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PHYSICS (538 journals)            First | 1 2 3 4 5 6 | Last

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: 9)
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: 14)
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: 11)
Lasers in Surgery and Medicine     Hybrid Journal  
Latvian Journal of Physics and Technical Sciences     Open Access  
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 9)
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: 1)
MAPAN     Hybrid Journal  
Mass Spectrometry Reviews     Hybrid Journal   (Followers: 17)
Matéria (Rio de Janeiro)     Open Access   (Followers: 1)
Materials & Design     Hybrid Journal   (Followers: 21)
Materials at High Temperatures     Full-text available via subscription   (Followers: 4)
Materials Chemistry and Physics     Full-text available via subscription   (Followers: 11)
Materials Research     Open Access   (Followers: 7)
Materials Research Bulletin     Hybrid Journal   (Followers: 16)
Materials Science     Hybrid Journal   (Followers: 7)
Materials Science and Engineering: A     Hybrid Journal   (Followers: 31)
Materials Science and Engineering: B     Hybrid Journal   (Followers: 15)
Materials Science and Engineering: C     Hybrid Journal   (Followers: 14)
Materials Science and Engineering: R: Reports     Hybrid Journal   (Followers: 10)
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: 1)
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  
NANO     Hybrid Journal   (Followers: 6)
Nano Letters     Full-text available via subscription   (Followers: 42)
Nano Reviews     Open Access   (Followers: 15)
Nanoscale and Microscale Thermophysical Engineering     Hybrid Journal   (Followers: 3)
Nanoscale Research Letters     Open Access   (Followers: 4)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 13)
Natural Science     Open Access   (Followers: 9)
Nature Communications     Hybrid Journal   (Followers: 40)
Nature Materials     Full-text available via subscription   (Followers: 40)
Nature Physics     Full-text available via subscription   (Followers: 23)
NDT & E International     Hybrid Journal   (Followers: 11)
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: 4)
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: 3)
Organic Electronics     Hybrid Journal   (Followers: 3)
PAJ: A Journal of Performance and Art     Hybrid Journal   (Followers: 11)
Particle Physics Insights     Open Access   (Followers: 2)
Particuology     Hybrid Journal  
Pattern Recognition in Physics     Open Access   (Followers: 1)
Pergamon Materials Series     Full-text available via subscription  
Phase Transitions and Critical Phenomena     Full-text available via subscription   (Followers: 1)
Philosophical Magazine     Hybrid Journal   (Followers: 2)
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences     Full-text available via subscription   (Followers: 5)
Philosophy and Foundations of Physics     Full-text available via subscription  

  First | 1 2 3 4 5 6 | Last

Journal Cover Microporous and Mesoporous Materials
   Journal TOC RSS feeds Export to Zotero [5 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1387-1811
     Published by Elsevier Homepage  [2566 journals]   [SJR: 1.306]   [H-I: 93]
  • Tuning properties of silicalite-1 for enhanced ethanol/water pervaporation
           separation in its PDMS hybrid membrane
    • Abstract: Publication date: 1 January 2015
      Source:Microporous and Mesoporous Materials, Volume 201
      Author(s): Naixin Wang , Jida Liu , Jie Li , Jing Gao , Shulan Ji , Jian-Rong Li
      The silicalite-1/PDMS hybrid membranes have been widely studied in alcohol perm-selective pervaporation separations. However, the poor compatibility between silicalite-1 particles and PDMS has already rebated the separation performance of these hybrid membranes. In this paper, two approaches were investigated to improve/tune the compatibility of the silicalite-1 particles and PDMS matrix. Firstly, silicalite-1 crystal particles with different sizes were synthesized. The effects of the particle size on the compatibility between silicalite-1 and PDMS were investigated. It was found that smaller silicalite-1 crystals (about 100nm) have a better compatibility with PDMS matrix, thereby an enhanced separation performance of their hybrid membranes. Subsequently, the surface of silicalite-1 particles were modified through three kinds of silane coupling agents with different functional groups, which was confirmed to be feasible in increasing the compatibility with PDMS. In ethanol/water pervaporation separation, a higher selectivity was achieved in the PDMS hybrid membrane with TMDS-modified small silicalite-1 crystals. Moreover, silicalite-1 crystals provide many separate channels, so that the separation performance of the hybrid membrane has dramatically increased.
      Graphical abstract image

      PubDate: 2014-09-25T09:06:29Z
       
  • The influence of layered double hydroxide composition on the morphology,
           porosity and capacitive properties of nitrogen-doped carbon materials
           prepared via chemical vapor deposition
    • Abstract: Publication date: 1 January 2015
      Source:Microporous and Mesoporous Materials, Volume 201
      Author(s): Aleksandra Pacuła , Paweł Nowak , Wacław Makowski , Robert P. Socha
      Porous N-doped carbon materials of various morphologies are prepared via chemical vapor deposition (CVD) at 700°C using acetonitrile as carbon and nitrogen source and MgAl, MgCoAl, CoAl layered double hydroxides (LDHs) as template and catalyst precursors. The physicochemical properties of the carbon materials are characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, thermogravimetric analysis, elemental analysis, nitrogen sorption and n-nonane thermodesorption, whereas their electrochemical performance is evaluated in 6M KOH by means of cyclic voltammetry, galvanostatic charging/discharging and electrochemical impedance spectroscopy. The choice of LDHs strongly affects the grain morphology and micropore/mesopore contribution in the synthesized carbon materials, which determines their capacitive performance. The application of Co-free LDHs leads to the carbon material consisting of irregular aggregates of plate-like particles highly doped with nitrogen (9.7wt%) and having high specific surface area (863m2 g−1) and high capacitance (130Fg−1). On the other hand, the use of Co-containing LDHs results in the carbon materials predominantly made of carbon nanotubes (grown on metallic Co nanoparticles) less doped with nitrogen (2.4–3.1wt%) and having lower specific surface area (193–225m2 g−1) and lower capacitance (15–30Fg−1).
      Graphical abstract image Highlights

      PubDate: 2014-09-21T08:57:11Z
       
  • N-enriched ACF from coal-based pitch blended with urea-based resin for CO2
           capture
    • Abstract: Publication date: 1 January 2015
      Source:Microporous and Mesoporous Materials, Volume 201
      Author(s): Noel Díez , Patricia Álvarez , Marcos Granda , Clara Blanco , Ricardo Santamaría , Rosa Menéndez
      N-enriched activated carbon fibers were successfully prepared from a coal derived pitch blended with urea–formaldehyde resin. The mixture was melt-spun, stabilized, carbonized and activated with KOH, giving rise to microporous carbon fibers with high nitrogen content (up to 2.2%). Nitrogen functional groups were mostly identified as quaternary N, and the content in this nitrogen group decreased with the degree of activation. N-enriched fibers activated under mild conditions (KOH/fiber=5/1) showed the highest CO2 uptake (3.4mmol CO2 g−1 at 25°C and 1atm). Due to their high alkalinity, the N-enriched fibers showed high CO2 adsorption rates and good selectivities for CO2/N2 and CO2/CH4 separation. After saturation with CO2, the fibers could be easily regenerated and maintained their performance over several adsorption–desorption cycles.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Mesoporous silica SBA-15 functionalized by nickel–phosphonic units:
           Raman and magnetic analysis
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Łukasz Laskowski , Magdalena Laskowska , Maria Bałanda , Magalena Fitta , Jadwiga Kwiatkowska , Kazimierz Dziliński , Agnieszka Karczmarska
      In the present work we present mesoporous silica SBA-15 containing propyl-nickel phosphonate study towards confirmation of synthesis procedure correctness. The structure of mesoporous sample was tested by TEM microscopy, N2 sorption tests and X-ray scattering. To probe bounding between nickel atoms and phosphonic units the Raman spectroscopy was carried out. As a support of Raman scattering, the theoretical calculations were made based on density functional theory, with the B3LYP method. By comparison of the calculated vibrational spectra of the molecule with experimental results, distribution of the active units inside silica matrix has been determined. Magnetic measurements were carried out to find nickel ions concentration inside the mesoporous matrix, and also to determine nickel ions environment. Both magnetic and Raman study confirm the efficiency of the synthesis and corroborate the homogenous distribution of nickel–phosphonate active units in silica matrix.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Synthesis and supercapacitive performance of hierarchically porous
           graphitic carbon monoliths containing cobalt nanoparticles
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Yurong Liu , Baoping Lin , Dan Li , Tong Xu , Xueqin Zhang , Ying Sun , Hong Yang
      The hierarchically porous graphitic carbon monoliths containing cobalt nanoparticles (HPGCM-Co) have been successfully fabricated through multi-component co-assembly in polyurethane (PU) foam scaffold associated with a direct carbonization process from triblock copolymer F127, phenolic resol and Co(NO3)2·6H2O. In situ generated Co nanoparticles during the carbonization process act as catalysts for graphitization of carbon materials at relatively low carbonization temperatures (<1000°C). The obtained graphitic monolithic materials exhibit large macropores (100–450μm) and mesopores (5.1nm), high surface area (747m2 g−1) and pore volume (0.60cm3 g−1). Their supercapacitive performances have also been systematically studied. The galvanostatic charge–discharge results indicate that the specific capacitance of HPGCM-Co (231.6Fg−1) is 42% higher than that of cobalt-free hierarchically porous carbon monolith (HPCM) at current density of 1Ag−1 in 6M KOH aqueous solution, revealing a promising application in supercapacitors. The excellent supercapacitive performance of HPGCM-Co is attributed to its unique hierarchical porous structure and high graphitization degree.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Synthesis of ordered mesoporous iron manganese bimetal oxides for arsenic
           removal from aqueous solutions
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Zhipan Wen , Yalei Zhang , Chaomeng Dai , Bo Chen , Sujin Guo , Hong Yu , Deli Wu
      A novel ordered mesoporous iron manganese bimetal oxides (OMIM) was synthesized via the hard template approach. The obtained OMIM sample showed excellent performance for the arsenic removal due to its large surface area and pore volume. pH affected the removal efficiency of As(III) and As(V) significantly, and the highest removal occurred in acidic solutions for both arsenic species. The adsorption isotherms were well-described by Freundlich model, and the calculated adsorption capacities of As(III) and As(V) were 67.89 and 93.54mg/g, respectively. The adsorption kinetics fitted a pseudo-second order model, and intra-particle diffusion was not the only rate-limiting step in the adsorption process. Samples were characterized using SEM-EDS, TEM, XRD and XPS, and the redox states and yields of the arsenic species in aqueous solutions after the reaction of As(III)/As(V) with OMIM were also investigated by HPLC-ICP-MS. The results showed that the changed valence of Mn in OMIM favored As(III) removal and the mechanisms removal of both As(III) and As(V) were complex. In addition, to remove As(III) in aqueous solutions, OMIM plays a dual function as an efficient oxidant of As(III) due to its MnO2 content and subsequently as an excellent adsorbent for As(V).
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • A hierarchical porous carbon – Mn+[FAU] (Mn+=Ni2+ or Cu2+)
           adsorbent: Synthesis, characterization and adsorption of salicylic acid
           from water
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Karen M. González-Ramos , Bethzaely Fernández-Reyes , Félix R. Román , Arturo J. Hernández-Maldonado
      This work presents the preparation and characterization of a hierarchical porous carbon – Mn +[FAU] or Mn +-CFAU (Mn + =Ni2+ or Cu2+; FAU=Y zeolite) adsorbent as a potential platform to develop processes for the removal of contaminants of emerging concern (CECs) from water. The impetus for this contribution is the possibility of combining the hydrophobic nature of activated carbons with the unique adsorbent–adsorbate interactions provided by a transition metal based zeolite. A quasi-ordered (CFAU) composite was hydrothermally synthesized and subsequently decorated with extraframework transition metal centers (Ni2+ or Cu2+). The resulting CFAU variants were fully characterized using XRD, XPS, ICP-MS, TGA, zeta potential and nitrogen adsorption to determine chemical, structural and textural properties. Furthermore, these properties were used to assess the performance of the CFAU variants during salicylic acid (a CEC with high occurrence) equilibrium adsorption tests performed at 25°C and pH in the 7–8 range. In terms of performance, the salicylic acid equilibrium overall adsorption capacities increased as follows: FAU<Activated Carbon<CFAU<Ni2+-CFAU<<Cu2+-CFAU. Both transition metal-based composite adsorbents excelled at removing the acid even at concentrations near the 20ppb levels. Cu2+-CFAU was capable of adsorbing one salicylic acid molecule per zeolite unit cell at the maximum equilibrium loading observed. Thermal treatment tests suggest that spent Mn +-CFAU composites could be regenerated via elimination of the adsorbate in an inert environment without affecting the adsorbent structure.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Adsorption and co-adsorption of NO and water on LaCu-ZSM5
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): M. Tortorelli , G. Landi , L. Lisi , G. Russo
      The effect of water on NO adsorption on LaCu-ZSM5 has been studied by in-situ FTIR at 50°C identifying for which copper sites NO adsorption competes with water. The relative thermal stability of NO and H2O ad-species have been also determined by increasing the sample temperature from 50 to 400°C. Water was removed from zeolite at temperature lower than that necessary to desorb NO, as both bridged and chelating nitrates, from copper sites. A quantitative analysis of the adsorption of NO on the zeolite previously contacted with water was made by carrying out adsorption tests at temperatures far from those activating any DeNOx reaction in a lab-scale PFR reactor. The variation of the amount of adsorbed NO with the temperature of H2O desorption has been evaluated increasing the desorption temperature from 125 to 500°C after zeolite saturation with water at 125°C. The total recovery of the amount of NO adsorbed on the dry zeolite demonstrated the reversibility of water deactivation.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Adsorptive characterization of porous solids: Error analysis guides the
           way
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Martijn F. De Lange , Thijs J.H. Vlugt , Jorge Gascon , Freek Kapteijn
      Adsorptive characterization using nitrogen at 77K is one of the most widely used techniques to assess textural properties of porous solids, such as pore volume, specific surface area and pore size distributions. Based on a thorough error analysis the influence of experimental uncertainties on the accuracy of volumetric nitrogen adsorption isotherms and derived properties using the most popular methods is analyzed in detail, comprising the pore volume and specific surface area determined using the method posed by Brunauer, Emmet and Teller (BET) and the pore size distribution according to the method developed by Barrett, Joyner and Halenda (BJH). Based on series of isotherms measurements with different sorbents (MOFs, zeolite, activated carbon and alumina) and on examples from literature (MIL-101), the extensive error analysis shows that these methods may yield highly inaccurate or even statistically irrelevant (BJH) results. To improve the meaningfulness of derived properties and to minimize statistical uncertainties, practical recommendations and guidelines are proposed for experimental operation variables and data analysis.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • n-Heptane isomerization on a new kind of micro/mesoporous catalyst: Pt
           supported on HZSM-5/HMS
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): N. Parsafard , M.H. Peyrovi , M. Rashidzadeh
      Pt loaded on a series of ZSM-5/HMS composites with different H-zeolite amounts has been prepared and used as a solid acid catalyst for the catalytic isomerization of n-heptane. The structure characterization, acid distribution and morphology of the Pt catalysts supported on these composite materials were characterized by XRD, XRF, NH3-TPD, SEM, FTIR, Py-IR, H2 chemisorption, nitrogen sorption and TGA (for investigating the coke deposition) techniques. Compared with HMS and HZSM-5, these new composite materials have good ability for n-heptane isomerization. The results show that these micro/mesoporous catalysts have both properties of mesoporous HMS and microporous HZSM-5. The best i-C7 selectivity (35.8%) was observed for Pt/ZSM-5(30)-HMS at T =200°C. These new composite catalysts prove the catalytic stability at the reaction time, which results in their thicker pore-wall and appropriate acidity.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Tailoring porosity and dimensionality of Co3O4 nanophase using channel
           interconnectivity control by steaming of nanocasting SBA-15
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Xiao-Jing Ma , Ye-Jun Yu , Jun-Ling Xing , Tai-Qun Yang , Koon Fung Lam , Qing-Song Xue , Belén Albela , Laurent Bonneviot , Kun Zhang
      Two-dimensional hexagonal arrays of interconnected Co3O4 nano-rods or disconnected mono-dimensional Co3O4 nano-rods were nano-cast fabricated using SBA-15 as hard template with or without intra-wall microporosity, respectively. A clean, efficient and facile high temperature steam post-treatment is proposed to control the microporosity and the interconnectivity of the nanocasted oxide phase. Characterization by small-angle X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) suggests that the selective removal of micropores is resulted from hydrothermal restructuring within the pore wall of calcined SBA-15 followed by a sequential process, including hydrolysis and re-condensation of internal surface siloxane bonds and dissolution–migration–deposition of amorphous debris external onto the SBA-15 under the atmosphere of pure water vapor.
      Graphical abstract image Highlights

      PubDate: 2014-09-21T08:57:11Z
       
  • Atom transfer radical polymerization of diverse functional SBA-15 for
           selective separation of proteins
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Xiaoyan Liu , Xuezhao Shi , Hongmei Wang , Haixia Zhang
      Poor detection of low-abundant proteins is a common problem in most current protein identification schemes. This is attributed partially to the existence of high-abundant protein. Therefore, selective removal of specific proteins prior to analysis is in great demand. In response these needs, we previously described two kinds of ion exchange groups functionalized SBA-15 synthesized by direct silylanization reaction. Herein, we designed and synthesized strong anion, cation and zwitterion functionalized SBA-15 via atom transfer radical polymerization (ATRP). The previous and current materials were characterized and theirs adsorption abilities for some model proteins (bovine serum albumin (BSA), hemoglobin (Hb), myoglobin (Mb) and lysozyme (Lys)) were evaluated. The results demonstrated that different functionalized SBA-15 is capable to selective removal of certain proteins in protein mixture. It also indicated that this sample preparation technique could be potentially applied to reduce the complexity on protein identification for biological samples with a wide dynamic range.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Effects of adding alcohols on ZSM-12 synthesis
    • Abstract: Publication date: 1 January 2015
      Source:Microporous and Mesoporous Materials, Volume 201
      Author(s): Sinthuran Jegatheeswaran , Chin-Min Cheng , Chil-Hung Cheng
      This work systematically studies on adding alcohols to alter the crystal growth behavior of ZSM-12, using 1-propanol (1P), 2-propanol (2P), ethylene glycol (EG), 1,3-propanediol (PD), 1,6-hexanediol (HD), diethylene glycol (DEG), triethylene glycol (TEG), and tetraethylene glycol (TTEG) as co-solvents. The effects of co-solvent content, temperature, and excess mineralizer content were studied as well. Except 2P, all other co-solvents are observed to tune the crystal morphology into a discrete round-shape. Except DEG and TTEG, all other co-solvents promote the crystallization rate of MTW phase, verified by larger zeolite crystal size in SEM images. The observation is corroborated with the formation of cristobalite, possibly via Ostwald ripening mechanism. The finding enlightens us using a lower synthesis temperature to attain high purity MTW phase, with an adequate amount of co-solvents. It is noteworthy that using HD as co-solvent facilitate the anisotropic growth of MTW crystals along the b-axis (2θ of 8.5°), possibly due to the effect of co-solvent’s hydrophobicity as well as the backbone length. The blue shift of symmetric and asymmetric Si-O vibration modes in FTIR spectra implies that TEG and HD are incorporated within the ZSM-12 pore structure. This work provides potential synthetic route to form anisotropic ZSM-12 membranes with preferred orientation.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Acid properties and catalysis of USY zeolite with different
           extra-framework aluminum concentration
    • Abstract: Publication date: 1 January 2015
      Source:Microporous and Mesoporous Materials, Volume 201
      Author(s): Xin Pu , Nai-wang Liu , Li Shi
      USY zeolite was treated by the citric acid. The properties and catalysis of the USY zeolite were studied. The X-ray diffraction has been used to identify and quantify extra framework aluminum (EFAL) in USY zeolite by EFAL extraction using citric acid. The acid character changed depending on the EFAL concentration. The Lewis acid sites can be obtained from the Si/Al ratio. The removing of trace olefins was carried out over kinds USY zeolites with different amount of EFAL. The catalytic performance was correlated with the Lewis acid sites of USY.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Liquid adsorption of tobacco specific N-nitrosamines by zeolite and
           activated carbon
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Xiao Dan Sun , Wei Gang Lin , Lei-jun Wang , Bo Zhou , Xiao Lin Lv , Ying Wang , Sai-jing Zheng , Wei-miao Wang , Yi-Gang Tong , Jian Hua Zhu
      In order to control the tobacco specific nitrosamines (TSNA) pollution caused by smoking, liquid adsorption of TSNA in tobacco-extract solution by modified activated carbon, zeolites and other porous materials was systemically studied with the monitor of Liquid Chromatography–Tandem Mass Spectrometry (LC–MS/MS) technique. The effect of solid–liquid ratio, the porous structure and surface acidic-basicity of sorbent on the liquid adsorption was assessed. Among various activated carbon (AC) samples modified with acid soak, ion-exchange or impregnation, the impregnated sorbent ZnAC could remove 73% of the TSNA in the solution, offering a cost-effective candidate for potential industrial application. Zeolite CaA was also efficient to trap more than 40% of TSNA in tobacco solution, and the influence of cation on the adsorption of TSNA by zeolite and the possible selectivity for the components of TSNA such as NNN, NAT and NNK were carefully examined. Besides, the fabrication of optimal micro-environment for liquid adsorption of TSNA was explored.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Topology reconstruction from FAU to MWW structure
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Yanchun Shi , Enhui Xing , Xiuzhi Gao , Dongyun Liu , Wenhua Xie , Fengmei Zhang , Xuhong Mu , Xingtian Shu
      Topology reconstruction from FAU to MWW structure has been explored in the presence of hexamethyleneimine, NaOH and SiO2. The samples prepared at different crystallization stages were characterized by XRD, SEM, TEM, and 29Si/27Al/13C MAS NMR to investigate the intermediates in the topology reconstruction from FAU to MWW structure. It has been demonstrated for the first time that topology reconstruction from FAU to MWW structure was caused by the “synergism” of hexamethyleneimine, NaOH, and SiO2, which was supported by transformation from FAU to SOD structure without SiO2 and the preservation of FAU structure without NaOH. It is also clearly proved that FAU structure was directly reconstructed into MWW structure by the combination of all above mentioned characterizations, especially XRD and 29Si/27Al MAS NMR. MWW structure zeolite was generated at the consumption of FAU structure zeolite, which is worthy to be noticed that solid silica gel was completely consumed at the end of topology reconstruction. As shown in SEM and TEM images, MWW structure zeolite was reconstructed gradually from exterior to interior of FAU structure zeolite, which was clearly observed by the FAU–MWW co-existing zeolites as intermediate states. The reconstructed MWW structure zeolite has high relative crystallinity.
      Graphical abstract image

      PubDate: 2014-09-21T08:57:11Z
       
  • Adsorption of aniline on template-synthesized porous carbons
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Lina Zuo , Wenzhe Song , Taihong Shi , Can Lv , Juan Yao , JinFeng Liu , Yinghong Weng
      The aniline in aqueous solutions is harmful to both human health and the environment. A new synthetic, the templated porous carbon, was designed and studied in this study to adsorb the aniline from aqueous solutions. The templated porous carbon was synthesized by SBA-15 and natural zeolite and characterized by SEM/TEM /FTIR and N2 sorption/desorption isotherm analysis. The results indicated that the adsorption of aniline followed pseudo-second-order kinetic model and was well fit using the Freundlich isotherm model. The adsorption capacity was influenced by the pore structure and pH. The adsorption–desorption cycles were also investigated in this study, and the results suggested the template-synthesized porous carbon would be a promising adsorbent for the removal of aniline from aqueous solution.
      Graphical abstract image

      PubDate: 2014-09-16T08:46:02Z
       
  • Ionic liquid-assisted growth of Cu3(BTC)2 nanocrystals on graphene oxide
           sheets: Towards both high capacity and high rate for CO2 adsorption
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Zijun Bian , Xiang Zhu , Tian Jin , Jie Gao , Jun Hu , Honglai Liu
      Hierarchical porous metal organic framework (MOF) composites are highly demanded because they can keep the high activity and good transport property simultaneously. A novel method of ionic liquid-assisted growth of Cu3(BTC)2 on graphene oxide (GO) sheets was proposed and applied to improve both CO2 adsorption capacity and adsorption rate. Three ionic liquids (ILs) of triethylene tetramine acetate (TETA-Ac), triethylene tetramine tetrafluoroborate (TETA-BF4) and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) were used to investigate the effects of cations and anions of ILs on the structure of GO-IL/MOF composite. With amine or imidazole cations adsorbed at the surface of GO and the contrary anions closely attached, GO-ILs can provide a lot of active sites for the absorption of Cu2+ cations through the coordination. Just like a bridge, ILs assisted the initial growth of the first seed layer of Cu3(BTC)2 on the surface of GO. Among various GO-IL/MOF composites, GO-TAc/MOF-60 sample showed a superimposed structure, which lead to more accessible adsorption activity sites and shorten the transfer distance. Also, the GO sheets in GO-IL/MOF provide channels for faster transfer. It showed a high CO2 adsorption capability of 5.62mmol/g at 25°C and 100kPa, and a high CO2 kinetic separation performance as well. More importantly, the composite presented a quite good cyclic adsorption/desorption stability. The relations between the specific structures of the composites and the CO2 adsorption behaviors were tentatively demonstrated to reveal a convenient way for designing and fabricating hierarchical MOF composites.
      Graphical abstract image

      PubDate: 2014-09-16T08:46:02Z
       
  • Facile synthesis of novel flowerlike magnetic mesoporous carbon for
           efficient chlorophenols removal
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Shuangliu Liu , Sheng Li , Hongyun Niu , Tao Zeng , Yaqi Cai , Chunhong Shi , Beihai Zhou , Fengchang Wu , Xiaoli Zhao
      We present here a novel, low cost and environmental-friendly synthetic strategy for fabricating flowerlike magnetic mesoporous carbon (MMC) microspheres by using silica coated Fe3O4 as core, anisotropic layered double hydroxide (LDH) nanocrystals as hard template and dopamine as carbon source, respectively. The resulting MMC spheres has high surface areas (90.3m2 g− 1), excellent magnetic response (16.99emug− 1), and large mesopore volume (0.22cm3 g− 1), as well as good chemical inertness and mechanical stability. The MMC spheres were used to adsorb 2,4,6-trichlorophenol (TCP) from simulated water samples. Experiment results suggest that the adsorption was favorable at acidic pH and increased with the rise of initial TCP concentration and temperature. Kinetic parameters were proved to follow the pseudo-second-order kinetics model and the equilibrium data was more favorable for Freundlich isotherm. The equilibrium absorption capacity was 210mgg− 1 at initial TCP concentration of 20mgL− 1 and increased to 587mgg− 1 when the initial TCP concentration was up to 100mgL− 1, which was much higher than those of other carbon-based adsorbents reported in literature. To the best of our knowledge, this is the first report on the synthesis of flowerlike MMC material by using LDH as template and its application as adsorbent to remove TCP.
      Graphical abstract image

      PubDate: 2014-09-16T08:46:02Z
       
  • Nature of the active sites in Al-MCM-41 nano-structured catalysts for the
           selective rearrangement of cyclohexanone oxime toward ɛ-caprolactam
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Eliana G. Vaschetto , Gina A. Pecchi , Sandra G. Casuscelli , Griselda A. Eimer
      Al-MCM-41 type nano-structured catalysts with different Al contents were prepared by direct hydrothermal synthesis. All the materials were characterized by XRD, N2 adsorption, TEM, SEM, ICP-OES, FT-IR and adsorption of pyridine coupled to FT-IR spectroscopy. The relationship between the Al contents in the synthesis gel and final solid, the degree of Al introduction in tetrahedral coordination into the framework, the formation of nest silanols and the relative density of the acidic hydroxyl sites has been exhaustively analyzed. We could corroborate that hydroxyl groups present in silanol nests are the direct responsible of the weakly acid character of our materials. Moreover, a critical concentration of framework Al seems to be necessary to generate such nests, after which the acid sites density is strongly increased, according the framework Al amount increasing. The enhancement in the density of acidic nest silanols (active sites for the selective rearrangement of cyclohexanone oxime toward ɛ-caprolactam) reached by increasing the Al content, permitted to us achieve a cyclohexanone oxime conversion about 66%. The ɛ-caprolactam selectivity was 100% for all the evaluated catalysts, indicating that the acidic strength was kept sufficiently weak to not catalyze the formation of by-products.
      Graphical abstract image Highlights

      PubDate: 2014-09-16T08:46:02Z
       
  • Influence of porosity and methyl doping inside silica network: An electron
           diffraction and DFTB analysis
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Pradeep K. Singh , Jan M. Knaup , Sven Zimmermann , Steffen Schulze , Stefan E. Schulz , Thomas Frauenheim , Michael Hietschold
      The continuous scaling of transistor size towards deep submicron level demands an inevitable replacement of SiO2 with a low-k dielectric material. Doping of methyl groups in SiO2 network reduces the dielectric constant by replacing oxygen atoms bonded with silicon and creating a lower polarizable silicon methyl bond in the network. Further reduction in dielectric constant is possible by introducing porosity in the dense low-k network. The detailed knowledge about atomic structure of such low-k materials is a must for understanding their electronic and optical properties. In this study, electron diffraction and (density functional based tight binding) DFTB calculations are used to investigate the structure of dense and porous low-k dielectric materials. The radial distribution function (RDF) obtained from electron diffraction technique contains information about the short-range order present in the material. Bond lengths and bond angles determined from RDF indicate a significant modification occurring in the SiO2 network after doping with methyl groups. The local density of the materials is also derived from radial distribution function. It depends on the number and distances of nearest neighbors and was found to be decreased in these low-k materials compared with amorphous SiO2.
      Graphical abstract image

      PubDate: 2014-09-16T08:46:02Z
       
  • Synthesis of mesostructured indium oxide doped with rare earth metals for
           gas detection
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Haifeng Yang , Xuan Zhang , Junfang Li , Wentao Li , Guangcheng Xi , Yan Yan , Hua Bai
      Utilizing an improved one-step nanocasting method, ordered mesostructured In2O3 doped with different rare earth metals was synthesized. The obtained materials showed tunable doping ratios and ordered pore structure with high surface area, which led to remarkable sensitivity and selectivity for NH3 gas.
      Graphical abstract image

      PubDate: 2014-09-16T08:46:02Z
       
  • Periodic Mesoporous Organosilicas as adsorbents for the organic pollutants
           removal in aqueous phase
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Soliu O. Ganiyu , Cláudia Bispo , Nicolas Bion , Paula Ferreira , Isabelle Batonneau-Gener
      Heavy organic pollutants such as pesticides and pharmaceuticals are found in wastewater and are difficult to remove by microporous adsorbents because of their large size. Mesoporous organosilicas as potential adsorbents for removal of heavy organic pollutants from aqueous phase are investigated. Propylsulfonic acid-functionalized mesoporous silica (SBA-15-SO3H) and propylsulfonic acid-functionalized periodic mesoporous benzene-silica (Ph-PMO-SO3H) are prepared by co-condensation method. Textural and structural characterizations are conducted by X-ray diffraction, N2 physisorption, solid state NMR spectroscopy, elemental analysis and confirmed the structural integrity of the materials. Material adsorption behaviors are studied in pesticide, mesosulfuron methyl (MM), removal from aqueous phase. For all the materials, adsorption kinetics are well described by a pseudo-second order model indicating the chemisorption of the MM molecules via acid–basic interaction of the neutral form. Sorption isotherms are S-shape isotherms and can be well fitted by the Freundlich model. Ph-PMO-SO3H exhibits higher sorption rate (8.95mgg−1 h−1) and better sorption capacity (9.70mgg−1) than the mesoporous silica SBA-15-SO3H (4.16mgg−1 h−1, 9.4mgg−1). Furthermore, Ph-PMO-SO3H has also the best MM abatement rates in aqueous phase up to 95% for initial concentrations ranging from 4 to 10ppm than microporous acidic zeolite (HFAU) (∼70%) and mesoporous silica SBA-15-SO3H (∼70%). The phenyl groups in sulfonic PMO material seem to enhance organic pollutant adsorption capacity either by reducing wall hydrophilicity or by favoring the interaction with MM phenyl rings.
      Graphical abstract image Highlights

      PubDate: 2014-09-16T08:46:02Z
       
  • The synthesis of aluminophosphate and germanosilicate LTA using a
           triquaternary structure directing agent
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Joel E. Schmidt , Stacey I. Zones , Dan Xie , Mark E. Davis
      The use of triquaternary organic structure directing agents (OSDAs) for the synthesis of microporous materials is relatively unexplored. Here a triquaternary OSDA prepared by reacting 1,2-dimethylimidazole with 1,3,5-tris(bromomethyl)benzene promotes the formation of LTA in the aluminophosphate or germanosilicate reaction chemistries.
      Graphical abstract image Highlights

      PubDate: 2014-09-16T08:46:02Z
       
  • Hydrophobically modified spherical MCM-41 as nanovalve system for
           controlled drug delivery
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Aneesh Mathew , Surendran Parambadath , Sung Soo Park , Chang-Sik Ha
      Spherical MCM-41 nanovalve having hydrophobically modified pore channels was synthesized via surfactant assisted sol–gel methodology and post modification process. The spherical MCM-41 has been tailored as a smart pH responsive drug carrier system by the insertion of N-3-(trimethoxysilyl)propyl aniline (TMSPA) at the pore opening before extracting the surfactant and further with phenyltrimethoxysilane (PTMS) to impart hydrophobicity on the inner surfaces of the pore channels. The surfactant extracted MCM-41 exhibits excellent textural properties such as very high specific surface area (1307 m2 g−1), pore diameter (24 Å) and pore volume (0.65 cm3 g−1). The transmission electron microscope (TEM) and scanning electron microscope (SEM) images of mesosphere reflect the highly uniform and mono-dispersed spherical morphology having a particle size of 500nm. 5-Fluorouracil (5-Fu) and famotidine have been loaded into the hydrophobically modified channels followed with β-cyclodextrin (β-CD) as the gatekeeper to make the material as a pH responsive drug delivery system. The drug delivery has been carried out under in vitro condition at pH 4 and the amount of drug released from the nanovalve system was monitored by UV–Vis spectroscopy under regular intervals. The hydrophobically modified nanovalve was found to have delayed drug release of both 5-Fu and famotidine in comparison to the drug delivery from the nanovalve having unmodified pore channels synthesized from spherical MCM-41 under similar experimental conditions. The significance of functionalization as well as capping has been verified by the comparison of drug delivery behaviors among hydrophobically modified, unmodified, β-CD capped and uncapped nanocontainers.
      Graphical abstract image

      PubDate: 2014-09-16T08:46:02Z
       
  • Gas and liquid permeability in nano composites gels: Comparison of Knudsen
           and Klinkenberg correction factors
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Liz Anez , Sylvie Calas-Etienne , Juan Primera , Thierry Woignier
      We measured gas and water permeability in sets of nano-composite silica gels, (silica gel network with aerosil particles), which are highly porous but low permeability materials. Experimental results showed that gas and liquid permeability increased with aerosil content, allowing control of transport properties. Our results also showed that gas permeability was more than one order of magnitude higher than water permeability. This difference was analysed in view of the gas slippage effect. To this end, we tested and compared different correction factor models (Knudsen and Klinkenberg correction factors) proposed in the literature. We showed that the Klinkenberg factor increases with porosity, and discuss the effect of tortuosity. Models that account for porosity and tortuosity improve the accuracy of the prediction. The Knudsen correction increased the accuracy of the experimental data and made it possible to extrapolate the intrinsic permeability from the gas permeability with quite reasonable accuracy.
      Graphical abstract image

      PubDate: 2014-09-12T08:40:07Z
       
  • Synthesis of CuNi and CuNi/SBA-15 by aqueous method at room temperature
           and their catalytic activity
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): P. Hari Krishna Charan , G. Ranga Rao
      Here we report the room temperature synthesis of stable CuNi bimetallic alloy particles under aqueous conditions using cetyltrimethylammonium bromide surfactant and hydrazine hydrate as a reducing agent. The bimetallic particles are formed in situ by the reduction of Ni2+ ions to Ni0 by hydrazine. No additional base is added to maintain the pH of the aqueous solution during the synthesis. The reduction process is favoured by Cu nuclei which formed initially. Metallic Cu nuclei assist the growth of CuNi alloy particles of all compositions with nickel-rich kernel phases. The oxidation and hydrogen uptake behaviour of the CuNi particles are found to differ significantly due to the size and intrinsic variations in composition. CuNi particles are also embedded in SBA-15 matrix by similar co-reduction method. The catalytic properties of pristine and SBA-15 grafted CuNi bimetallic systems are studied by p-nitrophenol reduction.
      Graphical abstract image Highlights

      PubDate: 2014-09-12T08:40:07Z
       
  • Preparation, characterization and electrochemical properties of porous
           NiO/NPC composite nanosheets
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Yanli Tan , Qiuming Gao , Weiqian Tian , Yunlu Zhang , Jiandong Xu
      We present a facile combined hydrothermal and calcination method to prepare porous nickel oxide/nanoporous carbon (NiO/NPC) composite nanosheets. The material is characterized by powder X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM), X-ray photoelectron spectrometer (XPS), as well as N2 sorption analyses. Cyclic voltammetry (CV) and galvanostatic charge–discharge tests are performed and indicate that the NiO/NPC possesses superior pseudocapacitive performance with the specific capacitance value of 1337Fg−1 at the current density of 2Ag−1 using as the electrode material. The specific capacitance value of 457Ag−1 can be obtained at the high current density of 10Ag−1 showing its high rate performance. The material exhibits good cycling stability by retaining 95% of the max capacitance after 500 cycles of continuous charge–discharge processes. Adding NPC in the synthetic process not only changes the elemental composition, but also leads to more Ni3+ ions and abundant pores in the texture of the NiO/NPC material, which provides high electron conductivity and fast ion transport, enhances the rate performance of the NiO/NPC electrode, and stabilizes the active material.
      Graphical abstract image

      PubDate: 2014-09-12T08:40:07Z
       
  • Changes of medium-range structure in the course of crystallization of
           zeolite omega from magadiite
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Miao Cui , Yifu Zhang , Xiaoyu Liu , Lin Wang , Changgong Meng
      Changes of medium-range structure during the crystallization of zeolite omega from magadiite were characterized. It is found that although the long-range order of magadiite is collapsed in the initial stage, parts of 5-member rings and 6-member rings are still preserved as secondary building units. The fraction of 5-member rings and 6-member rings increases as the crystallization progresses. The 4-member ring chains are formed at a stage later than that of 5-member rings and 6-member rings.
      Graphical abstract image

      PubDate: 2014-09-12T08:40:07Z
       
  • Editorial Board
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199




      PubDate: 2014-09-06T08:19:33Z
       
  • Introducing a self-consistent test and the corresponding modification in
           the Barrett, Joyner and Halenda method for pore-size determination
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Jhonny Villarroel-Rocha , Deicy Barrera , Karim Sapag
      A standard method to obtain the mesopore size distribution of adsorbents is the Barrett, Joyner and Halenda (BJH) analysis of the N2 adsorption–desorption isotherm at 77K. The availability, over the last two decades, of well-defined model adsorbents in the mesopore range, together with other forms of isotherm analysis with the help of the Density Functional Theory (DFT) has shown that the BJH method tended to underestimate the pore-width when they are smaller than 10nm. Regarding this fact, we have reported an improved BJH method, where we have remarked that the reconstruction of the adsorption–desorption isotherm from the BJH results leads to some inconsistency. We therefore proposed a simple means to cancel the mentioned discrepancy and inconsistency. This correction can be made by simply adding a corrective term to the standard BJH equation, which value is selected to meet a self-consistent criterion, i.e. the reconstructed isotherm should fit the original one. In the first article, the method was applied for some ordered mesoporous materials (OMM) synthesized in our laboratory, showing only the results without major details. In this work, we validate the test for other samples, in other pore size ranges, introducing some remarks in theoretical aspects and in the importance of obtaining and taking into account the micropore volume. Finally, a detailed procedure to apply the proposal method using only the experimental data of the analysis is presented.
      Graphical abstract image

      PubDate: 2014-09-06T08:19:33Z
       
  • Hydrothermal conversion of Fe2O3/SiO2 spheres into Fe2O3/Silicalite-1
           nanowires: Synthesis, characterization, and catalytic properties
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Pengfei Xie , Lifeng Chen , Zhen Ma , Chengyun Huang , Zhiwei Huang , Yinghong Yue , Weiming Hua , Yi Tang , Zi Gao
      Fe2O3 nanoparticles were dispersed onto SiO2 by impregnating amorphous SiO2 spheres with Fe(NO3)3 followed by spray drying and calcination. Interestingly, the amorphous SiO2 spheres in the sample could be converted into Silicalite-1 nanowires after being hydrothermally treated in the presence of a mixture of ethylenediamine and triethylamine (dual templates) for over 4days, whereas the Fe2O3 nanoparticles were still highly dispersed on the formed Silicalite-1 nanowires. Meanwhile, a fraction of Fe(III) species entered the zeolitic framework. Relevant characterization was conducted using X-ray fluorescence (XRF), N2 adsorption–desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, electron paramagnetic resonance (ESR), X-ray photoelectron spectroscopy (XPS), and H2-temperature-programmed reduction (H2-TPR). The catalytic properties of the samples were studied using CO oxidation, N2O decomposition, and selective reduction of NO as probe reactions.
      Graphical abstract image

      PubDate: 2014-09-06T08:19:33Z
       
  • A nickel foam supported copper core/nickel oxide shell composite for
           supercapacitor applications
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): J.L. Yin , J.Y. Park
      Micro porous and branched copper/nickel oxide composite with novel core–shell structure was fabricated on the nickel foam by using two consecutive electroplating processes and normally used electrochemical oxidation process. Nickel foam was used as the current collector to deposit more electroactive material, and it also helped to rapidly disperse hydrogen bubbles generated during the copper electroplating process. Field emission-scanning electronic microscopy (FE-SEM) images showed that mesoporous NiO wrinkles with lateral sizes of tens of nm were well grown and dispersed on the surface of 3-dimensional copper core. The electrochemical measurements of the as prepared Ni foam/Cu/NiO composite were performed to determine its performances. A maximum specific capacitance of 416F/g and energy density of 11.2Wh/kg at the 3.6kW/kg were obtained, indicating its excellent ions accessibility and charge storage ability. Moreover, the developed composite material exhibited low inner resistance (0.6Ω) and good cycling performance along with 71.1% specific capacitance retained after 5000 cycles. These results reveal that the developed composite electrode could be a promising positive electrode candidate material for supercapacitor applications.
      Graphical abstract image Highlights

      PubDate: 2014-09-06T08:19:33Z
       
  • Dual-responsive drug delivery system with real time tunable release
           behavior
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Fang Li , Yingchun Zhu , Yunli Wang
      A dual-responsive drug delivery system (DDS) was successfully established by coating functional macromolecules onto the outlets of mesoporous silica nanospheres. Electro-sensitive and thermally responsive units were copolymerized into the macromolecular networks to control the drug release under different circumstances. The simulated drug delivery experiments conducted in vitro revealed that the drug release rate could be regulated continuously and remotely by one or both stimuli sources. The drug release rate under 0.5Hz alternating electric field was almost twice as much as that without an alternating electric field. This combination of electro-responsive function and temperature sensitive characteristics could lead to a real time tunable drug delivery system with wide application area.
      Graphical abstract image Highlights Electro- and thermo-responsive drug release (DFMS) system for real time tunable drug delivery application.

      PubDate: 2014-09-06T08:19:33Z
       
  • Deblocking effect of carbonates and hydrogen carbonates in the alkali form
           zeolites with narrow pores
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): A.V. Larin
      The alkali forms of MeRHO zeolite (Me=Li, Na, K, Cs) are studied theoretically at the DFT/PBE level using projector augmented wave method (PAW) and periodic boundary conditions (PBC). The equilibrium positions of the Me cations have been optimized at the D8R prisms where they control molecular transport in the pores of MeRHO. The effect of the displacement of alkali cations has been estimated due to coordination of both carbonate or hydrogen carbonate anions that can also induce RHO framework transformations. Admitting the CO3 −2 and HCO3 − formations via the reactions between H2O and CO2, the energy of respective reactions was evaluated at various Si/Al moduli and analyzed regarding possible influence on the gas adsorption.
      Graphical abstract image Highlights

      PubDate: 2014-09-06T08:19:33Z
       
  • MnO2 nanowires in situ grown on diatomite: Highly efficient absorbents for
           the removal of Cr(VI) and As(V)
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Yucheng Du , Guangwei Zheng , Jinshu Wang , Liping Wang , Junshu Wu , Hongxing Dai
      The MnO2 nanowires-deposited diatomite samples were prepared using the hydrothermal method with KMnO4 and (NH4)2S2O8. Physicochemical properties of the samples were characterized by means of numerous techniques, and their efficiency for the removal of Cr(VI) and As(V) was determined. The parameters, such as pH value, adsorption time, adsorbent mass, and initial Cr(VI) or As(V) concentration, could influence the Cr(VI) and As(V) removal efficiency or adsorption capacity of the MnO2 nanowires/diatomite sample obtained after hydrothermal treatment at 90°C for 12h. These MnO2 nanowires/diatomite samples showed high surface areas and superb Cr(VI) and As(V) adsorption behaviors, with the maximum Cr(VI) and As(V) adsorption capacities being 197.6 and 108.2mg/g, respectively. The Cr(VI) and As(V) adsorption mechanisms of the samples were also discussed.
      Graphical abstract image

      PubDate: 2014-09-06T08:19:33Z
       
  • Adsorption of volatile hydrocarbons in iron polysulfide chalcogels
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Ejaz Ahmed , Alexander Rothenberger
      We report the synthesis, characterization and possible applications of three new metal-chalcogenide aerogels KFe3Co3S21, KFe3Y3S22 and KFe3Eu3S22. Metal acetates react with the alkali metal polychalcogenides in formamide/water mixture to form extended polymeric frameworks that exhibit gelation phenomena. Amorphous aerogels obtained after supercritical CO2 drying have BET surface area from 461 to 573m2/g. Electron microscopy images and nitrogen adsorption measurements showed that pore sizes are found in micro (below 2nm), meso (2–50nm), and macro (above 50nm) porous regions. These chalcogels possess optical bandgaps in the range of 1.55–2.70eV. These aerogels have been studied for the adsorption of volatile hydrocarbons and gases. A much higher adsorption of toluene in comparison with cyclohexane and cyclopentane vapors have been observed. The adsorption capacities of the three volatile hydrocarbons are found in the following order: toluene>cyclohexane>cyclopentane. It has been observed that high selectivity in adsorption is feasible with high-surface-area metal chalcogenides. Similarly, almost an eight to ten times increase in adsorption selectivity towards CO2 over H2/CH4 was observed in the aerogels. Moreover, reversible ion-exchange properties for K+/Cs+ ions have also been demonstrated.
      Graphical abstract image Highlights

      PubDate: 2014-09-01T08:05:22Z
       
  • Methoxylation of α-pinene over mesoporous carbons and microporous
           carbons: A comparative study
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Inês Matos , Marta F. Silva , Ramiro Ruiz-Rosas , Joaquim Vital , José Rodríguez-Mirasol , T. Cordero , José E. Castanheiro , Isabel M. Fonseca
      A biomass derived carbon, a commercial microporous carbon and a xerogel mesoporous carbon catalysts were used in the study of α-pinene methoxilation reaction and the influence of textural and physical–chemical properties of the carbons was evaluated. Biomass carbon presented the higher activity, whereas the commercial one is the less active in the conditions studied. The main product of the reaction was α-terpinyl methyl ether and good values of selectivity were obtained over all the catalysts. A kinetic model was developed assuming that the α-pinene is consumed according to the parallel reaction network. The kinetic model presents high quality fittings to the experimental concentration profiles. These results show that it is possible to activate a waste residue using H3PO4 and convert it to high added value product such as acid catalyst.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • Immobilization of laccase on hairy polymer grafted zeolite particles:
           Degradation of a model dye and product analysis with MALDI–ToF-MS
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Omur Celikbicak , Gulay Bayramoglu , Meltem Yılmaz , Gozde Ersoy , Niyazi Bicak , Bekir Salih , M. Yakup Arica
      Poly(2-chloroethyl acrylate), p(CEA), as a functional polymer was grafted via surface initiated atom transfer radical polymerization (SI-ATRP) on zeolite particles. The p(CEA) grafted zeolite particles were aminated, and a ligninolytic enzyme “laccase” from Trametes versicolor was covalently immobilized on the composite particles via glutaraldehyde coupling. The amount of immobilized laccase on the zeolite-g-p(CEA) particles was determined as 17.7mgg−1 particles. The degradation of a model dye (i.e., Reactive Red 120; RR-120) with the free and immobilized laccases was evaluated in batch and continuous systems. The covalently immobilized laccase showed a high decolorization efficiency toward RR-120 in aqueous solution compared to the free counterpart. The resulting dye degradation products were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI–ToF-MS).
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • Hydrothermal synthesis of high purity zeolite A from natural kaolin
           without calcination
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Jing-Quan Wang , Ya-Xi Huang , Yuanming Pan , Jin-Xiao Mi
      Zeolite A is a commercially and environmentally important microporous material, which is commonly synthesized from calcined kaolin. One major drawback inherent to this approach is that the properties (i.e., purity, particle size, morphology, and cation-exchange capacity) of the final product depend largely on the quality of the raw kaolin ores. Herein we report on a new hydrothermal route for the synthesis of high purity zeolite A with controllable particle size and morphology, from natural kaolin without conventional high temperature calcination. This route starts with hydrothermal reaction of natural kaolin with NaOH to form hydrous sodium aluminosilicates (i.e. hydroxycancrinite and nepheline hydrate), which are then dissolved in dilute HCl. The resulting acid solution, after filtration to remove unreacted impurity minerals such as quartz and muscovite, is then adjusted to pH=7 to form an amorphous Si and Al gel, which is used for the hydrothermal synthesis of zeolite A. A comparative study of zeolite A samples synthesized from this new route and those from the conventional calcination method reveals that the former have more controllable size and morphology than the latter, giving rise to higher brightness and enhanced cation-exchange capacity. Another major advantage of this new method is that the common impurity minerals such as quartz, muscovite and feldspars in natural kaolin can be removed, giving rise to high purity zeolite A and possibly expanding this technique to the use of low-grade kaolin.
      Graphical abstract image Highlights A new hydrothermal route has been developed for the synthesis of high purity zeolite A with controllable particle size and morphology, from natural kaolin without high temperature calcination.

      PubDate: 2014-09-01T08:05:22Z
       
  • Versatile drug releaser derived from the Ti-substituted mesoporous silica
           SBA-15
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Mi Mi Wan , Xiao Dan Sun , Shuai Liu , Jing Ma , Jian Hua Zhu
      Multiple modification of SBA-15 in its electrostatic and geometric properties was simultaneously performed by titanium substitution in the framework of mesoporous silica, in order to fabricate versatile drug releaser based on the Ti-SBA-15 with subtle “critical state”. The SBA-15 with proper Ti-content, no more than 4.2μmolg−1 without formation of TiO2, was synthesized via special hydrothermal conditions with assistance of fluorine ion, and the resulting composite had the appropriately distorted mesoporous structure provided the Si/Ti of initial gel no less than 50, plus the lowered surface negative charge (Zeta-potential). The controlled Ti-substitution enabled SBA-15 to be more active in adsorbing negative charged drug like heparin, especially in dilute solution. Also, sustained heparin release was achieved on the Ti-SBA-15 with a little initial burst. Ti-substitution also improved the loading and release of small drug such as ibuprofen on SBA-15, compensating the lack of fine geometric confinement in mesoporous silica. Moreover, liquid adsorption of probes with different negative charge and molecular size, including heparin, ibuprofen and volatile nitrosamines N-nitrosopyrrolidine was investigated to explore the influence of Ti-substitution on the electrostatic attraction and structural distortion of SBA-15, offering a tool to characterize the mesoporous materials and providing a valuable clue for design of new drug releaser.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • Superhydrophobic hybrid aerogel powders from waterglass with distinctive
           applications
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Maria de Fátima Júlio , Laura M. Ilharco
      Hybrid silica aerogel powders with enhanced superhydrophobicity and very high reaction yield were prepared by a fast co-precursor method at ambient pressure. An inexpensive aqueous sodium silicate solution was used as starting material (waterglass or WG), with hexamethyldisilazane (HMDZ) as organic co-precursor. The key for successfully achieving such high yields and superhydrophobicity was a systematic tuning of the synthesis parameters (co-precursors and acid catalyst molar ratios) and process conditions (stirring speed, stirring period, aging, washing and drying steps), in close correlation with the reaction mechanism. Using a minimum amount of organic co-precursor, a total yield of ∼80% in hybrid aerogels with high lipophilic/hydrophilic ratio, very high water contact angles (∼152±2°) and very low densities (∼0.120gcm−3) were obtained. The optimized synthesis conditions consist in HNO3:WG:HMDZ molar ratios of 1.5:1.0:1.5, stirring speed of 120rpm, only during addition of the catalyst and co-precursor, aging for 5min and washing with water before drying at atmospheric pressure. The minimization of the only costly precursor allows envisaging a low-cost large scale production and, moreover, the encapsulation of water droplets within aerogel powder allows proposing distinctive applications, such as water transport at a microscale level.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • One-step approach for synthesis of nanosized Cu-doped zeolite A crystals
           using the Cu–EDTA-complex
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Ivan Yordanov , Inna Karatchevtseva , Hubert Chevreau , Maxim Avdeev , Rohan Holmes , Gordon Thorogood , Tracey Hanley
      Copper-doped nanosized zeolite A crystals were synthesized by an in situ templating approach using [Cu(EDTA)]2−-complex. The structural properties of the copper containing zeolite crystals were characterized by a suite of different techniques including SEM–EDX, ESR, mid-IR and Far-IR, Raman, in situ XRD and non-ambient neutron powder diffraction. The SEM investigations on the morphology show spheroidal zeolite A crystals with average size ∼200nm. The asymmetric ESR spectrum shows that the Cu2+ ion is in a tetragonal-distorted octahedral crystal field. FT-IR and Raman spectroscopies provide information on coordination environment of the copper ion. The band due to stretching vibration of C–N bond, where N is coordinated to the copper ion (C–N–Cu), was observed at 1109cm−1 in the mid-infrared region. The Raman band due to the Cu–O bond is present at 630cm−1 indicating the coordination of the Cu2+-cation to COO−-group of the EDTA-ion. The XRD data shows an enlarged d-spacing between the adjacent zeolite lattice planes due to the presence of the [Cu(EDTA)]2−-complex in comparison to template-free LTA zeolite structure. LeBail fitting approach on temperature-dependent in situ X-ray and neutron diffraction profiles have demonstrated the expansion of the zeolite cell during the thermal treatment followed by subsequent contraction with the decomposition of the organic template.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • Synthesis of thermally stable porous SiC hollow spheres and control of the
           shell thickness
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Seong-Cheol Noh , Seung-Young Lee , Sungrye Kim , Sungho Yoon , Yong Gon Shul , Kwang-Deog Jung
      Thermally stable SiC hollow spheres were prepared using SiO2 templates with two layers. At the calcination at higher than 1300°C, the SiC hollow sphere could be obtained. The shell thickness of the porous SiC hollow spheres can be controlled by the molar ratio of TMS/TEOS. The pore volumes and BET surface areas of the template SiO2 increased with the molar ratio of TMS/TEOS, while those of the SiC/SiO2 and SiC spheres decreased. It is evident that the pore sizes of the SiC hollow spheres were not influenced by the TMS/TEOS ratio. The wall thickness of the SiC sample increased with an increase in the TMS/TEOS mole ratio. The prepared SiC hollow spheres with the surface area higher than 770m2/g were thermally stable up to temperatures higher than 700°C.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • An novel approach to synthesize layered material PLS-4
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Zhengjia Li , Kun Jiao , Xiangyu Xu , Jiaqing Song
      A novel synthetic route to the layered material PLS-4 has been developed using amorphous silica as the silica source and ethyldimethylethanolammonium fluoride as the organic structure-directing agent. This reaction can proceed under high concentration conditions utilizing quaternary ammonium fluoride salt rather than ammonium fluoride or hydrofluoric acid. By introducing aluminum, alkali metal and alkaline earth metal into the aforementioned system, three new morphologies have been obtained. Products were fully characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption analyses.
      Graphical abstract image Highlights

      PubDate: 2014-09-01T08:05:22Z
       
  • Synthesis of 1,10-phenanthroline functionalized periodic mesoporous
           organosilicas as metal ion-responsive sensors
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Bing Xiao , Jiao Zhao , Xiao Liu , Peiyuan Wang , Qihua Yang
      The periodic mesoporous organosilicas with 1,10-phenanthroline (Phen) integrated in the framework (Phen-PMOs) were synthesized by co-condensation of tetramethoxysilane (TMOS) and the phenanthroline bridged organosilicas (Phen-Si) using triblock copolymer P123 as a template in weak acidic medium. The FT-IR, 13C CP-MAS and 29Si MAS NMR characterizations confirmed the integration of phenanthroline ligand in material. The Phen-PMOs have ordered 2-D hexagonal mesostructure though the structural order decreases with the increment in Phen content based on XRD and TEM characterizations. The hybrid materials exhibited specific surface area of 328–106m2/g and total pore volume of 0.43–0.17cm3/g. These Phen-functionalized PMOs, with strong blue fluorescent emission originated from phenanthroline group in the framework, have potential application in recognition of different metal ions, with luminescence intensity sensed to the type and concentration of the metal ions.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • Study of the influence of physical–chemical properties of steamed
           H-MOR zeolites in the mechanism of adsorption of fatty acids and their
           esterification
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Luis F. Isernia
      The increasing use of fatty acid esters, on the industry and the substitution of traditional petroleum fuels, promotes the study of heterogeneous catalysts with a better environmental performance than their homogeneous counterparts. The mordenite, has attracted special attention, for its environmental friendliness, exceptional physical chemical properties and the availability of large natural deposits. In order to study the influence of its physical chemical properties over the mechanism of adsorption of fatty acids (FA) and their esterification, three new solids were obtained through hydrothermal treatment at 800–1000K of a mordenite with a Si/Al ratio of about six. The characterization by FTIR and XRD confirms the collapse of crystallinity with the increase of the treatment temperature. The partial exiting of tetrahedral aluminum out of the crystalline network, revealed by 29Si and 27Al MAS NMR leads to the diminution of the acidity and the increasing hydrophobicity, evidenced by FTIR spectroscopy and adsorption isotherms of stearic acid. The kinetic evaluation of FA esterification reveals a pseudo-second order model. These results suggest a change in the adsorption mechanism: In the original mordenite and treated at low temperatures, a higher density of acid sites favors the adsorption of the carboxyl group of FA molecules by hydrogen-bonding to the zeolite Al–OH–Si groups, while the tails adsorb on the less polar surroundings. At greater treatment temperatures, the taller hydrophobicity induces the adsorption of the FA molecules onto the lesser polar (and lesser active) sites of the zeolite with its carboxyl groups oriented away from the zeolitic surface.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • A first principle study on Fe incorporated MTW-type zeolite
    • Abstract: Publication date: 15 November 2014
      Source:Microporous and Mesoporous Materials, Volume 199
      Author(s): Gang Feng , Zhang-Hui Lu , Deqin Yang , Dejin Kong , Jianwen Liu
      The distribution scheme of Fe3+ cation in MTW-type zeolite and its influence on the acid property were systematically studied using dispersion-corrected density functional theory. The calculated energy differences are small for different incorporated T sites, indicating that Fe atoms might distribute in all kinds of T sites. Substitution energy is firstly introduced to evaluate relative synthesis difficulty for metal incorporated zeolite. For MTW-type zeolites, the calculated substitution energies give the order of NaAl-MTW>NaFe-MTW>NH4Al-MTW>NH4Fe-MTW>HAl-MTW>HFe-MTW, which are in line with experimental observations, illustrating a real case that substitution energies can be used to pre-select the prescriptions for zeolite synthesis. Acidity studies show that the Lewis acidities of HFe-MTW zeolite are stronger than those of HAl-MTW zeolite, while the Brønsted acidities of HFe-MTW zeolite are weaker than those of HAl-MTW zeolite. Adsorption studies of NH3 and pyridine show that adsorption on the Lewis acid sites are less stable than on the Brønsted acid sites. These results are also in well agreement with the previous experimental observations and provide new insights for MTW-type zeolites.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
  • Effectiveness of the reversible structural conversion of MWW zeolite for
           preparation of interlayer-expanded Ti-MWW with high catalytic performance
           in olefin epoxidation
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Masato Yoshioka , Toshiyuki Yokoi , Takashi Tatsumi
      Interlayer-expanded MWW-type titanosilicate, Ti-IEZ-MWW, has been successfully prepared through the reversible structural conversion (RSC) of the MWW zeolite. First, the layered precursor of the MWW titanosilicates, Ti-MWW(P), was treated in an aqueous solution of HNO3 to remove octahedrally-coordinated Ti species in Ti-MWW(P) (Ti-MWW(P)-AT). This acid-treatment led to the partial removal of piperidine molecules, which served as pillaring species between the MWW layers as well as the structure-directing agent for the MWW-type zeolite, resulting in the condensation of silanol on the layer surface and formation of the three-dimensional (3D) MWW structure. Next, to promote the structural rearrangement from the 3D MWW structure to the original layered precursor, Ti-MWW(P)-AT was hydrothermally treated in the aqueous solution containing piperidine, forming a layered material (Ti-MWW(P)-RSC), which has almost the same structure as Ti-MWW(P). Finally, the interlayer silylation of Ti-MWW(P)-RSC was performed using diethoxydimethylsilane under acidic conditions. Thus prepared material, Ti-IEZ-MWW-RSC, contained unique framework Ti species and showed a higher catalytic activity in the epoxidation of cyclohexene with H2O2 compared to Ti-IEZ-MWW directly prepared from Ti-MWW(P) as well as the conventional 3D Ti-MWW.
      Graphical abstract image Highlights Interlayer-expanded MWW-type titanosilicate has been successfully prepared by utilizing the structural reversibility between the 3D crystalline and the layered structures.

      PubDate: 2014-09-01T08:05:22Z
       
  • Gas adsorption separation of CO2/CH4 system using zeolite 5A
    • Abstract: Publication date: December 2014
      Source:Microporous and Mesoporous Materials, Volume 200
      Author(s): Masoud Mofarahi , Fatemeh Gholipour
      Pure gas adsorption isotherms of carbon dioxide at (273, 283, 303, 323, 343)K and binary adsorption isotherms of carbon dioxide and methane at (303, 323)K and pressures up to 10bar on Zeochem Co. Zeolite 5A were measured using a volumetric method. Equilibrium gas phase compositions have been determined using a gas chromatograph (GC). The experimental binary equilibrium data were compared with equilibrium data calculated by ideal adsorbed solution theory (IAST), and vacancy solution model (VSM). A model analysis of the experimental data has been performed with real adsorbed solution theory (RAST) owing to not satisfactory prediction of multi-component behavior with IAST and VSM. For this purpose, activity coefficients, accounting for the non-ideality of the adsorbed mixture, were calculated from the experimental data. The results of the pure experimental data showed that, the heat of adsorption for methane is approximately independent of loading (about 20kJ/mol), and for carbon dioxide decreases by increasing loading when q <0.5mol/kg. Subsequently, by increasing loading, the heat of adsorption increases up to q =2mol/kg. The selectivity of both simulated landfill and biogas mixtures have been also measured experimentally. These data indicated that zeolite 5A can be successfully applied in CO2/CH4 separation for landfill gas and biogas upgrading.
      Graphical abstract image

      PubDate: 2014-09-01T08:05:22Z
       
 
 
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