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PHYSICS (553 journals)            First | 1 2 3 4 5 6 | Last

Journal of Research in Physics     Open Access  
Journal of Rheology     Full-text available via subscription   (Followers: 5)
Journal of Romance Studies     Full-text available via subscription   (Followers: 2)
Journal of Sandwich Structures and Materials     Hybrid Journal   (Followers: 1)
Journal of Scientific Research     Open Access   (Followers: 1)
Journal of Semiconductors     Full-text available via subscription   (Followers: 2)
Journal of Sensors     Open Access   (Followers: 7)
Journal of Sol-Gel Science and Technology     Hybrid Journal   (Followers: 2)
Journal of Solid State Lighting     Open Access  
Journal of Solid State Physics     Open Access  
Journal of Spectroscopy     Full-text available via subscription  
Journal of Superconductivity and Novel Magnetism     Partially Free   (Followers: 1)
Journal of Synchrotron Radiation     Hybrid Journal   (Followers: 1)
Journal of Testing and Evaluation     Full-text available via subscription   (Followers: 10)
Journal of the American Society for Mass Spectrometry     Hybrid Journal   (Followers: 17)
Journal of the Brazilian Society of Mechanical Sciences     Open Access   (Followers: 1)
Journal of the ICRU     Hybrid Journal  
Journal of the Korean Physical Society     Partially Free   (Followers: 1)
Journal of Theoretical and Applied Physics     Open Access   (Followers: 1)
Journal of Tissue Engineering     Open Access   (Followers: 4)
Journal of Ultrasound in Medicine     Full-text available via subscription   (Followers: 3)
Journal of Vibration and Control     Hybrid Journal   (Followers: 18)
Journal of Visualization     Hybrid Journal   (Followers: 2)
Journal of Zhejiang University SCIENCE A     Hybrid Journal  
Jurnal Penelitian Sains (JPS)     Open Access  
Language Learning Journal     Hybrid Journal   (Followers: 12)
Lasers in Surgery and Medicine     Hybrid Journal  
Latvian Journal of Physics and Technical Sciences     Open Access  
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Les Houches Summer School Proceedings     Full-text available via subscription  
Letters in Mathematical Physics     Hybrid Journal   (Followers: 3)
Light : Science & Applications     Open Access  
Living Reviews in Relativity     Open Access  
Living Reviews in Solar Physics     Open Access  
Lubrication Science     Hybrid Journal  
Macalester Journal of Physics and Astronomy     Open Access  
Machining Science and Technology: An International Journal     Hybrid Journal   (Followers: 2)
Magnetic Resonance Materials in Physics, Biology and Medicine     Hybrid Journal   (Followers: 1)
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 3)
MAPAN     Hybrid Journal  
Mass Spectrometry Reviews     Hybrid Journal   (Followers: 17)
Matéria (Rio de Janeiro)     Open Access   (Followers: 1)
Materials & Design     Hybrid Journal   (Followers: 30)
Materials at High Temperatures     Full-text available via subscription   (Followers: 4)
Materials Chemistry and Physics     Full-text available via subscription   (Followers: 13)
Materials Research     Open Access   (Followers: 7)
Materials Research Bulletin     Hybrid Journal   (Followers: 18)
Materials Science     Hybrid Journal   (Followers: 7)
Materials Science and Engineering: A     Hybrid Journal   (Followers: 35)
Materials Science and Engineering: B     Hybrid Journal   (Followers: 17)
Materials Science and Engineering: C     Hybrid Journal   (Followers: 16)
Materials Science and Engineering: R: Reports     Hybrid Journal   (Followers: 12)
Matériaux & Techniques     Full-text available via subscription   (Followers: 1)
Mathematical Physics, Analysis and Geometry     Hybrid Journal   (Followers: 1)
Mathematics and Mechanics of Solids     Hybrid Journal   (Followers: 2)
Meccanica     Hybrid Journal   (Followers: 1)
Mechanics of Advanced Materials and Structures     Hybrid Journal   (Followers: 3)
Mechanics of Materials     Hybrid Journal   (Followers: 12)
Mechanics of Time-Dependent Materials     Hybrid Journal   (Followers: 1)
Mechanics Research Communications     Hybrid Journal   (Followers: 2)
Metamaterials     Hybrid Journal   (Followers: 2)
Micro and Nano Systems Letters     Open Access   (Followers: 4)
Microfluidics and Nanofluidics     Hybrid Journal   (Followers: 9)
Microporous and Mesoporous Materials     Hybrid Journal   (Followers: 3)
Modern Instrumentation     Open Access   (Followers: 3)
Modern Physics Letters A     Hybrid Journal   (Followers: 1)
Modern Physics Letters B     Hybrid Journal  
Molecular Diversity     Hybrid Journal  
Moscow University Physics Bulletin     Hybrid Journal  
Multibody System Dynamics     Hybrid Journal   (Followers: 1)
NANO     Hybrid Journal   (Followers: 8)
Nano Letters     Full-text available via subscription   (Followers: 48)
Nano Reviews     Open Access   (Followers: 17)
NanoBioImaging     Open Access  
Nanomechanics     Open Access  
Nanoscale and Microscale Thermophysical Engineering     Hybrid Journal   (Followers: 3)
Nanoscale Research Letters     Open Access   (Followers: 4)
Nanospectroscopy     Open Access  
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 15)
Natural Science     Open Access   (Followers: 9)
Nature Communications     Hybrid Journal   (Followers: 42)
Nature Materials     Full-text available via subscription   (Followers: 45)
Nature Physics     Full-text available via subscription   (Followers: 26)
NDT & E International     Hybrid Journal   (Followers: 14)
NEUTRINO     Open Access  
Neutron News     Hybrid Journal  
New Journal of Physics     Open Access   (Followers: 7)
Niels Bohr Collected Works     Full-text available via subscription  
Noise & Vibration Worldwide     Full-text available via subscription   (Followers: 5)
Noise Notes     Full-text available via subscription   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 6)
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin     Hybrid Journal   (Followers: 4)
Nuclear Engineering and Design     Hybrid Journal   (Followers: 12)
Nuclear Medicine and Biology     Hybrid Journal   (Followers: 1)
Nuclear Receptor     Full-text available via subscription   (Followers: 1)
Open Journal of Biophysics     Open Access   (Followers: 1)
Open Journal of Fluid Dynamics     Open Access   (Followers: 3)
Open Journal of Microphysics     Open Access  
Optical Communications and Networking, IEEE/OSA Journal of     Hybrid Journal   (Followers: 4)

  First | 1 2 3 4 5 6 | Last

Journal Cover Microporous and Mesoporous Materials     [SJR: 1.306]   [H-I: 93]
   [5 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1387-1811
   Published by Elsevier Homepage  [2582 journals]
  • Analysis of optical and thermal properties of thermally oxidized
           mesoporous silicon layers
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): D. Ben Hlel , I. Gaied , N. Sghaier , A. Gharbi , H. Fitouri , N. Yacoubi
      In this paper we will report the evolution of optical and thermal properties of thermally oxidized mesoporous silicon layers. The samples were manufactured by the conventional electrochemical anodization. The modification process including thermally oxidized samples in dry oxygen at different temperatures and duration was conducted. After treatment, the products were characterized by Spectral Reflectance in the wavelength range of 200–1100nm which served to exclude an important decrease of the optical loss with temperature and duration of oxidation. We noticed that thermal oxidation improved the absorption of the UV light and led to a significant decrease of the average reflectivity. The band gap energy was performed by the Photoluminescence spectroscopy under an excitation at 325nm and showed a broad emission centered at around 2.1eV for all the samples. Furthermore, thermal conductivity and thermal diffusivity were determined by Photothermal Deflection Technique by comparing the experimental curves of normalized amplitude and phase of the photothermal signal to the corresponding theoretical ones. It was also found that the increase of both temperature and time of the thermal oxidation process affect the thermal properties of these layers.
      Graphical abstract image Highlights Normalized experimental reflectivity of the thermally oxidized porous silicon films.

      PubDate: 2015-01-19T16:34:09Z
       
  • A novel application of mesoporous silica nanospheres on effective
           retention and delivery of lubricating oil
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Xiangyuan Ye , Jinqing Wang , Honggang Wang , Shengrong Yang
      Mesoporous silica nanospheres (MSNs), with neat morphology, large Brunauer–Emmett–Teller (BET) surface area and uniform pore diameter, have been synthesized firstly, and then the liquid paraffin as lubricating oil is poured into the pores of the MSNs via a simple wet impregnation method to form paraffin-containing MSNs (abbreviated as PMSNs). The tribological tests are carried out under three different loads (1.0, 1.5, and 2.0N) by sliding a steel ball (φ =6mm) against PMSNs thin films spin-coated on glass slides. The results indicate that the friction coefficient of glass slide reduces greatly from 0.7 to 0.09 due to the effective release of liquid paraffin preserved inside the pores of MSNs under these loads. Meantime, the corresponding wear volumes of glass slides also decrease greatly after the formation of the PMSNs film. As a result, the present work lights a pharos to utilize lubricating oil more effectively via releasing oil preserved inside the pores of the MSNs.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Green and efficient synthesis of adipic acid from cyclohexene over
           recyclable H3PW4O24/PEHA/ZrSBA-15 with platelet morphology
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Lingyan Meng , Shangru Zhai , Zuchen Sun , Feng Zhang , Zuoyi Xiao , Qingda An
      Designing a green synthesis system of adipic acid is important to achieve sustainable development of adipic acid-derived industries. A green and efficient synthesis of adipic acid by using one-step oxidative cleavage of cyclohexene over recyclable H3PW4O24/PEHA/ZrSBA-15 is presented in this paper. The synergic effect of Zr-ions modified the acidic framework and auxiliary PEHA molecules toward high dispersion and stabilization of active clusters. These clusters endowed the resulting nanocomposites with unexceptional reusability under employed reaction conditions. Standard characterization techniques, namely, N2 sorption, XRD, FT-IR, TEM, XPS, 1H-NMR, and ICP-AES, were performed to establish the coordinated internal ordered framework of the nanocomposite with platelet morphology. The superiority of layer-by-layer deposition strategy has been proved accordingly. Detailed reaction parameters were screened for the optimization of a catalytic system. Compared with the properties of the catalyst H3PW12O40/PEHA/ZrSBA-15, which is prepared through identical pathways, the properties of the reactive PW4 clusters with strengthened stabilization are favorable. Therefore, excellent catalytic performance of adipic acid yield (∼90.9%) was observed along with efficient recyclability during five reaction cycles.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Glucose-based carbon coated MnOx hierarchical architectures with enhanced
           photostability and photocatalytic activity
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Junli Zhou , Xiaodan Zhang , Wei Mu , Yulin Deng , Ting Lin , Wei Song , Lin Yu
      Carbon coated MnO x (MnO x @C) with various novel and complex 3D hierarchical architectures self-assembled from different building blocks were successfully synthesized by a hydrothermal method in glucose-mediated processes. The morphology modulation of MnO x @C could be easily realized simply by adjusting the amount of glucose added into the reaction system. The formation mechanisms for different hierarchical architectures were proposed on the basis of time-dependent experiments. An investigation on UV–visible absorption spectroscopy revealed that the as-synthesized MnO x @C expanded the light absorption from UV region to visible light region. Specifically, when 0.45g of glucose was used, the samples (ε-MnO2-C-0.45 and MnO-C-0.45) obtained from different calcination process exhibited the semiconductor feature with a band gap of 1.9eV and 1.84eV, respectively. In addition, the carbon coating on MnO x provided good chemical protection for MnO x and greatly improved its photostability. The laser heating effect for ε-MnO2@C structures were also studied. The ε-MnO2@C structures could be stable at a high laser power of 1200μW, which suggested significantly enhanced photostability. When used for decolorization of methyl orange under visible light (λ ⩾420nm), the MnO x @C structures exhibited much higher activities than pure MnO x . The decolorization rate for the optimum catalyst ε-MnO2-C-0.45 could reach above 90% within 10min.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Structure, reactivity and mechanical properties of water ultra-confined in
           the ordered crystal: A case study of jennite
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Dongshuai Hou , Tiejun Zhao , Zuquan Jin , Zongjin Li
      Jennite is an important structural prototype of C–S–H gel that is the major component of the cement hydrate. The structure, dynamics and mechanical properties of jennite were investigated by reactive force field molecular dynamics simulation. Water molecules, confined between the neighboring calcium silicate sheets, dissociate and form the Si–OH bonds with the oxygen atoms in the bridging silicate tetrahedron, which is consistent with the strong signal of Si–OH linkage from NMR testing (Cong and Kirkpatrick, 1996) [1]. Dynamically, the high diffusion rate and the dissociation reaction of water molecules reduce the stability in the interlayer region. Additionally, uniaxial tensile testing, applied to the jennite structure in the x, y and z direction, exhibited the an-isotropic nature of the layered crystal. While Si–O bonds, acting in a skeleton role, contribute to the mechanical behavior in the y direction, the unstable H-bonds connectivity weakens the tensile strength and stiffness in the z direction. More importantly, the reactive force field accompanied together both the mechanical response and chemical response during the large tensile deformation process. On the one hand, the silicate chains de-polymerize to enhance the loading resistance and on the other hand, water molecules, attacking the Si–O and Ca–O bonds, dissociate into hydroxyls, which are detrimental to the cohesive force development.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Synthesis and stability of zeolitic imidazolate framework-68 membranes
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Alexandra Kasik , Xueliang Dong , Y.S. Lin
      Large pore zeolitic imidazolate framework (ZIF) membranes offer potential for separation of gases with different adsorption affinity on ZIF crystals and separation of liquid molecules by molecular sieving. In this work continuous, highly crystalline, largely c-oriented ZIF-68 membranes were reproducibly synthesized on macroporous zinc oxide supports by the reactive seeding method. The membranes were roughly 50microns thick and the single component gas permeance measurements obtained adhered to Knudsen diffusion, indicating the presence of limited nonselective defects. The membranes were found to be highly stable at room temperature and ambient conditions, although immersion in water at room temperature and 100°C caused irreparable damage to the ZIF-68 crystallinity. Immersion in organic solvents did not render the crystallinity notably altered. A prolonged p-xylene pervaporation run indicated that ZIF-68 membranes were susceptible to fouling, by showing an approximately 55% decrease in p-xylene pervaporation flux from when the membrane was fresh to the second data point tested at 4h. The extent of fouling equilibrated after 4h on-stream and the pervaporation flux remained constant throughout the remainder of testing. The membrane crystallinity was not degraded by p-xylene pervaporation.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Binding of CpG oligodeoxynucleotides to mesoporous silica nanoparticles
           for enhancing delivery efficiency
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Cuilian Tao , Yufang Zhu , Xianglan Li , Nobutaka Hanagata
      We developed a potential cytosine-phosphate-guanosine oligodeoxynucleotides (CpG ODN) delivery system by binding of CpG ODN onto aminated mesoporous silica nanoparticles (MSNs) to form CpG/MSN-NH2 complexes for Toll-like receptor 9 (TLR9)-mediated induction of cytokines. Serum stability, in vitro cytotoxicity, cellular uptake, and interleukin-6 (IL-6) induction of CpG/MSN-NH2 complexes were investigated. The results showed that MSN-NH2 nanoparticles had no cytotoxicity to Raw 264.7 cells, and binding of CpG ODN to MSN-NH2 nanoparticles enhanced serum stability of CpG ODN due to the protection by nanoparticles. Furthermore, CpG/MSN-NH2 complexes could be efficiently taken up by cells due to small particle size and good dispersity. Most importantly, CpG/MSN-NH2 complexes significantly enhanced the level of IL-6 induction, stimulated by interaction between CpG ODN and TLR9 in endolysosomes. Therefore, MSNs would be a promising carrier for enhancing the delivery efficiency of CpG ODN.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Patterning silicalite-1 films using carbon dioxide laser ablation
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Swarnasri Mandal , Dylan Macoubrie , Heather K. Hunt
      Nanostructured materials represent an intriguing foundation on which to build new devices for applications in electronics, photonics, energy storage, and biological/chemical analysis. For example, porous, nanostructured materials, such as pure-silica zeolite films, have been used to form 2D and 3D structures for building intricate micro-scale assemblies for light-harvesting, sensing, and microreactor applications. The standard methods used to pattern such devices and features from nanostructured materials are based on either typical microfabrication techniques, which involve either several complex and time-consuming steps, and can result in pore clogging, or the organization of pre-formed seeds/crystals uniformly arranged on the substrate by chemical or physical linkages, which requires precise control and positioning. Here, we present a simple, flexible alternative to both techniques: CO2 laser ablation. We demonstrate the effects of this technique on a model zeolite thin film system, pure-silica MFI (silicalite-1), to evaluate its potential for patterning complex, multicrystalline, nanostructured materials. We use SEM and XRD to determine the crystallinity, film thickness, surface coverage, crystal size, and crystal habit of the films pre- and post-patterning. Using this technique, we demonstrate that it is possible to make 3D structures in these films, such as channels of varying width (82–611.98μm), depth (2.58–7.13μm), separation distance (minimum 25μm), and edge effects, by varying laser power, spot size, and raster speed. This work introduces a one-step, rapid technique to pattern materials with specific framework structures and subnanometer pore sizes, thus broadening their potential usage in areas that require patterned, micro-scale features.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • HF-assisted synthesis of ultra-microporous [Mg3(OOCH)6] frameworks for
           selective adsorption of CH4 over N2
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Jiangliang Hu , Tianjun Sun , Xinyu Ren , Shudong Wang
      Ultra-microporous [Mg3(OOCH)6] frameworks with different uniform shapes, were synthesized via a facile coordination modulation method, in which HF was used as a modulator to promote the growth of [Mg3(OOCH)6] crystals. The as-prepared [Mg3(OOCH)6] frameworks were scrutinized and evaluated the CH4 adsorption capacity and selectivity over N2 by pure gas adsorption and breakthrough experiments. The [Mg3(OOCH)6] frameworks exhibit preferential adsorption of CH4 over N2, and much higher CH4 adsorption capacity (up to 0.74mmol/g) by comparison with conventional zeolites. It has been confirmed that the equilibrium selectivities of [Mg3(OOCH)6] frameworks are shape dependent, and the uniform prism-like framework with size of 100μm has the highest selectivity up to 5.5 at 298K. These results suggest that achieving the optimal coupling of polarizability and structure of [Mg3(OOCH)6] framework is key factor to obtain a high selectivity for the separation of CH4/N2 mixture.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Pd-doped β-Bi2O3/Bi2Sn2O7 hybrid nanocomposites for photocatalytic
           fluorene oxidation: A green approach for the synthesis of
           fluorenone/fluorenol mixture
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Mohamed Mokhtar Mohamed , Saleh A. Ahmed
      Bismuth oxide, tin oxide and Pd metal (Pd/SnBi3SG) hybrids, synthesized via sol–gel technique while employing polyethylene glycol template at a ratio of 3 (Bi/Sn=3) were tested toward the photocatalytic oxidation of fluorene under ultraviolet and visible light irradiations in comparison with Pd/BiSG and Pd free SnBi3SG photocatalysts. These catalysts were characterized using X-ray diffraction (XRD), UV–vis diffuse reflectance (DRUV–vis), N2 sorptiometry, Raman spectroscopy, transmission electron microscopy (TEM) and GC–MS technique, which used for analyzing the photo-oxidation products. The actual photocatalyst exhibited the highest activity (100% conversion, TOF≈9.4×10− 6 s− 1, fluorenone/fluorenol=3/1) following oxygen flushing for 30min (35ml/min) before UV irradiation. This was mainly due to the close proximity between β-Bi2O3 and Bi2Sn2O7 heterojunction as well as increasing the mesoporosity margin comparatively. On the other hand, the Pd/BiSG catalyst that exhibited smaller crystallite size (20nm vs. 44nm) and higher surface area (21.0 vs. 12.0m2/g) than Pd/SnBi3SG indicated lower activity (Pd/BiSG, 72% conv.). This highlights the importance of the modified electronic structure of Pd/SnBi3SG in designing efficient charge separation as well as high quantum yield value (Φ ∼0.1±0.05) exceeding that of Pd/BiSG (3×10−2) and SnBi3SG (10−2) photocatalysts. The catalytic behavior and mechanism, reactivity–structure relationship and recyclable use of the hybrid photocatalysts have been thoroughly examined. An indirect chemical probe method using active species scavengers elucidated that the photo-oxidation mechanism was proceeded via holes and O2 − moieties rather than singlet oxygen moieties.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Phosphate-assisted one-pot synthesis of silver phosphate–mesoporous
           silica composite from sodium silicate and silver nitrate
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Jiu-Yang Yang , Chun-Ming Zheng , Yan-Qing Wang , Ming-Lin Guo
      A facile one-pot method for silver phosphate–mesoporous silica composite was reported. In the synthesis procedure, sodium silicate was firstly added dropwise to acidic Pluronic P123 and silver nitrate aqueous solution, followed by addition of phosphate to adjust the pH to near-neutral. Through the salting-out and flocculation effect of phosphate, tiny silver phosphate particles and silicate oligomers were formed and mixed together to build the composite material. It was a new type of mesoporous silica composite which had a structure similar to SBA-15. And it was found to have higher photocatalytic activity than pure silver phosphate in the degradation of methyl orange under ultraviolet light irradiation.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Solid-state dealumination of zeolites for use as catalysts in alcohol
           dehydration
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Júlia M. Müller , Gustavo C. Mesquita , Sheila M. Franco , Luciana D. Borges , Julio L. de Macedo , José A. Dias , Sílvia C.L. Dias
      The dealumination of zeolites has been studied to tune acidity, resulting in enhanced catalytic efficiency. MOR, FER, and ZSM-5 were dealuminated to remove 5, 10, 15, or 20mol% of Al with (NH4)2SiF6 (solid-state reaction at 80°C). XRD, SEM, and FT-IR showed structural maintenance. Aluminum removal was confirmed by the total Si/Al ratio (XRF and AAS) and 27Al MAS NMR. The dealuminated samples were tested in the dehydration of different alcohols and compared to the protonic parent zeolites. Dealuminated MOR samples exhibited a decrease in coke formation (maximum decrease of 18.3%, 18.2%, and 6.1% for methanol, ethanol, and 1-propanol dehydration, respectively), and an increase in conversion values (maximum increase of 29.0%, 13.9%, and 6.2% for methanol, ethanol, and 1-propanol dehydration). H-FER/20% showed an improvement in methanol (19.9%) and ethanol (3.8%) conversions and a reduction of coke (decrease of 8.6% and 5.6%, respectively), corroborating the highest value of acid sites (0.73mmolg−1). All catalysts showed 100% selectivity to each desired product. The mechanisms for all dehydrations were related to the presence of Brønsted acid sites. Methanol dehydration might involve the generation of methoxonion ion, and ethoxy groups might be formed for ethanol conversion. For ZSM-5, Lewis acid sites may also participate in the elimination mechanism. High reaction temperature (300°C) favored intramolecular dehydration to ethylene, avoiding formation of diethyl ether and oligomers. Structural defects on H-ZSM-5/15% could facilitate the access of 1-propanol to active sites, leading to the best combination of TON (0.67), conversion (100%), and coke formation (0.35%).
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Comparative adsorption study of EVS-10 and ETS-10
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Farnaz Mani , James A. Sawada , Steven M. Kuznicki
      Vanadium silicate EVS-10 is analogous to ETS-10 except that vanadium completely substitutes for titanium in the structure. This study compares the structural and adsorptive characteristics of EVS-10 with ETS-10. The structures were characterized by powder XRD, EDX, argon physisorption, and SEM/TEM. The Henry law constants and heats of adsorption were calculated for both adsorbents from low pressure adsorption data using CH4, C2H6, C2H4, N2, O2, and CO2 for pressures up to 100kPa and temperatures of 303, 323, and 343K. The adsorption data were fit using Langmuir, Toth, and Redlich–Peterson isotherms. The best model was selected based on the quality of fit to the data and how closely the model predicted the saturation concentration compared to the value calculated from the measured pore volume data. The structural properties for EVS-10 are almost indistinguishable from ETS-10. The adsorption data reflects this similarity in that both adsorbents have similar heats of adsorption and selectivities for a wide range of gases. These results suggest that heteroatom substitution in ETS-10 does not necessarily affect its adsorption properties if the framework dimensions and composition remain similar.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Shaping amine-based solid CO2 adsorbents: Effects of pelletization
           pressure on the physical and chemical properties
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Fateme Rezaei , Miles A. Sakwa-Novak , Sumit Bali , Daniel M. Duncanson , Christopher W. Jones
      Amine-based solid adsorbents are promising candidates for the separation of CO2 from dilute gas streams. Here we report the effect of pelletization pressure on the physical and chemical properties of an array of supported amine adsorbents, based on mesoporous silica and γ-alumina supports. The virgin powders based on poly(ethyleneimine) (PEI) and 3-aminopropyltrimethoxysilane (APS) functionalized oxides are pressed at 1000 and 5000psig pressure to form self-supporting pellets and their physical and chemical properties are compared. No change in chemical structure of the adsorbents is observed after pelletization, though the porosity of each material changes to some degree. Of the three mesoporous supports examined in this study, the commercial porous silica is the most stable support for both class 1 and class 2 adsorbents, whereas lab synthesized mesoporous SBA-15 silica and lab synthesized mesoporous γ-alumina are found to be the least stable supports for class 1 and class 2 adsorbents, respectively. The CO2 uptake results show a significant drop in equilibrium capacity for the pellets pressed at 5000psig, regardless of the support used, while the 1000psig pellets retain their capacity and show comparable performance to their powder counterparts. CO2 breakthrough experiments suggest an increase in mass transfer resistance for the pellet samples as compared with virgin powders, resulting in the dispersion of the concentration fronts during CO2 breakthrough using a fixed bed. These findings suggest that shaping solid supported amine adsorbents into binderless pellets requires pressing the powders at low to moderate pressures to ensure that these materials retain their performance in processes that require pelletized samples.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Hierarchical porous materials based on nanoscale metal-organic frameworks
           dominated with permanent interparticle porosity
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Xun Liu , Zhen-Qi Shen , Hui-Hui Xiong , Yan Chen , Xiao-Nan Wang , Hao-Qiu Li , Yan-Tao Li , Ke-Hui Cui , Yun-Qi Tian
      In order to extensively synthesize mesoporous metal-organic frameworks (mesoMOFs), we developed a strategy to construct permanent interparticle porosity based on nanoscale metal-organic frameworks (NMOFs). Using the strategy, we have attained a series of interparticle porosity dominated mesoMOFs (IPD-mesoMOFs) from six MOF-types with MIl-100, MIL-53, HKUST-1, DUT-5, DUT-4 and MIL-101(Cr) (termed as IPD-mesoMOF-1, -2, -3, -4, -5 and -6) structure, respectively. All members of this series are not only comparable to inorganic mesoporous materials to have the tunable mesopore apertures varying from a few nanometers to over a dozen nanometers, but also superior to the inorganic counterparts to remain hierarchical porosity with higher surface area (up to 2130m2 g− 1), larger mesopore volume (the highest to 2.59cm3 g−1) and optional micro-porosity of diverse crystalline structures. The large mesopore apertures and rich carboxyl residues on the mesopore-walls also allow the IPD-mesoMOF series to accommodate large organic and inorganic molecules, especially to immobilize the bulky natural protein, such as, hemoglobin.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Acidic mesostructured aluminosilicates assembled from economic acidic
           template characterized by catalytic cracking reactions
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Mohamed A. Betiha , Mohamed F. Menoufy , Ahmad M. Al-Sabagh , Hassan M.A. Hassan , Sawsan A. Mahmoud
      Mesoporous 3D aluminosilicates, denoted as AlMFA-8, were one-pot synthesized with two different nSi/nAl ratios using linear alkylbenzene sulfonic acid, LASH, as template. The AlMFA-8 materials were characterized using XRD, N2-adsoption, SEM, HRTEM, XRF, XPS and FT-IR. The results showed that AlMFA-8(x) has large-pore mesoporous solids. The pore volume increases from 1.28 to 1.45cm3/g without significant concomitant decrease of the surface area (≈659m2/g). On the other hand, AlSBA-15(x) materials with the same nSi/nAl ratios were one-pot synthesized by adjusting the molar of nH2O/nHCl in synthesis gel at 276 using P123 as template. The surface acidity of AlMFA-8(x) and AlSBA-15(x) were evaluated and confirmed by NH3-TPD, Pyr-FT-IR, TGA-wax-catalytic cracking, 1,3,5-triisopropylbenzene and n-hexadecane cracking. In addition, commercial silica–alumina (CSi–Al) was characterized and its catalytic activity is compared with the different acid mediated synthesis route, AlMFA-8(x) and AlSBA-15(x). The AlMFA-8(x) showed the higher activity under equivalent conditions in comparison to AlSBA-15(x) and CSi–Al materials.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Effects of surface heterogeneity of cobalt oxyhydroxide/graphite oxide
           composites on reactive adsorption of hydrogen sulfide
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Marc Florent , Teresa J. Bandosz
      A high surface area cobalt oxyhydroxide and its composites with graphite oxide (GO) were prepared by a fast and simple procedure consisting of a precipitation followed by an oxidation with a strong oxidizer. The materials were tested as H2S reactive adsorbents at ambient conditions. Their structural properties and surface chemistry, before and after H2S exposure, were investigated using nitrogen adsorption, X-ray diffraction, infrared spectroscopy and thermal analysis. Results showed that the cobalt oxyhydroxide is a good H2S adsorbent. Even though the incorporation of a graphene-based phase slightly decreases the performance of cobalt oxyhydroxide, its presence promotes the retention of H2S oxidation product, SO2, on the surface. The reactive adsorption of H2S results in the formation of at least three different sulfur species underlying the complexity of the surface reactions. The detection of sulfates indicates that the oxidation is the main mechanism of H2S retention on the surface of these materials.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Editorial Board
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204




      PubDate: 2015-01-19T16:34:09Z
       
  • Imidazolium-based ionic liquids as novel organic SDA to synthesize
           high-silica Y zeolite
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Danhua Yuan , Dawei He , Shutao Xu , Zhijia Song , Mozhi Zhang , Yingxu Wei , Yanli He , Shuliang Xu , Zhongmin Liu , Yunpeng Xu
      Alkyl-substituted imidazolium-based ionic liquid as a novel type of organic structure-directing agent (SDA) was employed to synthesize high-silica Y zeolite with a SiO2/Al2O3 ratio of approximately 6.20–6.40. The XRD, SEM, BET and 27Al NMR characterizations showed that the products synthesized with the ionic liquids 1-ethyl-3-methylimidazolium bromide or 1-butyl-3-methylimidazolium bromide were highly crystalline pure phase Y zeolite. Moreover, the TG, TOC, XRF and 13C NMR results suggested that 1-ethyl-3-methylimidazolium or 1-butyl-3-methylimidazolium cations were trapped within the pores of the faujasite structure and played the role of structure-directing agents. 1-Ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium cations can partially replace the sodium cations to balance the negative charges of the zeolite framework, which facilitated the formation of a high SiO2/Al2O3 ratio faujasite structure.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Molybdenum(VI) complex with a tridentate Schiff base ligand immobilized on
           SBA-15 as effective catalysts in epoxidation of alkenes
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Jian Zhang , Pingping Jiang , Yirui Shen , Weijie Zhang , Xiaoting Li
      Two novel molybdenum(VI) tridentate Schiff base complexes supported onto modified mesoporous SBA-15 were prepared by a covalent grafting method, one of which involved the postsynthesis trimethylsilylation of Mo-FSAP-Cl-SBA-15 to remove the residual surface silanol groups. The prepared complex materials were characterized by FT-IR, XRD, SEM, TEM, 29Si CP–MAS-NMR, TGA, ICP-AES and nitrogen adsorption–desorption. Both two were active in the catalytic epoxidation of cyclohexene at 80°C using tert-butylhydroperoxide (TBHP) as oxidant and 1,2-dichloroethane as solvent. The catalytic activity of the heterogenized organo catalyst can be further enhanced by silylation of the residual Si–OH groups using Me3SiCl, due to the higher content of Mo active sites and better surface hydrophobicity. As a result, using the more efficient catalyst Mo-FSAP-CH3-Cl-SBA-15 for catalytic reaction, the conversion and selectivity were 94.38% and 91.63%, respectively, under the optimized condition. After being used five times, the conversion and selectivity of Mo-FSAP-CH3-Cl-SBA-15 were still above 80.00% and 90.00% indicating the good reusability of Mo-FSAP-CH3-Cl-SBA-15.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Influence of structural, textural and surface properties of mesostructured
           silica and aluminosilicate carriers on aminoglycoside uptake and in vitro
           delivery
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Daniela Berger , Laura Bajenaru , Silviu Nastase , Raul-Augustin Mitran , Cornel Munteanu , Cristian Matei
      This work assessed the influence of structural, textural and surface features of mesostructured silica and aluminosilicate carriers on aminoglycosides encapsulation and in vitro release. A series of pure and functionalized mesostructured silica, as well as aluminosilicates, which belong to MCM-41, MCM-48 and SBA-15 classes, and two aminoglycosides with related structure, amikacin and kanamycin as biologically-active molecules were employed in order to prepare drug delivery systems. No significant toxicity of studied mesoporous carriers on MEF cells after 72h of continuous exposure to 100μg/mL nanoparticles was noticed. The mesostructured supports and amikacin- and kanamycin-based hybrid samples were characterized by small- and wide-angle XRD, FT-IR spectroscopy, thermogravimetric analysis, and N2 sorption isotherms. The uptake values for all amikacin-based hybrids are higher than those for kanamycin counterparts. Moreover, the first antibiotic can be loaded on functionalized (with 3-aminopropyl or methyl groups) SBA-15-type materials, unlike the last drug. Amikacin loaded into the mesopores of AlSBA-15 and SBA-15 vehicles exhibited a slower delivery rate than from MCM-48 and functionalized SBA-15 materials. Different than amikacin-based hybrids, kanamycin loaded on aluminosilicates (AlMCM-41 and AlSBA-15) caused faster delivery, the highest value of drug cumulative release at 24h being obtained for AlMCM-41 support.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Solid-state 29Si and 27Al NMR studies of natural mesolite
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Bogdan Sulikowski
      A natural zeolite specimen from Pune, India, was studied using 1D (29Si, 27Al) and 2D (27Al) multi-quantum (MQ) solid-state NMR. The signals of silicon and alumina spectra were assigned using empirical relationships between the bilateral Si–O–Al angles in a zeolite framework and the corresponding chemical shifts. While three distinct signals of 29Si MAS NMR spectra at −86 to −89ppm were assigned to three single Si n (3Al) sites (n =2–4), the largest one at −95.5ppm was shown to be composed of the two Si environments, Si1(2Al) and Si5(2Al). A complex 27Al single-Bloch decay spectrum of mesolite could not be properly assigned without resorting to a 3MQ MAS NMR experiment. It was shown that three signals arising from 3 different crystallographic positions of the framework aluminum in mesolite could be discerned using the 27Al 3MQ MAS NMR spectra. The quadrupolar parameters of the three Al sites were obtained. Finally, treatment of mesolite with oxalic acid was carried out, leading to a partially dealuminated sample. Small, albeit selective, removal of aluminum predominantly from the T3 sites was observed upon dealumination.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Microwave-assisted hydrothermal synthesis of submicron ZSM-22 zeolites and
           their applications in light olefin production
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Oki Muraza , Adedigba Abdul-lateef , Teruoki Tago , Asep B.D. Nandiyanto , Hiroki Konno , Yuta Nakasaka , Zain H. Yamani , Takao Masuda
      There is an increased demand for facile and rapid synthesis of one-dimensional pore zeolites with controlled crystal size in the nanometer range. Here, we report for the first time, the rapid synthesis of ZSM-22 (TON) by using microwave-assisted hydrothermal synthesis (MAHyS) to control nucleation and growth. ZSM-22 crystals were synthesized rapidly in 24h (instead of 72h in conventional synthesis). Effect of synthesis time under microwave irradiation on the crystallinity of TON zeolites from 8 to 24h was investigated. The conventional hydrothermal synthesis was used for comparison. Under microwave-assisted synthesis, uniform crystal size with lower crystal aspect-ratio (length/width) was obtained and high agglomeration was prevented. Surface modification was applied by deposition of silica on the external surface of ZSM-22 using catalytic cracking of diphenyl silane. The protonated H-ZSM-22 prepared by the MAHyS and the surface-modified TON zeolites were applied in catalytic cracking of n-hexane. The modified MAHyS zeolites showed superior selectivity to propylene and lower selectivity to aromatics. Stability against deactivation was clearly observed over surface-modified ZSM-22 zeolites. The physico-chemical properties of modified zeolite-catalysts were characterized by using XRD, FE-SEM, N2 adsorption–desorption, 27Al MAS NMR and NH3-TPD.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Controlled synthesis of tunable nanoporous carbons for gas storage and
           supercapacitor application
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Kolleboyina Jayaramulu , Kasibhatta Kumara Ramanatha Datta , Konda Shiva , Aninda J. Bhattacharyya , Muthusamy Eswaramoorthy , Tapas Kumar Maji
      A simple methodology has been developed for the synthesis of functional nanoporous carbon (NPC) materials using a metal–organic framework (IRMOF-3) that can act as a template for external carbon precursor (viz. sucrose) and also a self-sacrificing carbon source. The resultant graphitic NPC samples (abbreviated as NPC-0, NPC-150, NPC-300, NPC-500 and NPC-1000 based on sucrose loading) obtained through loading different amounts of sucrose exhibit tunable textural parameters. Among these, NPC-300 shows very high surface area (BET≈3119m2/g, Langmuir≈4031m2/g) with a large pore volume of 1.93cm3/g. High degree of porosity coupled with polar surface functional groups, make NPC-300 remarkable candidate for the uptake of H2 (2.54wt% at 1bar, and 5.1wt% at 50bar, 77K) and CO2 (64wt% at 1bar, 195K and 16.9wt% at 30bar, 298K). As a working electrode in a supercapacitor cell, NPC-300 shows excellent reversible charge storage thus, demonstrating multifunctional usage of the carbon materials.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Transformation of analcime into IMF structure during the synthesis of IMF
           zeolite
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Martin Kubů , Jan Přech
      The transformation of analcime into the IMF structure during the crystallization of IMF zeolite is presented. IMF zeolite was found to show behavior similar to TUN zeolite, i.e. crystallization at the expense of an intermediate. Analcime which appeared first in the reaction mixture was further transformed into the IMF structure for aluminosilicate gels with the initial Si/Al ratio in the range of 15–20, i.e. under conditions being optimal for the synthesis of pure IMF phase and also even when seeding the final gel. The effect of synthesis conditions (Si/Al ratio, temperature, time) on the course of crystallization and properties of the high-silica IMF zeolite was investigated and compared with analcime (having the same Si/Al ratio) prepared from clear solutions not containing any organic template and using the same sources of silicon and aluminum as for the synthesis of IMF. The detailed characterization of prepared samples during crystallization is presented.
      Graphical abstract image Highlights

      PubDate: 2015-01-19T16:34:09Z
       
  • Hierarchical core–shell zeolite composite ZSM-5@SAPO-34 fabricated
           by using ZSM-5 as the nutrients for the growth of SAPO-34
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Jiajun Zheng , Guangshuai Wang , Meng Pan , Dalei Guo , Qiaoqiao Zhao , Biao Li , Ruifeng Li
      A series of zeolite composites with a hierarchical pore system were prepared by using ZSM-5 zeolite powder as the nutrients for the growth of SAPO-34. Factors controlling the formation of the aimed zeolite composite were investigated in details. The structural, crystalline, and textural properties of the zeolite composites, as well as the references ZSM-5, SAPO-34 and physical mixture composed of ZSM-5 and SAPO-34, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) analyses, intrusive mercury experiments, Fourier transform infrared spectroscopy (FTIR), temperature-programmed desorption of ammonia (NH3-TPD), and nitrogen adsorption/desorption techniques. The results display that the incompatibility of the core and shell layer with the different zeolite structure types, chemical compositions and crystallization conditions can be circumvented by using ZSM-5 zeolite cores as the nutrients for the growth of SAPO-34 zeolite in the shell; acidity properties and the ratios of SAPO-34/ZSM-5 in the composites can be adjusted; a hierarchical system with a mesopore centering at about 15nm and a macropore centering at about 150nm was introduced into the zeolite composite samples.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Mesoporous silica coatings with improved corrosion protection properties
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Emőke Albert , Nicoleta Cotolan , Norbert Nagy , György Sáfrán , Gabriella Szabó , Liana-Maria Mureşan , Zoltán Hórvölgyi
      Sub-micrometer thin, compact and mesoporous silica coatings were prepared on Zn substrates by sol–gel method, aiming the replacement of traditional chromates conversion coatings and pretreatments. The effect of layer thickness, porosity and the character of pore structure, number of thermal treatments, and various silylating agents were studied on the anti-corrosion behavior of the coatings, systematically and comparatively. The surface-, structural-, and optical properties of various silica thin films were characterized with different methods thoroughly. The corrosion resistance of the coatings was comparatively evaluated by open circuit potential measurements, Tafel interpretation of the polarization curves, and electrochemical impedance spectroscopy. Thicker films have better anti-corrosion property, as expected. More interestingly, we show that porous layers can have such a good corrosion resistance as compact films. This fact has special importance when impregnation with inhibitor would be applied. Furthermore, rendering the coatings hydrophobic improves the corrosion resistance of both porous and compact coatings significantly. The character of pore structure, the type of silylating agents, and the thermal treatment applied between two consecutive dippings do not affect notably the protective properties of the silica films. Furthermore, we demonstrate the difference in the accessibility of the pores in the case of ordered and disordered pore structure.
      Graphical abstract image Highlights

      PubDate: 2015-01-19T16:34:09Z
       
  • A facile synthesis of graphene-supported mesoporous TiO2 hybrid sheets
           with uniform coverage and controllable pore diameters
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Lifang He , Ning Du , Chundong Wang , Xianfeng Chen , Wenjun Zhang
      Mesoporous TiO2 has attracted extensive research interest due to its promising application in photocatalysis, but which is inevitably diminished by the electro-hole pair recombination. The incorporation of graphene into mesoporous TiO2 can improve the properties, there are however great challenges in realizing the full potential of graphene due to its poor dispersion in organic solvents and the hard nucleation of TiO2 on its surface. Herein, we present a novel and easy approach for the synthesis of two-dimensional sandwich-like graphene-supported mesoporous TiO2 hybrid sheets with tailored morphologies, uniform coverage and controllable pore diameters and surface areas, leading to improved photocatalytic performance in comparison with bare mesoporous TiO2 spheres.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Hexamethyleneimine and pivalonitrile as location probe molecules of Lewis
           acid sites on MWW-type zeolites
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Yuichi Matsunaga , Hiroshi Yamazaki , Hiroyuki Imai , Toshiyuki Yokoi , Takashi Tatsumi , Junko N. Kondo
      Locations of Lewis acid sites (LASs) on three MWW-type zeolites, the conventional Al-containing MWW zeolite (Al-MWW), acid-treated Al-containing MWW zeolite (Al-MWW-AT) and interlayer-expanded Al-containing MWW zeolite (Al-IEZ-MWW), were clarified by IR method using hexamethyleneimine (HMI), pivalonitrile (PN) and CO as probe molecules. No significant difference was found for Brønsted acid sites (BASs) in the strength and positions, while the locations of LASs were distinguished. LASs existed only on the external surfaces of Al-MWW, and in the expanded interlayer micropores (12-membered ring, 12-MR) of Al-IEZ-MWW. The simple acid treatment with nitric acid was found to generate LASs in the interlayer 10-MR micropores of Al-MWW-AT. The reactivity of the three zeolites depending on the positions of the active LASs was further confirmed in the Meerwein–Ponndorf–Verley (MPV) reduction of different ketones in size; 4-methylcyclohexanone and 2-butanone. Al-IEZ-MWW was superior for the reduction of 4-methylcyclohexanone over LASs in the interlayer 12-MR micropores, and Al-MWW-AT also showed fair reactivity for the reduction of smaller 2-butanone over LASs in the interlayer 10-MR micropores.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Influence of pore symmetries on the supercapacitive performance of
           mesoporous carbons co-templated by F127 and PDMS–PEO
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Yurong Liu , Jin Zhang
      In the present study, the mesoporous carbons (MPCs) with 2D hexagonal (p6m) and three-dimensional (3D) body-centered cubic (Im 3 ¯ m) symmetry were synthesized by using triblock copolymer PEO–PPO–PEO (F127) and diblock copolymer polydimethylsiloxane–poly(ethylene oxide) (PDMS–PEO) as co-templates. Common activating agent KOH was further utilized to improve the surface area and micropore volume of the MPCs. Their electrochemical performance as electrode materials for supercapacitors was investigated by cyclic voltammetry, galvanostatic charge–discharge tests and electrochemical impedance spectroscopy. It was found that the supercapacitive performance of 2D p6m mesoporous carbon was superior to that of 3D Im 3 ¯ m mesoporous carbon because 2D cylindrical mesopores facilitated the faster ion transfer along their smooth channels than within the isolated pores of 3D cubic mesopores. Compared to the pristine mesoporous carbons, the activated samples exhibited notable enhancements in specific capacitances because the micropores produced by KOH activation made the isolated pores interconnect to each other, thus providing more entrances for electrolyte diffusion and also shortening the diffusion distance. The activated sample with 2D p6m symmetry (A-2D-MPC) exhibited the highest specific capacitance of 226.3Fg−1 in 6M KOH at the current density of 1Ag−1.
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      PubDate: 2015-01-19T16:34:09Z
       
  • ZIF-8 membranes prepared at miscible and immiscible liquid–liquid
           interfaces
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Nobuo Hara , Miki Yoshimune , Hideyuki Negishi , Kenji Haraya , Shigeki Hara , Takeo Yamaguchi
      ZIF-8 membranes are currently attracting attention for the separation of propylene/propane based on the molecular sieve effect. We have recently reported the preparation of ZIF-8 membranes using the counter-diffusion method, which is advantageous in reducing defects in the selective layer. In the present study, ZIF-8 membranes were prepared at the interface of miscible and immiscible pairs of solvents such as water/methanol and water/1-octanol, respectively. ZIF-8 membranes prepared from the immiscible pair of water and 1-octanol showed a propylene permeance of 5.2×10−9 molm−2 s−1 Pa−1 and a propylene/propane permselectivity of 7.2 at 25°C. As for the ZIF-8 membrane prepared by the initial reaction using the immiscible pair of water/1-octanol and the successive reaction using the miscible pair of water/methanol mixture, the average propylene permeance and average propylene/propane permselectivity increased to 1.2×10−8 molm−2 s−1 Pa−1 and 20 at 25°C, respectively. The successive reactions in water/1-octanol and water/methanol mixtures successfully decreased the defects in the ZIF-8 selective layer, resulting in high propylene permeance and high permselectivity for propylene/propane. The structure and gas permeation properties were also thoroughly characterized.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Verified synthesis of pure silica CHA-type zeolite in fluoride media
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Manabu Miyamoto , Takenao Nakatani , Yuichi Fujioka , Katsunori Yogo
      Among the increasingly popular zeolites with eight-membered ring channels, CHA-type zeolites are considered to have great potential for various applications such as catalysis and separation. While CHA-type aluminosilicates with Si/Al ratios below 100 can be synthesized in both hydroxide and fluoride media, to date, pure silica CHA-type zeolites can only be prepared in a fluoride medium, with a low H2O/SiO2 of 3. Herein, we investigated the effect of various synthesis conditions on the formation of pure silica CHA-type zeolites. Single phase crystalline pure silica CHA was synthesized within a very narrow range of H2O/SiO2 ratio, and small deviations in the water content from this range led to the formation of STT-type zeolites. High N,N,N-trimethyl-1-adamant ammonium fluoride/SiO2 ratios allowed the formation of pure silica CHA, with no by-products, in the synthesis gel, with a high H2O/SiO2 ratio of 8. Additionally, synthesis conditions, in particular the H2O/SiO2 ratio, significantly influenced the specific surface and pore volume of CHA.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Fenton chemistry-based detemplation of an industrially relevant
           microcrystalline beta zeolite. Optimization and scaling-up studies
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): María Jesús Ortiz-Iniesta , Ignacio Melián-Cabrera
      A mild template removal of microcrystalline beta zeolite, based on Fenton chemistry, was optimized. Fenton detemplation was studied in terms of applicability conditions window, reaction rate and scale up. TGA and CHN elemental analysis were used to evaluate the detemplation effectiveness, while ICP, XRD, LPHR-Ar physisorption, and 27Al MAS NMR were applied to characterize the structure and texture of the resulting materials. The material properties were compared to calcination. By understanding the interplay of relevant parameters of the Fenton chemistry, the process can be optimized in order to make it industrially attractive for scale-up. The H2O2 utilization can be minimized down to 15mLH2O2/g (88°C, 30ppm Fe), implying a high solid concentration and low consumption of H2O2. When Fe concentration must be minimized, values as low as 5ppm Fe can be applied (88°C, 30mL H2O2/g), to achieve full detemplation. The reaction time to completeness can be reduced to 5h when combining a Fe-oxalate catalyst with UV radiation. The protocol was scaled up to 100times larger its original recipe. In terms of the material’s properties, the scaled material is structurally comparable to the calcined counterpart (comparable Si/Al and XRD patterns), while it displays benefits in terms of texture and Al-coordination, the latter with full preservation of the tetrahedral Al.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Changes of medium-range structure in the course of crystallization of
           mordenite from diatomite
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Miao Cui , Lin Wang , Yifu Zhang , Yu Wang , Changgong Meng
      Mordenite was synthesized from diatomite in a template-free system. The crystallization behavior and changes of medium-range structure during the crystallization were studied by X-ray diffraction, scanning electron micrograph, vibrational spectroscopy and high-energy X-ray diffraction. It is indicated that major 4-membered rings are formed at a stage later than that of 5-membered ring in the course of crystallization. Diatomite has also been demonstrated to consist of 5-membered rings and various rings lager than 5-membered ring. A formation pathway for mordenite from diatomite could be proposed that 5-membered rings formed initially are undergoing accommodation of 4-membered rings around them to form mordenite.
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      PubDate: 2015-01-19T16:34:09Z
       
  • Effect of post treatment on the local structure of hierarchical Beta
           prepared by desilication and the catalytic performance in
           Friedel–Crafts alkylation
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Yi Wang , Yinyong Sun , Christine Lancelot , Carole Lamonier , Jean-Charles Morin , Bertrand Revel , Laurent Delevoye , Alain Rives
      Desilication method has been developed to prepare hierarchical zeolites. However, the hierarchical Beta prepared by desilication generally exhibited much poorer catalytic activity than parent one in some acid-catalyzed reactions mainly due to the great loss of acidity. Here, we report that subsequent acid treatment after desilication can greatly recover the acidity of zeolite Beta. As a result, the hierarchical Beta with acid treatment exhibited enhanced catalytic performance in the benzylation of benzene or mesitylene with relatively large molecular size. Additionally, the local structural change in zeolite Beta before and after post treatment was deeply studied by the NMR technique. The results indicated that during the desilication partial tetrahedral coordination Al was transformed into the distorted tetrahedral and pentahedral coordination Al and subsequent acid treatment led to the increase of the proportion of tetrahedral coordination Al. Thus, the number of total Brönsted acid sites in zeolite Beta was decreased after the desilication and subsequent acid treatment may increase the number of total and accessible Brönsted acid sites. These results suggested that acid treatment is helpful for improving the catalytic performance of the desilicated Beta in some acid-catalytic reactions, especially toward large molecules.
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      PubDate: 2015-01-19T16:34:09Z
       
  • High activity ordered mesoporous carbon-based solid acid catalyst for the
           esterification of free fatty acids
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Minhua Zhang , Anxia Sun , Yonglu Meng , Lingtao Wang , Haoxi Jiang , Guiming Li
      Sulfonated mesoporous carbon catalysts were synthesized using a carbonization–sulfonation method and employed to the pre-esterification of free fatty acids contained in high acid value oil. Various synthesis parameters, such as composition of carbon precursor, carbonization and sulfonation temperature, were systematically investigated. The catalysts were characterized by N2 adsorption, small angle XRD, HRTEM, FT-IR and strong acid density analysis. The results indicated that they have a high surface area, uniform pore size, large mesopore volume, high acid density and good catalytic activity. Among them, MC600-S160 exhibited a highest activity and good stability for the esterification of FFA with methanol, the FFA conversion reached 94.6% after reaction for 3h.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • EMT-type zeolite nanocrystals synthesized from rice husk
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Eng-Poh Ng , Hussein Awala , Kok-Hou Tan , Farook Adam , Richard Retoux , Svetlana Mintova
      Nanosized EMT-type zeolite crystals with a diameter of 15nm are synthesized from a precursor suspension free of organic template using rice husk ashes (RHA) as a silica source. The crystallization process of the EMT-type zeolite is accomplished within 28h at 28°C. The fully crystalline EMT-type zeolite nanoparticles have equilateral hexagonal shape, Si/Al ratio of 1.28 and high crystalline yield of 75%.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Adsorption of casein onto some oxide minerals and electrokinetic
           properties of these particles
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Özkan Demirbaş , Mahir Alkan , Aygül Demirbaş
      In this study, the adsorption properties of casein onto some oxide minerals such as sepiolite, kaolinite and expanded and unexpanded perlites samples were studied as a function of concentrations of casein, sodium phosphate and NaCl, temperature and pH of the aqueous solutions. According to the experimental results, the adsorption of casein increases with temperature from 15 to 45°C and ionic strengths of the solutions over the range of 0.0 and 0.1molL−1. The adsorption decreased with increasing pH from 7.00 to 11.00 and the concentration of phosphate ions from 0.02 to 0.10molL−1. Maximum adsorption capacity values (qm ) showed dependence on pH. It was observed that qe–pH curves reached a maximum at around neutral pH value. Furthermore, the electrokinetic properties of casein-covered oxide particles were also investigated at similar conditions to those of the adsorption process. The nature of the adsorption process was investigated using Langmuir and Freundlich isotherm models.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Interconnected porous carbon with tunable pore size as a model substrate
           to confine LiFePO4 cathode material for energy storage
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Fei Cheng , Shuai Wang , Chu-Ying Wang , Wen-Cui Li
      LiFePO4/C composites with tunable particle size and loading content have been prepared using the porous carbon with large pore volume and controllable pore size as an interconnected conductive framework and rigid nano-confinement matrix. The large pore volume of carbon provides sufficient space for LiFePO4 hosting and the controllable pore size of carbon restricts the growth of LiFePO4 crystals to further improve the rate performance. When used as the cathode materials for lithium-ion batteries, they exhibit a stable and high reversible capacity of 161mAhg− 1 at 0.1C, 106mAhg− 1 at 20C and 50mAhg− 1 at 50C. The cell retains 94% of its initial capacity at 20C over 200 cycles with an ultrahigh specific power of 10,446Wkg− 1. The high rate performance and good cycle stability can be ascribed to the small nano-sized LiFePO4 confined in the nanopores of the carbon matrix with suitable loading content and good contact between LiFePO4 and the continuous conductive carbon framework, thus allowing fast lithium-ion diffusion and electrons transfer. This structure model may be valid for better understanding the rate performance and might be extended for fabrication of other high power electrode materials.
      Graphical abstract image Highlights

      PubDate: 2015-01-19T16:34:09Z
       
  • Dehydration of glycerol to acrolein using H-ZSM5 zeolite modified by
           alkali treatment with NaOH
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): H.P. Decolatti , B.O. Dalla Costa , C.A. Querini
      The dehydration of glycerol to acrolein has been studied using H-ZSM5 zeolite treated in alkaline medium in order to develop mesoporosity by desilication. Treatment of H-ZSM5 zeolite (Si/Al: 15) in NaOH solutions leads to mesoporosity development due to the preferential extraction of Si from the zeolite framework (desilication) without significant modification of the intrinsic zeolite properties. The samples were studied by powder X-ray diffraction (XRD), N2 adsorption, pyridine-temperature programmed desorption (Py-TPD) and FTIR of adsorbed pyridine. The coke deposits were analyzed by temperature programmed oxidation (TPO). The alkaline treatment conditions led to an increase in the mesopore surface area from 254m2 g−1 for the calcined zeolite to 325m2 g−1 for the alkaline-treated material, while the micropore volume was only slightly decreased (from 0.136 to 0.130mlg−1). Besides substantial mesoporosity development, the zeolite maintained Brønsted acidic properties, which are highly attractive in order to promote acid-catalyzed reactions like glycerol dehydration. Catalytic testing of the modified solids showed an improved performance in dehydration of glycerol to acrolein, due to the unique interplay between improved physical transport in the shortened micropores and the preserved high density of acid sites. The catalyst stability was improved upon desilication due to an increase in coke tolerance. A treatment of both solids in air at 773K led to a partial regeneration of acid sites for glycerol dehydration.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • One-pot synthesis of iron oxide mesoporous silica core/shell
           nanocomposites
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Paul S. Mueller , Connor P. Parker , Sarah C. Larsen
      Iron oxide/mesoporous silica core/shell nanocomposites are an increasingly important class of materials with a wide range of applications. In the pursuit of more efficient synthetic techniques, this paper presents a methodology for the one-pot synthesis of discrete iron oxide/mesoporous silica core/shell nanocomposites with dimensions of less than 100nm starting with iron chloride precursors. Reaction conditions including secondary organic amine identity and concentration, base source, surfactant identity and silica concentration were varied in order to optimize the synthesis. By changing these conditions, the factors that control particle size, iron loading, and aggregation were identified.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • High-pressure behavior and crystal–fluid interaction under extreme
           conditions in paulingite [PAU-topology]
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): G. Diego Gatta , Katharina S. Scheidl , Thomas Pippinger , Roman Skála , Yongjae Lee , Ronald Miletich
      The compressional behavior and the P-induced crystal–fluid interaction of a natural paulingite-K have been explored on the basis of in-situ single-crystal and powder X-ray diffraction, and in-situ single-crystal Raman spectroscopy with a diamond anvil cell and a series of diverse pressure-transmitting fluids (i.e., silicone-oil, methanol:ethanol=4:1, methanol:ethanol:water=16:3:1). No evidence of any phase transition was observed within the P-range investigated, independent on the used P-fluids. The compressional behavior of paulingite is significantly different in response to the different nature of the P-fluids. A drastically lower compressibility is observed when the zeolite is compressed in methanol:ethanol or, even more noticeably, in methanol:ethanol:water mix. We ascribe this phenomenon to the different crystal–fluid interaction at high pressure: (1) silicone-oil is a “non-penetrating” P-medium, because of its polymeric nature, whereas (2) methanol–ethanol and water are “penetrating” P-fluids. The P-induced penetration processes appear to be completely reversible on the basis of the X-ray diffraction data alone. The Raman spectra collected after the high-pressure experiments show, unambiguously, that a residual fraction of methanol (and/or ethanol and probably even extra H2O) still resides in the zeolitic sub-nanocavities; such molecules are spontaneously released after a few days at atmospheric pressure. The actual compressibility of paulingite-K is that obtained by the compression experiment in silicone-oil, with an isothermal bulk modulus K 0 = β 0 −1 =18.0(1.1)GPa. Paulingite appears to be one of the softest zeolite ever found.
      Graphical abstract image Highlights

      PubDate: 2015-01-19T16:34:09Z
       
  • Fluorocarbon functionalized SAPO-34 zeolite incorporated in asymmetric
           mixed matrix membranes for carbon dioxide separation in wet gases
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): M.U.M. Junaidi , C.P. Leo , A.L. Ahmad , N.A. Ahmad
      In order to sustain the performance of mixed matrix membrane (MMM) in the separation of wet gases such as biogas, water-resistant MMMs were fabricated by incorporating fluorocarbon functionalized SAPO-34 zeolite into polysulfone (PSf). 1H,1H,2H,2H-perflourodecyltriethoxysilane (HFDS) was used to convert the hydrophilic SAPO-34 zeolite into hydrophobic SAPO-34 zeolite to avoid competitive adsorption of moisture. After dispersing the modified filler in polymer solution, asymmetric MMMs were fabricated via dry–wet phase inversion. N2 adsorption–desorption test and thermal gravimetric analysis indicated that fluorocarbon modification generated minimum impact on the surface area and CO2 adsorption capability of SAPO-34 zeolite. The water contact angle on SAPO zeolite increased from 33° to 130° after modification, while the membrane hydrophobicity was enhanced about 17.64%. The MMM with 10wt.% of modified SAPO-34 zeolite (PSf-10/HFDS 1.0) exhibited good adhesion between filler and polymer phases, minimizing defect such as interface voids. PSf-10/HFDS 1.0 MMM also showed great enhancement in ideal gas separation (ideal selectivity CO2/CH4 of 38.9 with CO2 permeance of 278GPU) compared to the neat PSf membrane and MMMs with unmodified SAPO-34 zeolite. In addition, PSf-10/HFDS 1.0 MMM showed actual gas selectivity at wet condition which is similar to its dry mixed-gas selectivity (2% reduction only). The mixed-gas separation performance for PSf-10/HFDS 1.0 MMM was even sustained in both dry and wet conditions during long-hour test. Compared to the dry mixed-gas results, MMM incorporated with 10wt.% of unmodified SAPO-34 (PSf-10) suffered more than 90% reduction in separation performance during wet mixed-gas test.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Porous poly(3,4-ethylenedioxythiophene) nanoarray used for flexible
           supercapacitor
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Yibing Xie , Hongxiu Du , Chi Xia
      Porous poly(3,4-ethylenedioxythiophene) (PEDOT) nanoarray used for flexible supercapacitor has been prepared to investigate its electrochemical capacitance performance. Well-aligned titania (TiO2) and titanium nitride (TiN) nanotube array was fabricated by an anodization, crystallization, nitridation processes. PEDOT-TiO2 and PEDOT-TiN nanoarray hybrid was fabricated by coating PEDOT on nanotube walls of TiO2 and TiN through a pulse voltammetry electrodeposition process. PEDOT nanopore array was fabricated through HF corrosion of TiN from PEDOT-TiN. The morphology and microstructure of PEDOT-TiO2, PEDOT-TiN and PEDOT were characterized by scanning electron microscopy and Raman spectroscopy. The electrochemical capacitance was investigated by cyclic voltammetry and galvanostatic charge–discharge measurements. PEDOT-TiO2 and PEDOT-TiN showed heterogeneous coaxial nanotube structure. PEDOT exhibited free-standing nanopore array structure. The specific capacitance of PEDOT-TiN nanoarray hybrid was determined to be 393.1Fg−1 at a current density of 1.0mAcm−2, presenting much higher capacitance than PEDOT-TiO2 nanoarray hybrid (128.7Fg−1) and PEDOT nanopore array (109.3Fg−1). All-solid-state flexible supercapacitor was constructed using supple electrode of PEDOT-TiN nanoarray hybrid and polyvinyl alcohol gel electrolyte of sulphuric acid. The volume specific capacitance, energy and power density were determined to be 4.08Fcm−3, 2.26mWhcm−3 and 250mWcm−3 at a high output voltage of 2.0V and a current density of 10mAcm−2. PEDOT-TiN nanoarray hybrid exhibited the effective energy storage in flexible supercapacitor application.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Synthesis of amino-functionalized MCM-48 silica via direct co-condensation
           at room temperature
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Griselda Castruita-de León , Yibran Argenis Perera-Mercado , Luis Alfonso García-Cerda , Jesús Alfonso Mercado-Silva , Héctor Iván Meléndez-Ortiz , Yeraldin Olivares-Maldonado , Lorena Alvarez-Contreras
      Amino-functionalized MCM-48 silicas with highly ordered porous structure have been successfully synthesized through a co-condensation method carried out at room temperature under basic conditions. The influence of experimental conditions on the structural, morphological and textural properties of materials has been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and specific surface areas, pore volumes and pore sizes distribution were calculated from N2 adsorption/desorption isotherms. Based on X-ray diffraction patterns, the amino-functionalized silica samples synthesized with the optimal reaction parameters exhibited intense and well-defined reflections typical of cubic MCM-48 structure. Besides, the pore ordering of MCM-48 silica network was resistant to the extraction conditions of surfactant. The presence of the organosilane introduced into the silica network as functionalizing agent was identified by infrared spectroscopy and the amino groups content was estimated by a fluorometric method with fluorescamine.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Production of epoxy spherical mesoporous as a spherical membrane separator
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Bee Ing Sea , Du Ngoc Uy Lan , Hui Lin Ong
      Epoxy spherical membrane (ESM) is a porous epoxy material, a combination of micro-spherical particles. The spherical membrane, built from the space formed among the particles is applied for filtering and separation purposes. ESM was obtained after curing the emulsion of the epoxy mixture (epoxy, polyamide and calcium carbonate (CaCO3)) and water, which was prepared based on the water in oil in water (W/O/W) technique by using a high speed homogenizer. It was found that an increase in CaCO3 content produced smaller spherical epoxy particles and a higher porosity ESM. Therefore, a reduction in compression strength was induced; however, the compression modulus was increased. An ESM column with polypropylene (PP) tubes was applied as the separator column. Using the ESM column, carbon black N330 was successfully separated from the water. They were located at the top of the ESM column and trapped among the epoxy micron particles. ESM-25 possessed the highest flow rate of the water medium, while ESM-50 exhibited the highest weight of carbon black at the top of the membrane and the lowest weight of carbon trapped in the column. The oil–water separation function of ESM was observed using crude oil–water and palm oil–water solutions. Oils travelled slower through the ESM column in comparison to water, so the separation occurred; hence pure water was obtained first followed by the oils. It was found that ESM-25 exhibited the best oil flow rate for palm oil separation, while ESM-50 exhibited the best crude oil separation.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Preparation and photocatalytic activity of hierarchically 3D ordered
           macro/mesoporous titania inverse opal films
    • Abstract: Publication date: 1 March 2015
      Source:Microporous and Mesoporous Materials, Volume 204
      Author(s): Wenfang Liu , Aijun Wang , Junjie Tang , Sheng-Li Chen , Guimei Yuan , Kun Zhao , Changxi Li , Xuecheng Liu
      Hierarchically ordered macro/mesoporous titania inverse opal (TiO2-IO) films were prepared using a polyethyl glycol (PEG)-associated sol–gel method. Macroporous templates were obtained using the self-assembly of monodispersed polystyrene (PS) microspheres into opal structures, which were subsequently infiltrated with titanium alkoxide precursors containing PEG 2000 as the mesopore directing agent. After the PS and PEG 2000 were removed by calcination, TiO2-IO hierarchical structures with macro/mesopores were formed. SEM and TEM images show that the novel films were of 3D ordered macroporous structure, composed of titanium dioxide frameworks and several hundred nanometers spherical air voids arranged in an fcc close-packing array, and the ordered framework possessed numerous mesopores. The hierarchically ordered macro/mesoporous TiO2-IO films prepared displayed enhanced photocatalytic activity in the decolorization of rhodamine B (RhB) in a solid state photocatalytic process. The PEG 2000 content has a significant influence on the photocatalytic activity and the optimal PEG 2000 content was determined. The sample prepared with 2.1wt.% PEG 2000 showed the highest photocatalytic activity with a rate constant (k)=0.1346min−1, which is a six fold increase on that found with TiO2-IO in the absence of PEG 2000 (k =0.0225min−1). However, an excessive amount of PEG 2000 results in the destruction of the macroporous structure and a loss of photocatalytic activity. The enhanced photocatalytic activity was attributed to the incorporation of mesopores into the macroporous skeleton via decomposition of PEG 2000 in the film. This increases the accessible surface area of the film, improves mass transport and reduces the length of the mesopore channels.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Effects of La2O3, CeO2 and LaPO4 introduction on vanadium tolerance of USY
           zeolites
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Xiaohui Du , Haitao Zhang , Gengzhen Cao , Lin Wang , Chenxi Zhang , Xionghou Gao
      Rare earth compounds were employed as vanadium traps in USY zeolite. USY zeolites containing La2O3, CeO2 and LaPO4 were prepared by precipitation method and characterized by means of BET, TEM, XPS, XRD and Rietveld refinement. The results indicated that the rare earth oxides were highly dispersed in zeolites and some of rare earth cations moved to zeolite cages, which improved the hydrothermal stability and catalytic activity of zeolites. In LaPO-USY zeolite, rare earth specie, as LaPO4, was distributed on the zeolite surface and did not affect the properties of catalyst. With rare earth elements at the same contents, the vanadium resistances of zeolites followed a descending order of LaPO-USY>Ce-USY>La-USY>USY. The significant differences between activation energies of zeolite destruction can be attributed to various vanadium tolerances.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Monolithic metal-fiber@HZSM-5 core–shell catalysts for
           methanol-to-propylene
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Ming Wen , Xiangyu Wang , Lupeng Han , Jia Ding , Ying Sun , Ye Liu , Yong Lu
      Monolithic metal-fiber@HZSM-5 core–shell catalysts have been developed by direct growth of zeolite crystals on a macroscopic 3D network of sinter-locked metal microfibers. This approach provides a combination of excellent thermal conductivity, hierarchical porous structure from micro- to macro-size, and unique form factor. The metal-fiber@HZSM-5 catalysts, with high HZSM-5 loadings (e.g., 27–30wt%) and excellent core–shell robustness, deliver dramatic selectivity and life-time improvement in the methanol-to-olefin process. Such unprecedented performance is due to propagation of the olefin methylation/cracking cycle over the aromatic-based cycle in the methanol-to-hydrocarbon catalysis. Using a feed of 30vol% methanol in N2, for example, at 480°C high propylene selectivity of ∼46% can be obtainable with a total C2–C4 olefin selectivity of ∼70%, being much higher than that (∼37%, C2–C4 olefin selectivity of ∼64%) for the corresponding zeolite powder. The core–shell catalyst is stable at least for 210h, almost 3-fold longer than the life-time of 60h for the powdered HZSM-5 catalysts, because the coking rate is obviously suppressed in association with the propagated olefin-based cycle.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
  • Optimization of the combined adsorption/photo-Fenton method for the
           simultaneous removal of phenol and paracetamol in a binary system
    • Abstract: Publication date: April 2015
      Source:Microporous and Mesoporous Materials, Volume 206
      Author(s): Mohammad Irani , Leila Roshanfekr Rad , Hamed Pourahmad , Ismaeil Haririan
      The coupling of adsorption and photo-Fenton processes has been studied for the simultaneous removal of phenol and paracetamol from aqueous systems. Photo-Fenton process exhibited the complete elimination of phenol and paracetamol during 1h. For mineralization of contact time, the adsorption process was combined to the photo-Fenton process. The both NaX nanozeolites and cobalt ferrite nanoparticles were synthesized by microwave heating method and were used through the adsorption and photo-Fenton processes, respectively. The nanoparticles were characterized by XRD and SEM analysis. The Box–Behnken design was applied to evaluate the effect of key parameters including pH (3–4), phenol initial concentration (20–100mgL−1), paracetamol initial concentration (20–100mgL−1) and NaX to cobalt ferrite nanoparticles ratio (0.5–1.5) on the simultaneous removal of phenol and paracetamol at contact time of 30min. By optimization of parameters, the removal percentages of phenol and paracetamol were found to be 99.95% and 99.80%, respectively. The results demonstrate that the coupling of adsorption and photo-Fenton processes is an alternative method to eliminate the phenolic compounds from wastewaters.
      Graphical abstract image

      PubDate: 2015-01-19T16:34:09Z
       
 
 
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