32wt.%). Four different chlorite geothermometers based on the system SiO2-Al2O3-FeO-MgO-H2O were applied to both types of chlorites. The temperature estimations are in agreement with temperatures data of fluid inclusions previously measured in sphalerite of the sub-stage 2a. Despite the high content in Mn of chlorites, the study confirms the applicability of the chlorite geothermometers without the knowledge of the Fe3+/Fe ratio in low-pressure paragenesis and its usefulness as an important tool for characterising the thermal conditions in epithermal ore deposits.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.10.013
      Issue No: Vol. 134 (2016)
  • Illitization sequence controlled by temperature in volcanic geothermal
           systems: The Tinguiririca geothermal field, Andean Cordillera, Central
    • Authors: Mercedes Vazquez; Blanca Bauluz; Fernando Nieto; Diego Morata
      Pages: 221 - 234
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 3
      Author(s): Mercedes Vazquez, Blanca Bauluz, Fernando Nieto, Diego Morata

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.04.011
      Issue No: Vol. 134 (2016)
  • Hydrothermal alteration of chlorite to randomly interstratified
           corrensite-chlorite: Geological evidence from the Oligocene Smrekovec
           Volcanic Complex, Slovenia
    • Authors: Polona Kralj
      Pages: 235 - 245
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 3
      Author(s): Polona Kralj
      Chlorite, ordered mixed-layer chlorite-smectites, laumontite, quartz and albite are the most widespread alteration assemblage in cone-building and near-vent successions of lavas, autoclastic, pyroclastic and resedimented volcaniclastic deposits of the Oligocene Smrekovec Volcanic Complex, Slovenia. Randomly interstratified corrensite-chlorite with ~70–80% of corrensite layers (R0 Cr-Ch) is less common in occurrence and associated either with clinoptilolite and heulandite in fine-grained vitric tuffs, or with prehnite, laumontite, actinolite, analcime and albite in extensively altered and/or fractured host-rocks. The assemblage with clinoptilolite and heulandite indicates the temperatures of formation of <~120°C and can be regarded as intermediate in the prograde alteration process of volcanic glass that leads in progressively increasing temperature regime to the formation of chlorite, laumontite, prehnite and albite. The assemblage of R0 Cr-Ch, prehnite, laumontite and actinolite developed in different superimposed temperature regimes and/or stages of hydrothermal activity related to the emplacement and subsequent gradual cooling of the Kramarica Sill. The formation of prehnite and actinolite signifies the highest-temperature conditions attaining up to ~300°C. Laumontite and R0 Cr-Ch extensively developed during the cooling period and as a result of the incursion of alkaline Ca-Mg hydrothermal fluids that possibly evolved from deep ground-waters convecting through Triassic dolomite in the basement of the submarine Smrekovec stratovolcano-hosted hydrothermal system.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.10.025
      Issue No: Vol. 134 (2016)
  • Very low-grade secondary minerals as indicators of palaeo-hydrothermal
           systems in the Upper Cretaceous volcanic succession of Hannah Point,
           Livingston Island, Antarctica
    • Authors: Joaquin Bastias; Francisco Fuentes; Luis Aguirre; Francisco Hervé; Alain Demant; Katja Deckart; Teresa Torres
      Pages: 246 - 256
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 3
      Author(s): Joaquin Bastias, Francisco Fuentes, Luis Aguirre, Francisco Hervé, Alain Demant, Katja Deckart, Teresa Torres
      The Upper Cretaceous basic volcanic succession in Hannah Point, Livingston Island, Antarctica, presents a widespread occurrence of very low-grade secondary minerals. They occur filling amygdules, veins and veinlets, and replacing phenocrysts and groundmass/matrix. The paragenetic associations include minerals such as laumontite, heulandite, stilbite and clinoptilolite; mafic phyllosilicates corresponding to chlorite and smectite mixed layers (compositions ranging from 57% to 84% of chlorite), albite, calcite and minor celadonite. The mineral assemblages indicate, based on laboratory and field studies, these mineral paragenesis temperatures of 150–200°C and pressures of 600–1.800bars, which agrees with the calculated equilibrium temperatures of 160–190°C, using chlorite geothermometry. These burial pressures, which were estimated from paragenesis, cannot be attained considering the present thickness of 500m of the sequence, because at least 1km of erosion is required to produce the mineral associations. Based on textural evidence, three successive stages are proposed to explain the genesis of the secondary minerals: (1) mafic phyllosilicates±celadonite, (2) zeolites and (3) calcite. The characteristics of these stages point to a regional burial metamorphism (stage 1) superimposed by hydrothermal alteration (stages 2 and 3). The mineral paragenetical evolution can be used as a proxy for the prospection of modern geothermal reservoirs by allowing the identification of hydrothermal alteration processes and burial metamorphism.

      PubDate: 2016-11-19T07:27:05Z
      DOI: 10.1016/j.clay.2016.07.025
      Issue No: Vol. 134 (2016)
  • Reaction kinetics of molecular aggregation of rhodamine 123 in colloids
           with synthetic saponite nanoparticles
    • Authors: Juraj
      Abstract: Publication date: December 2016
      Source:Applied Clay Science, Volume 134, Part 2
      Author(s): Tímea Baranyaiová, Juraj Bujdák
      The reaction kinetics of the molecular aggregation of rhodamine 123 in the colloids of synthetic saponite (Sumecton, Kunimine, Japan) was measured using a UV–Vis spectrophotometer equipped with a diode array detector with fast sampling and combined with a thermostatic stopped-flow device. The colloids exhibited a very small tendency to produce dye molecular aggregates, which can be explained by the low layer charge of saponite. Nevertheless chemometric methods, including principal component analysis and multivariate curve resolution, were able to sensitively identify spectral components. The reaction kinetics of dye aggregation followed the model, which was mathematically described by two-phase exponential functions, which indicated the presence of two parallel first-order reactions. Oblique aggregates were formed, characterized by approximate right angles between interacting transition moments. Another reaction, which was assigned to the structural changes of the aggregates, was detected after longer reaction times. The total span of the reaction was relatively low (~5%). The reaction was relatively fast, giving half-lives in the range 8–10s. Reaction kinetics parameters can be useful for the characterization of similar reactions occurring in dye/clay mineral colloidal systems.
      Graphical abstract image

      PubDate: 2016-11-19T07:27:05Z
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