for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> PHYSICS (Total: 801 journals)
    - ELECTRICITY AND MAGNETISM (9 journals)
    - MECHANICS (21 journals)
    - NUCLEAR PHYSICS (49 journals)
    - OPTICS (86 journals)
    - PHYSICS (578 journals)
    - SOUND (25 journals)
    - THERMODYNAMICS (33 journals)

PHYSICS (578 journals)

The end of the list has been reached or no journals were found for your choice.
Journal Cover Microporous and Mesoporous Materials
  [SJR: 1.243]   [H-I: 116]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1387-1811
   Published by Elsevier Homepage  [3034 journals]
  • Selective cyclohexane oxidation over vanadium incorporated silica pillared
           clay catalysts: The effect of VOx content and dispersion
    • Authors: Xinyu Lyu; Huihui Mao; Kongnan Zhu; Yong Kong; Motoyoshi Kobayashi
      Pages: 1 - 9
      Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Xinyu Lyu, Huihui Mao, Kongnan Zhu, Yong Kong, Motoyoshi Kobayashi
      The design of efficient and stable clay based materials for catalytic technologies is a great challenge. We demonstrated a new approach of fabricating vanadium incorporated silica-pillared clay by interlayered self-assembly synthetic route. And such synthetic route utilized tartaric acid as the complexing reagent, both dodecyl dimethyl benzyl ammonium bromide and octadecylamine as the mixed structure-directing agent. The obtained vanadium-containned silica-pillared clay samples were characterized by X-ray fluorescence, X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier-transform infrared spectroscopy, diffuse reflectance ultraviolet–visible spectroscopy and X-ray photoelectron spectroscopy techniques. Characterization results indicate that there is an important correlation between the concentration of octadecylamine and uniform structure of the obtained vanadium-containned sample. The octadecylamine is not only used as swelling agency but also decreases the polarity to confirm the uniform mesoporous structure form in the interlayered regions. It was generally considered that hydrothermal synthesis bears the advantage of incorporating active metal ions into the framework in the tetrahedral coordination with V4+ state under the combined action of complexing reagent and mixed structure-directing agent. And the V2O5 phase was gradually formed via aggregation and agglomeration of increasing highly dispersed vanadium species. The catalytic behaviour and performance was examined using the selective oxidation of cyclohexane. The obtained catalyst possesses larger surface area and mesoporous volume and uniform slit-shaped mesopores, which are beneficial to the diffusion of the vanadium atom and responsible for higher yield of the KA oil. And the mechanism associated with the porous structure change has also been discussed.
      Graphical abstract image

      PubDate: 2017-06-17T04:17:03Z
      DOI: 10.1016/j.micromeso.2017.06.014
      Issue No: Vol. 252 (2017)
       
  • Synthesis, characterization, and catalytic application of hierarchical
           SAPO-34 zeolite with three-dimensionally ordered mesoporous-imprinted
           structure
    • Authors: Jing Wang; Mengfei Yang; Wenjin Shang; Xiaoping Su; Qingqing Hao; Huiyong Chen; Xiaoxun Ma
      Pages: 10 - 16
      Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Jing Wang, Mengfei Yang, Wenjin Shang, Xiaoping Su, Qingqing Hao, Huiyong Chen, Xiaoxun Ma
      Hierarchical SAPO-34 zeolites with three-dimensionally ordered mesoporous-imprinted structure (3DOm-i SAPO-34) were first confined synthesized within three-dimensionally ordered mesoporous carbons by multiple hydrothermal (MHT) treatments. With perfect structure replication, the obtained 3DOm-i SAPO-34 zeolite particles exhibited unique ordered structures consisting of primary spherical elements of sizes determined by mesopore cages of the corresponding carbon templates, and the sizes of mesopores constituted by the adjacent spherical elements can be precisely tuned from 5.5 to 13.0 nm by varying the 3DOm carbon. The as-synthesized hierarchical 3DOm-i SAPO-34 catalysts showed superior catalytic performance in the MTO reaction with prolonged catalytic lifetime and significant improvement of selectivity for light olefins (ethylene and propylene) compared to the conventional microporous SAPO-34.
      Graphical abstract image

      PubDate: 2017-06-17T04:17:03Z
      DOI: 10.1016/j.micromeso.2017.06.012
      Issue No: Vol. 252 (2017)
       
  • Adsorption of acetic acid and methanol on H-Beta zeolite: An experimental
           and theoretical study
    • Authors: Glaucio J. Gomes; M. Fernanda Zalazar; Cleber A. Lindino; Fernando R. Scremin; Paulo R.S. Bittencourt; Michelle Budke Costa; Nélida M. Peruchena
      Pages: 17 - 28
      Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Glaucio J. Gomes, M. Fernanda Zalazar, Cleber A. Lindino, Fernando R. Scremin, Paulo R.S. Bittencourt, Michelle Budke Costa, Nélida M. Peruchena
      The adsorption of acetic acid and methanol on H-Beta zeolite as a model of reaction of first step of the esterification reaction has been investigated with TGA-IR coupled, ATR-FTIR spectroscopy together with Density Functional Theory (DFT) calculations at M06–2X/6-31G(D) level. From the theoretical viewpoint, different models of adsorption of acetic acid and methanol on the surface of H-Beta zeolite are studied. TGA-IR experiments show that both reactants are molecularly adsorbed on H-Beta, beyond 200 °C for methanol and 250 °C for acetic acid other species are also formed due to the surface reactivity being strongly adsorbed on the catalyst. Results from ATR-FTIR spectroscopy and theoretical calculations reveal that the predominant adsorption mode of acetic acid involves the ads_AA(CO) complex where the acetic acid is molecularly adsorbed by the carbonyl group on the Brønsted acid site of catalyst, and the OH group is oriented to the Al-O-Si bridge. The mechanism of adsorption of both acetic acid and methanol is also discussed at molecular level. The complexes where the acetic acid is adsorbed by the carbonyl group are clearly the most stable one.
      Graphical abstract image

      PubDate: 2017-06-17T04:17:03Z
      DOI: 10.1016/j.micromeso.2017.06.008
      Issue No: Vol. 252 (2017)
       
  • Fluoride-mediated synthesis of TON and MFI zeolites using
           1-butyl-3-methylimidazolium as structure-directing agent
    • Authors: Christian W. Lopes; Luis Gómez-Hortigüela; Alex Rojas; Sibele B.C. Pergher
      Pages: 29 - 36
      Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Christian W. Lopes, Luis Gómez-Hortigüela, Alex Rojas, Sibele B.C. Pergher
      In this work, 1-butyl-3-methylimidazolium (1B3MI) cation has been employed as a structure-directing agent for the synthesis of pure silica and Ti-containing zeolites in fluoride media. The 1B3MI OSDA exhibited distinct phase selectivity depending on the synthesis conditions, and particularly the concentration of the synthesis gel. Thus, under more diluted conditions (H2O/SiO2 = 14), the 1B3MI cation yielded pure silica TON zeolite with high crystallinity. Attempts to obtain Ti-containing zeolites, however, failed at this diluted condition even after 15 days of synthesis. In contrast, highly crystalline Ti-MFI was the only phase obtained upon reducing the H2O/SiO2 molar ratio from 14 to 7. The presence of Ti in the MFI zeolite framework was confirmed by both infrared and DRS UV-vis spectroscopies. The presence of intact OSDA molecules within the micropores was inferred from elemental analysis and 13C CP-MAS NMR spectroscopy. On the other hand, thermogravimetric analyses showed a different packing of the 1B3MI cation in the pure silica TON and Ti-MFI samples. Moreover, the environments for Si and F species in the as-made materials were investigated by means of 29Si and 19F MAS NMR, respectively. Finally, molecular simulations showed that the most stable arrangement of the 1B3MI cations involves the location of the imidazolium rings on the channel intersections and of the butyl chains on the sinusoidal channels.
      Graphical abstract image

      PubDate: 2017-06-17T04:17:03Z
      DOI: 10.1016/j.micromeso.2017.06.017
      Issue No: Vol. 252 (2017)
       
  • Insight into oil and gas-shales compounds signatures in low field 1H NMR
           and its application in porosity evaluation
    • Authors: I. Habina; N. Radzik; T. Topór; A.T. Krzyżak
      Pages: 37 - 49
      Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): I. Habina, N. Radzik, T. Topór, A.T. Krzyżak
      The low field 1H NMR characterization of rock components that are specific for oil- and gas- shales is presented. 1D T2 distributions together with T1-T2 maps and T1/T2 ratios for the samples of smectite, illite, illite-smectite, kaolinite, chlorite and kerogen served to obtain characteristic features. T1-T2 maps measured in three saturation states (native, saturated and dried) allowed the observation of different fractions of water such as water confined in interlayer spaces, filling pore spaces and hydroxyl groups from crystallographic lattice. Differential images are proposed for the evaluation of water distribution in the pore spaces and values of porosity, directly related to the fluid removed after the drying of the sample. Porosity values for exemplary shale samples, calculated for differential results are consistent with the porosity obtained using T2 cut-offs. The relations between cation exchange capacity and T2 log-mean values for the samples at different saturation states are also shown.
      Graphical abstract image

      PubDate: 2017-06-17T04:17:03Z
      DOI: 10.1016/j.micromeso.2017.05.054
      Issue No: Vol. 252 (2017)
       
  • Pt-Ru nanoparticles functionalized mesoporous carbon nitride with tunable
           pore diameters for DMFC applications
    • Authors: M. Bello; S.M.Javaid Zaidi; Amir Al-Ahmed; Suddhasatwa Basu; Dae-Hwan Park; Kripal Singh Lakhi; Ajayan Vinu
      Pages: 50 - 58
      Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): M. Bello, S.M.Javaid Zaidi, Amir Al-Ahmed, Suddhasatwa Basu, Dae-Hwan Park, Kripal Singh Lakhi, Ajayan Vinu
      Mesoporous carbon nitrides (MCN) with different pore diameters are prepared by a nano-hard-templating strategy using SBA-15 with tunable pore diameters as templates through a simple polymerization of carbon tetrachloride (CTC) and ethylenediamine (EDA) as carbon and nitrogen precursors respectively. The prepared materials are functionalized with Pt and Ru nanoparticles in the highly ordered mesochannels which are separated by thick CN walls. The characterization results by XRD, HRSEM, FT-IR, and N2 adsorption reveal that the prepared MCN samples exhibit well-ordered porous structure and possess larger surface area and uniform pore diameter in comparison to other supports studied. MCN with different pore diameters are impregnated with Pt and Ru nanoparticles which are employed as electrodes for direct methanol fuel cells (DMFC). The performance of the Pt-Ru/MCN is compared with that of commercial MWCNT and Carbon Black-Vulcan-72 (CB-V-72). Among the materials studied, MCN-150(Pt-Ru) shows the highest catalytic activity of 65 mA/cm2, which outperforms Pt-Ru/C by more than 30% and has reasonable stability. The DMFC testing of the membrane electrode assembly of these catalysts reveal that the power density of the best catalyst, MCN-150(Pt-Ru) exceeds by more than two times that of the commercial anode catalyst.
      Graphical abstract image

      PubDate: 2017-06-17T04:17:03Z
      DOI: 10.1016/j.micromeso.2017.06.021
      Issue No: Vol. 252 (2017)
       
  • Effective adsorption/desorption of perchlorate from water using corn stalk
           based modified magnetic biopolymer ion exchange resin
    • Authors: Wen Song; Baoyu Gao; Yu Guo; Xing Xu; Qinyan Yue; Zhongfei Ren
      Pages: 59 - 68
      Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Wen Song, Baoyu Gao, Yu Guo, Xing Xu, Qinyan Yue, Zhongfei Ren
      In this work, a novel corn stalk based modified magnetic biopolymer ion exchange resin (CS-MAB) was prepared and used to remove perchlorate from aqueous solution. The physicochemical characteristics of CS-MAB were observed by SEM/EDS, BET, TEM, VSM, and XPS. The saturated magnetization and average pore diameter of CS-MAB were 3.82 emu/g and 4.83 nm. In adsorption batch experiments, the optimal adsorbent dosage and pH value for perchlorate removal are 1.0–1.5 g/L and 3.0–10.0. The adsorption kinetics fitted well with intraparticle-diffusion model in the first 90 min, and pseudo-second-order model in 90–360 min, which suggested that the potential mechanisms of perchlorate removal are physical adsorption and ion exchange reaction between ClO4 − and Cl-containing groups of CS-MAB. Based on the analysis of Langmuir model, the maximum adsorption capacities of CS-MAB are 119.05 mg/g, 126.58 mg/g and 178.57 mg/g at 20 °C, 30 °C and 40 °C, respectively. The column adsorption of perchlorate could be described well by Thomas model, and the co-existing ions would restrain the perchlorate adsorption by the order of SO4 2− > Cl− > NO3 −. Chemical and biological technologies both can be used to effectively regenerate CS-MAB with the efficiency of 70%–90%.
      Graphical abstract image

      PubDate: 2017-06-17T04:17:03Z
      DOI: 10.1016/j.micromeso.2017.06.019
      Issue No: Vol. 252 (2017)
       
  • Studies of the mechanical and extreme hydrothermal properties of periodic
           mesoporous silica and aluminosilica materials
    • Authors: Dayton G. Kizzire; Sonal Dey; Robert A. Mayanovic; Ridwan Sakidja; Kai Landskron; Manik Mandal; Zhongwu Wang; Mourad Benamara
      Pages: 69 - 78
      Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Dayton G. Kizzire, Sonal Dey, Robert A. Mayanovic, Ridwan Sakidja, Kai Landskron, Manik Mandal, Zhongwu Wang, Mourad Benamara
      In order to assess the suitability of mesoporous materials for applications in energy harvesting/storage processes occurring under extreme conditions, their mechanical, thermal and hydrothermal properties need to be fully investigated. In this study, the bulk mechanical and extreme hydrothermal properties of periodic mesoporous SBA-15 type silica and SBA-15 type aluminosilica (Al-SBA-15) were investigated using in situ small angle x-ray scattering (SAXS). In situ SAXS measurements were made on dry mesoporous SBA-15 silica and Al-SBA-15 aluminosilica samples as a function of pressure (at room temperature) to ∼ 12 GPa and on the same mesoporous materials under extreme hydrothermal conditions (to 255 °C and ∼114 MPa) using the diamond anvil cell (DAC). The analyses of the high-pressure SAXS data indicate that the mesoporous Al-SBA-15 aluminosilica has substantially greater bulk mechanical stability (isothermal bulk modulus κ = 34.7(4.5) GPa) than the mesoporous SBA-15 silica (κ = 12.0(3.0) GPa). Our molecular dynamics (MD) simulations are able to accurately model the bulk mechanical stability properties of mesoporous SBA-15 silica but underestimate the same properties of Al-SBA-15 aluminosilica. Analysis of the in situ SAXS data measured under extreme hydrothermal conditions indicates swelling of the pore walls due to water incorporation that is more significant in mesoporous Al-SBA-15 aluminosilica (∼2x) than in SBA-15 silica. In addition, the Al-SBA-15 aluminosilica clearly exhibits superior hydrothermal stability compared to SBA-15 silica under the extreme experimental temperature and pressure conditions.
      Graphical abstract image

      PubDate: 2017-06-17T04:17:03Z
      DOI: 10.1016/j.micromeso.2017.06.016
      Issue No: Vol. 252 (2017)
       
  • Synthesis of L-serine modified benzene bridged periodic mesoporous
           organosilica and its catalytic performance towards aldol condensations
    • Authors: Ward Huybrechts; Jeroen Lauwaert; Anton De Vylder; Myrjam Mertens; Gregor Mali; Joris W. Thybaut; Pascal Van Der Voort; Pegie Cool
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Ward Huybrechts, Jeroen Lauwaert, Anton De Vylder, Myrjam Mertens, Gregor Mali, Joris W. Thybaut, Pascal Van Der Voort, Pegie Cool
      Periodic mesoporous organosilica materials (PMOs) offer unique possibilities towards catalysis due to their high stability and tunable organic bridges. Moreover, the presence of the organic bridges make them, in comparison with the traditional silica materials, much more robust in an aqueous environment. As a result, these materials can be applied as catalysts for the valorization of biomass-based resources which are, typically, performed in the presence of water. In this work, we post-synthetically modified benzene bridged PMO with L-serine, thus obtaining a bifunctional PMO bearing a primary amine with an alcohol group on the β-carbon. The promoting effect of the alcohol, in combination with the amine as a base catalyst, is beneficial in the aldol condensation of acetone and 4-nitrobenzaldehyde. Thorough characterization, including a solid state NMR study, of the L-serine modified PMO was performed as well as a successful catalytic test in an aqueous environment. We obtained a TOF value of 1.61 × 10−4 ± 0.08 × 10−4 s−1 and a high selectivity towards the aldol product.
      Graphical abstract image

      PubDate: 2017-05-28T05:35:13Z
      DOI: 10.1016/j.micromeso.2017.05.034
      Issue No: Vol. 251 (2017)
       
  • Promotional effect of samarium on the activity and stability of Ni-SBA-15
           catalysts in dry reforming of methane
    • Authors: Zahra Taherian; Mardali Yousefpour; Mohammad Tajally; Behnam Khoshandam
      Pages: 9 - 18
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Zahra Taherian, Mardali Yousefpour, Mohammad Tajally, Behnam Khoshandam
      Samarium-promoted of 10 wt% Ni-SBA-15 catalysts, were prepared with various loadings of samarium (0.5, 1.5, 3 wt %), by two-solvent impregnation, which was known as a desired metal dispersion method for dry reforming of methane. The catalysts with/without promoter, were characterized by N2 adsorption-desorption, x-ray diffraction (low and high angles of XRD), x-ray fluorescence (XRF), high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), energy dispersive x-ray spectrometry (EDS), wavelength dispersive x-ray spectrometry (WDS), temperature programmed oxidation/reduction (TPO/TPR) techniques, and tested in dry reforming of methane (DRM). XRD and BET results indicated that by adding more than 0.5%wt of samarium, decreased the catalysts' surface area and particles size; and improved the activity and long term stability. Among these promoted catalysts, 3Sm-10Ni-SBA-15 showed the highest catalytic activity and stability. TEM and TPR analysis of 3Sm-10Ni-SBA-15 sample, revealed that addition of samarium enhanced the interaction of NiO particles with support, and promoted dispersion of NiO species. The TPO analysis revealed that the addition of 3 wt% samarium increased the amount of deposited coke, as well. Furthermore, FESEM and HRTEM images confirmed the formation of nanotubes carbon on the surface of spent catalysts.
      Graphical abstract image

      PubDate: 2017-06-02T13:23:34Z
      DOI: 10.1016/j.micromeso.2017.05.027
      Issue No: Vol. 251 (2017)
       
  • Probing into the mesoporous structure of carbon xerogels via the low-field
           NMR relaxometry of water and cyclohexane molecules
    • Authors: Calin Cadar; Cosmin Cotet; Lucian Baia; Lucian Barbu-Tudoran; Ioan Ardelean
      Pages: 19 - 25
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Calin Cadar, Cosmin Cotet, Lucian Baia, Lucian Barbu-Tudoran, Ioan Ardelean
      The liquid morphology of water and cyclohexane molecules, under partially saturated conditions inside the porous structure of two mesoporous carbon xerogels, was investigated using low-field nuclear magnetic resonance (NMR) relaxometry. The two xerogels were prepared under the same conditions, but with a different resorcinol-to-catalyst ratio. Two techniques were used in our investigations: the well-known Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence for transverse relaxation measurements and the Fast Field-Cycling (FFC) relaxometry technique for longitudinal relaxation dispersion measurements. It was found a stronger interaction of cyclohexane molecules with the pore surface as compared with water molecules. This leads to a uniform coverage of cyclohexane molecules on the pore surface for lower filling degrees while, in the case of water filled carbon xerogels, the distribution was non-uniform. Due to the stronger adsorption of cyclohexane molecules on the pore surface, it was possible to identify the micropores of the carbon xerogels predicted by nitrogen adsorption data. The NMR relaxation data have clearly demonstrated that, by increasing the resorcinol-to-catalyst ratio, the size of mesopores increases. Moreover, the enhanced adsorption affinity of carbon xerogels for cyclohexane shows that this type of materials can be employed as adsorbents for the removal of similar organic contaminants from water.
      Graphical abstract image

      PubDate: 2017-06-02T13:23:34Z
      DOI: 10.1016/j.micromeso.2017.05.033
      Issue No: Vol. 251 (2017)
       
  • Spinel-structured FeCo2O4 mesoporous nanosheets as efficient electrode for
           supercapacitor applications
    • Authors: Saad G. Mohamed; Sayed Y. Attia; Hamdy H. Hassan
      Pages: 26 - 33
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Saad G. Mohamed, Sayed Y. Attia, Hamdy H. Hassan
      Iron cobaltite (FeCo2O4) has been successfully prepared via a conventional facile solvothermal reaction, followed by a calcination step. The as-prepared material exhibits a 2D-nanosheets morphology, which expected to provide better electronic transportation as compared to zero-dimensional nanomaterials. FeCo2O4 nanosheets were tested as an electrode material for supercapacitor applications. The as-prepared material showed an excellent electrochemical performance on Ni foam substrate. It exhibited high charge storage property with a specific capacitance value of 853.8 F g−1 at 5 A g−1 and also a remarkable cycling stability with 87.5% capacitance retention being stable after 3000 cycles. It also showed a superior rate capability with (73%) from 5 to 25 A g−1. The excellent electrochemical performance of FeCo2O4 nanosheets is related to its high conductivity, high porosity, and the fast electrons/ions transportation.
      Graphical abstract image

      PubDate: 2017-06-02T13:23:34Z
      DOI: 10.1016/j.micromeso.2017.05.035
      Issue No: Vol. 251 (2017)
       
  • Formation of micro/mesopores during chemical activation in tailor-made
           nongraphitic carbons
    • Authors: Sang-Eun Chun; J.F. Whitacre
      Pages: 34 - 41
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Sang-Eun Chun, J.F. Whitacre
      The mechanism of chemical activation by potassium hydroxide (KOH) was studied in highly controlled non-graphitic carbon structures to explore the constituent reactions and the related pore formation processes involved in producing highly microporous activated materials. For this purpose, nongraphitic carbon was activated independently with intermediate species of either metallic potassium (K) or potassium carbonate (K2CO3) reduced from KOH (activating agent). Structural and morphological changes during activation were probed ex situ using X-ray diffractometry and Brunauer–Emmett–Teller (BET) nitrogen gas adsorption. Reduced K and K2CO3 disordered the stacking graphene layers to different extents. While micropore features were induced upon K evaporation following infiltration, the existing micropores were expanded into mesopores by K2CO3 gasification. Exclusive activation with K or K2CO3 induced ultra-small micropores, as measured using cyclic voltammetry. This work explains why activation using a KOH solution develops the preferable porous texture for use in many devices by creating open microporous structures as a result of the synergistic activation of both K and K2CO3.
      Graphical abstract image

      PubDate: 2017-06-02T13:23:34Z
      DOI: 10.1016/j.micromeso.2017.05.038
      Issue No: Vol. 251 (2017)
       
  • Sorption behaviors and relation between selectivity and possible cavity
           shapes of the molecularly imprinted materials
    • Authors: Hyun Min Lee; Sung Gyu Lee; Hye Ryoung Park; Sung Hyo Chough
      Pages: 42 - 50
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Hyun Min Lee, Sung Gyu Lee, Hye Ryoung Park, Sung Hyo Chough
      Molecular imprinted materials (MIP) were prepared through the phase inversion process after polymerization between sol-gel particles of triethoxy orthosilicate/3-(trimethoxysilyl)propyl methacrylate and mixture of styrene/acrylic acid. The sol-gel particles were rapidly precipitated by the addition of dilute NaCl solution. After removing NaCl and NH4OH, the precipitated sol-gel particles were polymerized with two different mixtures of styrene/acrylic acid (5/1 and 10/1 ratios) in dioxane to prepare the corresponding sol-gel composites, which differ in the average length of styrene segments in-between carboxyl groups. The composites dispersed in dioxane were adsorbed with template until completing the complexation with functional groups, and then MIPs were prepared through the phase inversion process by the addition of non-solvent, H2O. The relationship between the distribution of binding cavity shapes and the selectivity of MIP was considered depending on the length of styrene segments per one carboxyl group of MIP. The MIP of the longer styrene segment per one -COOH (10/1 of styrene/acrylic acid) showed higher selectivity than the shorter one (5/1 of styrene/acrylic acid). This can be explained by the higher proportion of the cavity shapes that surround completely template for the specific binding of the template. Langmuir isotherm described all the sorption data well suggesting that the sorption in these MIPs was mainly accomplished in monolayer. Scatchard analysis revealed that the sorption sites were heterogeneous for the template.
      Graphical abstract image

      PubDate: 2017-06-02T13:23:34Z
      DOI: 10.1016/j.micromeso.2017.05.028
      Issue No: Vol. 251 (2017)
       
  • Enhanced adsorption of rubidium ion by a phenol@MIL-101(Cr) composite
           material
    • Authors: Yaoyao Fang; Guihua Zhao; Wei Dai; Luying Ma; Na Ma
      Pages: 51 - 57
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Yaoyao Fang, Guihua Zhao, Wei Dai, Luying Ma, Na Ma
      A novel composite adsorbent, phenol@MIL-101(Cr), was prepared using MIL-101(Cr) functionalized with different amount of phenol via an impregnation technique. These new composite adsorbents were characterized by X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and N2 adsorption and the results showed that the phenol was immobilized in the MIL-101(Cr) structure. The adsorption performance of the composite for rubidium ions from aqueous solutions was evaluated by batch tests and using a fixed-bed breakthrough column at room temperature (25 °C). The phenol@MIL-101(Cr) exhibited high Rb+ uptake capacities, which are superior to all those previously reported in the literature. This excellent capacity is attributed to the exchange of acidic protons between the phenol groups and the rubidium ions. The saturated adsorbents were easily regenerated by washing with an ammonium nitrate solution. After regeneration, more than 90% of the rubidium ion capacity was maintained. Based on these results, MIL-101(Cr) modified by phenol should be a promising adsorbent for the separation and purification of rubidium ions from salt lakes.
      Graphical abstract image

      PubDate: 2017-06-02T13:23:34Z
      DOI: 10.1016/j.micromeso.2017.05.048
      Issue No: Vol. 251 (2017)
       
  • Precisely controlled encapsulation of Fe3O4 nanoparticles in mesoporous
           carbon nanodisk using iron based MOF precursor for effective dye removal
    • Authors: M. Angamuthu; G. Satishkumar; M.V. Landau
      Pages: 58 - 68
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): M. Angamuthu, G. Satishkumar, M.V. Landau
      A facile strategy developed for the fabrication of composite material comprising mesopores and representing an iron oxide core/encapsulated in carbon nanodisk shell using Fe-based MOF as precursor. Catalytic carbonization of Fe2+ coordinated 1,4,5,8 -naphthaleneteracarboxylic dianhydride MOF at 725 °C under N2 atmosphere followed by air treatment at 300 °C yielded Fe3O4 nanoparticles encapsulated in mesoporous carbon matrix (FeMCNA-300). The XRD and N2 adsorption studies confirm the presence of Fe3O4 nanoparticles and mesopores in the carbon matrix, respectively. MOF precursor generates mesopores of narrow pore size distribution without aid of structure directing agent in the carbon shell through straightforward catalytic reduction of core iron oxide. FeMCNA-300 demonstrated outstanding catalytic activity towards the degradation of 150 ppm of methylene blue (MB) dye in water with 84% TOC conversion in 15 min at room temperature. MB and oxidant H2O2 interact with iron oxide nanoparticles through confined mesoporous channel in the FeMCNA-300 carbon nanodisk. This permits the generated OH at the surface of magnetite nanoparticles to instantly oxidize the MB molecules adsorbed in the close proximity. FeMCNA-300 under ultra-sonication decolourise MB completely with high TOC conversion of about 84% at maximum iron leaching of 2% up to five successive recycles.
      Graphical abstract image

      PubDate: 2017-06-07T13:28:27Z
      DOI: 10.1016/j.micromeso.2017.05.045
      Issue No: Vol. 251 (2017)
       
  • Adsorptive desulfurization of fuels with Cu(I)/SBA-15 via low-temperature
           reduction
    • Authors: Liming Kong; Ting Zhang; Riyuan Yao; Yongping Zeng; Lili Zhang; Panming Jian
      Pages: 69 - 76
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Liming Kong, Ting Zhang, Riyuan Yao, Yongping Zeng, Lili Zhang, Panming Jian
      Cu+-modified SBA-15 mesoporous adsorbents (Cu(I)/SBA-15) were prepared via a low temperature reduction with diluted hydrazine hydrate aqueous solution as reduction agent. The samples were characterized by XRD, N2 adsorption-desorption isotherms, TEM, XPS, and H2-TPR. It was revealed that the amount and state of Cu+ species on SBA-15 was significantly affected by the reduction temperature. The Cu+ ratio of the total amount of copper species increased when the reduction temperature increased from 20 °C to 40 °C, the Cu+ species have a high dispersion on the SBA-15, and the mesoporous structure of SBA-15 still keeps intact. In contrast, when the reduction temperature was raised up to 50 °C, the Cu+ amount obviously decreased, some aggregated Cu2O formed on SBA-15, and the SBA-15 matrix suffered partial damage. The thiophene adsorption capacity on the Cu(I)/SBA-15(n) was measured, and the Cu(I)/SBA-15(40) shows a higher adsorption capacity than the other samples due to the high Cu+ ratio of the total amount of copper species (80.77%) in Cu(I)/SBA-15(40). The adsorption equilibrium data were described by the Langmuir isotherm models and the maximum adsorption capacity (qm) of thiophene adsorbed by Cu(I)/SBA-15(n) was calculated by Langmuir model.
      Graphical abstract image

      PubDate: 2017-06-07T13:28:27Z
      DOI: 10.1016/j.micromeso.2017.05.052
      Issue No: Vol. 251 (2017)
       
  • One-dimensional hierarchically porous carbon from biomass with high
           capacitance as supercapacitor materials
    • Authors: Chen Liang; Jinpeng Bao; Chunguang Li; He Huang; Cailing Chen; Yue Lou; Haiyan Lu; Haibo Lin; Zhan Shi; Shouhua Feng
      Pages: 77 - 82
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Chen Liang, Jinpeng Bao, Chunguang Li, He Huang, Cailing Chen, Yue Lou, Haiyan Lu, Haibo Lin, Zhan Shi, Shouhua Feng
      One-dimensional hierarchically porous carbon was prepared by carbonized and activated plant metaplexis and exhibited large surface area and high performance as supercapacitor electrode materials. Scanning electron microscope, transmission electrode microscope, X-ray spectroscopy, X-ray photoelectron spectroscopy, and Raman were used to characterize the microtopography and chemical composition of the materials as well as their transformation during the preparation process. With specific surface area (1394m2 g−1) and fine electrochemistry performance, the product exhibited a capacitance of 256.5 F g−1 at 5 mV s−1 and a very low equivalent series resistance of 0.16 Ω. The fine supercapacitor performance could be attributed to the hierarchically porous, large surface area and the specific ultralong tubular structure.
      Graphical abstract image

      PubDate: 2017-06-07T13:28:27Z
      DOI: 10.1016/j.micromeso.2017.05.044
      Issue No: Vol. 251 (2017)
       
  • Bis-chlorinated aromatics adsorption in Faujasites investigated by
           molecular simulation-influence of Na+ cation
    • Authors: J. Randrianandraina; I. Deroche; R. Stephan; M.-C. Hanf; Ph. Sonnet
      Pages: 83 - 93
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): J. Randrianandraina, I. Deroche, R. Stephan, M.-C. Hanf, Ph. Sonnet
      Molecular simulations have been employed in order to explore at the microscopic scale the adsorption of bis-chlorinated aromatics (1,2- and 1,3-dichlorobenzene) in Faujasite, a large pore openings zeolite. Both, the purely siliceous and the sodium cation exchanged forms of zeolite structures have been respectively considered, aiming to clearly determine the role of the charge compensating cation in the adsorption phenomenon of the investigated aromatics. A suited combination of classical and electronic structure simulation tools provided a clear overall picture of the adsorption process, from both local and global points of view, well matching with the accessible experimental data. The adsorbate preferential locations, adsorbate/zeolite interaction nature and geometry as well as the adsorption energy were extracted from Density Functional Theory calculations. Furthermore, on the basis of classical force fields, the Gibbs ensemble Monte Carlo simulations allowed predicting the room temperature (298 K) adsorption isotherms for the investigated molecules in Faujasite, within the purely siliceous and Na+ exchanged form, with mobile extra-framework cations upon the adsorption process. Finally, we accomplished a detailed analysis of the microscopic mechanism in play along the whole adsorption process, with a special highlight to the understanding of the interaction geometry of the molecule with the sodium cation, in function of its crystallographic site. Location of the charge compensating cation has been found to influence the nature of interaction with the adsorbate molecule.
      Graphical abstract image

      PubDate: 2017-06-07T13:28:27Z
      DOI: 10.1016/j.micromeso.2017.05.046
      Issue No: Vol. 251 (2017)
       
  • The effect of gaseous ammonia treatment of AM-6 crystallized in the
           presence of tetramethylammonium cations on their removal from the crystal
           pores, and the crystal quality and structure of AM-6
    • Authors: Rumeysa Tekin; Juliusz Warzywoda; Albert Sacco
      Pages: 94 - 104
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Rumeysa Tekin, Juliusz Warzywoda, Albert Sacco
      Vanadosilicate AM-6 products with different crystal quality (i.e., disorder, or average length of the V-O-V chains in the AM-6 framework), as determined from the FWHM of ∼868 cm−1 Raman band, but with identical crystallinity/long range order and purity, as determined from the XRD data, were hydrothermally synthesized from reaction mixtures with different molar compositions at 448–503 K using tetramethylammonium (TMA+) ions. The combined SEM, EDX, XRD, Raman, TGA, XPS, and nitrogen adsorption isotherm data showed that by treating these as-synthesized materials in gaseous ammonia at 673 K it is possible to completely remove TMA+ ions from the AM-6 pores without adversely affecting product crystallinity and the micropore structure of AM-6, and with only minimal degradation of crystal quality of the resulting products. However, the success in a complete removal of TMA+ ions without affecting other crystalochemical characteristics of the product depended on its initial crystal quality. TMA+ ions could not be completely removed from the lowest crystal quality product (FWHM = 20.3 cm−1) without completely decomposing the V-O-V chains. The intermediate crystal quality product (FWHM = 15.0 cm−1) could be successfully ammonia-treated only at 673 K to remove TMA+ ions, but higher temperatures resulted in a complete decomposition of the V-O-V chains. The highest crystal quality product (FWHM = 12.7 cm−1) retained the integrity of V-O-V chains as well as the long range order and the micropore structure when ammonia-treated up to 748 K.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.05.051
      Issue No: Vol. 251 (2017)
       
  • The impact of Si/Al ratio on properties of aluminosilicate aerogels
    • Authors: Anton S. Shalygin; Ivan V. Kozhevnikov; Evgeny Yu. Gerasimov; Andrey S. Andreev; Olga B. Lapina; Oleg N. Martyanov
      Pages: 105 - 113
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Anton S. Shalygin, Ivan V. Kozhevnikov, Evgeny Yu. Gerasimov, Andrey S. Andreev, Olga B. Lapina, Oleg N. Martyanov
      The Si/Al ratio is a key parameter of acid-base, structural, textural and, consequently, catalytic properties of amorphous crystalline (micro- and mesoporous) aluminosilicates. The changes of structural and textural characteristics of Al-Si aerogels with gradual increase of aluminum content are investigated. Aerogels were prepared via sol-gel method using prehydrolysed tetraethoxysilane and aluminium isopropoxide stabilized by acetylacetone. The gelation of the obtained sols took place in the presence of ammonia with the following drying in supercritical isopropanol. It was shown all aluminum reacts with prehydrolyzed tetraethoxysilane forming spherical particles in case the content of Al in the samples is less than 20 mol %. Aluminum drives the increase of interparticle coupling leading to the particle agglomeration, which is associated with the increase of the particle size and decrease of specific surface area and pore volume. For the samples with the aluminum content of >50 mol % the formation of pseudoboehmite plate-like particles is observed. The pseudoboehmite particles prevent the sintering of SiO2 particles that leads to the increase of the aerogel specific surface area and pore volume. In case the high aluminum content (>80 mol %) the silica particles serve as a connector between boehmite plates. The ratio between Brønsted and Lewis acid sites decreases gradually with the increase of aluminum content of the aluminosilicate aerogels.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.05.053
      Issue No: Vol. 251 (2017)
       
  • Microwave-assisted preparation of hollow porous carbon spheres and as
           anode of lithium-ion batteries
    • Authors: Shimei Zou; Xingyan Xu; Youqi Zhu; Chuanbao Cao
      Pages: 114 - 121
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Shimei Zou, Xingyan Xu, Youqi Zhu, Chuanbao Cao
      Amorphous and hollow porous carbon spheres are obtained by a microwave-assisted method. The as-prepared carbon spheres present good dispersion, homogeneous size, large pore volume and abundant micro/mesoporous shell. Different morphologies of the hollow carbon materials could be obtained by tuning the proportion of ethanol-water. The method is simple, time-saving and under mild reaction condition (low temperature and atmospheric pressure). When the as-prepared carbon spheres are used as anode of LIB, a discharge capacity of 1750 mA h g−1 is achieved at first cycle and still maintain 862 mA h g−1 after 100 cycles for HPC-3 at a current of 0.1 A g−1. The rate capability and cycle stability of HPC-3 are also excellent. The disordered and hierarchical porosity structure of hollow carbon spheres, which provide efficient active sites and convenient mass diffusion path, make the electrode superior electrochemical performances.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.05.062
      Issue No: Vol. 251 (2017)
       
  • A Brønsted acid functionalized periodic mesoporous organosilica and its
           application in catalytic condensation and THP protection/deprotection
           reactions
    • Authors: Björn Schäfgen; Oliver D. Malter; Elizeus Kaigarula; Axel Schüßler; Stefan Ernst; Werner R. Thiel
      Pages: 122 - 128
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Björn Schäfgen, Oliver D. Malter, Elizeus Kaigarula, Axel Schüßler, Stefan Ernst, Werner R. Thiel
      In this work we report the synthesis of a periodic mesoporous organosilica (PMO) derived from 1,4-bis(triethoxysilyl)benzene (BTEB) and its functionalization with propane sulphonic acid groups via the post synthetic grafting method according to modified procedures from the literature. The material contains an acid loading of approx. 0.50 mmol/g. Being applied in various catalytic reactions, it shows moderate to little activity in condensation reactions. In THP-protection of alcohols the material is highly efficient and superior to known silica supported sulphonic acid catalysts. The activity in the corresponding deprotection reaction is comparable to typical catalysts used in this field. In addition, the acidic PMO is recyclable without any loss of activity over three catalytic runs. The mesoporous material was thoroughly characterized by solid-state CP-MAS NMR to follow the functionalization process, powder XRD to show the 2D hexagonal structure that remains pristine through all modifications and BET measurements that show a high surface area between 1185 m2/g and 681 m2/g and a stable pore diameter of around 50 Å.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.05.047
      Issue No: Vol. 251 (2017)
       
  • Surface polarity estimation of metal-organic frameworks using liquid-phase
           mixture adsorption
    • Authors: Maria Sin; Christel Kutzscher; Irena Senkovska; Teng Ben; Shilun Qiu; Stefan Kaskel; Eike Brunner
      Pages: 129 - 134
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Maria Sin, Christel Kutzscher, Irena Senkovska, Teng Ben, Shilun Qiu, Stefan Kaskel, Eike Brunner
      A new methodology for surface polarity screening of MOFs is proposed based on quantitative 1H NMR spectroscopic measurements of liquid-phase adsorption. The influence of the surface polarity on the adsorption process was studied on several materials, e.g. activated carbons, PAF-1, MIL-101(Cr), HKUST-1, and a UiO-67-series. The surface polarity was characterized through the difference in the 1,4-dioxane adsorption uptake from two solvents of opposite polarity, namely n-heptane and N,N-dimethylformamide. An NMR-derived polarity index was defined where the polarity of the MOF corresponds to its affinity to polar substances. It is demonstrated that the structural modifications of MOF materials, which should affect the polarity of these MOFs, are indeed reflected by the polarity index.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.06.001
      Issue No: Vol. 251 (2017)
       
  • Preparation of multi-layer pervaporation membrane by electro-spraying of
           nano zeolite X
    • Authors: Farzaneh Asvadi; Ahmadreza Raisi; Abdolreza Aroujalian
      Pages: 135 - 145
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Farzaneh Asvadi, Ahmadreza Raisi, Abdolreza Aroujalian
      In this study, multi-layer nano zeolite X/polyvinyl alcohol (PVA)/polyethersulfone (PES) membrane was fabricated by electro-spraying of nano zeolite X particles on the dual-layer PVA/PES membrane that was prepared by the phase separation method. For this purpose, the surface of the PVA layer was modified by corona air plasma to increase the surface energy and adhesion of the inorganic layer. The SEM and FTIR tests were used to characterize the fabricated membranes. The membrane separation performance was evaluated for pervaporative dehydration of aqueous ethanol solutions. The effects of PVA and zeolite layers thickness and zeolite concentration on the separation performance of the multi-layer membranes were investigated. The results revealed that the total permeation flux and water separation factor decreased and increased, respectively by an increase in the PVA and zeolite layers thickness. Moreover, as the zeolite concentration varied from 2.5 to 5 %wt., the total flux reduced and the separation factor enhanced and a further increase in the zeolite concentration led to higher permeation flux and lower water separation factor. It was observed that the combination of the electro-spraying process and phase separation technique is an innovative alternative for the fabrication of nano-composite prevaporation membranes.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.05.060
      Issue No: Vol. 251 (2017)
       
  • Structure evolution of mesoporous silica under heavy ion irradiations of
           intermediate energies
    • Authors: Yu Lou; Sandrine Dourdain; Cyrielle Rey; Yves Serruys; David Simeone; Nicolas Mollard; Xavier Deschanels
      Pages: 146 - 154
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Yu Lou, Sandrine Dourdain, Cyrielle Rey, Yves Serruys, David Simeone, Nicolas Mollard, Xavier Deschanels
      Mesoporous sol-gel silica thin films were irradiated with gold ions of medium energies from 0.5 MeV to 12 MeV. In all cases these porous materials are compacted as a result of mesopore collapse and deformation. X-ray reflectivity and SEM measurement show that the total compaction (densification) is achieved for a fluence of about 2 × 1014 cm−2 (∼5 × 1021 keV cm−3). The process of mesoporosity collapse seems different according to the irradiation regime (nuclear versus electronic). This effect results in a U-shaped evolution of the curve of the damage cross section as a function of the energy of ions Au. Infrared measurement of Au 0.5 MeV irradiated samples show a shift of TO3 band towards lower wavenumber, related to Si-O-Si bond angle and Si-O bond length change. The sol-gel mesoporous and nonporous samples exhibit a delayed shift compared to thermal nonporous ones, which indicates that sol-gel materials are more radiation tolerant from this point of view. The sensitivity of these mesoporous structures to the damage caused by irradiation opens interesting prospects for obtaining self-conditioning materials.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.05.057
      Issue No: Vol. 251 (2017)
       
  • Crystal structures and gas adsorption behavior of new
           lanthanide-benzene-1,4-dicarboxylate frameworks
    • Authors: Kitt Panyarat; Sireenart Surinwong; Timothy J. Prior; Takumi Konno; Apinpus Rujiwatra
      Pages: 155 - 164
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Kitt Panyarat, Sireenart Surinwong, Timothy J. Prior, Takumi Konno, Apinpus Rujiwatra
      Six new lanthanide metal organic complexes, i.e. [La2(NO2-BDC)3(H2O)4] (1) [Ln(L)0.5(NO2-BDC) (H2O)]·3H2O (Ln = Eu (2), Tb (3), Dy (4) and Ho (5); L = BDC2− or BDC2−/NO2-BDC2-) and [Tm(NO2-BDC)1.5(H2O)]·H2O (6), have been synthesized using mixed ligands of benzene-1,4-dicarboxylic acid (H2BDC) and the in situ generated 2-nitro-benzene-1,4-dicarboxylic acid (NO2-BDC2-). Single crystal structures and topologies of the complexes are presented based on the single crystal X-ray diffraction and spectroscopic data. Whilst the structures of 1 and 6 contain negligible voids, the frameworks of 2–5 are microporous in nature and stable upon the removal of all the water molecules from the structures and thermal treatment to over 400 °C. Based on the study of 2, significant adsorption capacities for carbon dioxide (95 cm3·g−1 or 4.2 mmol·g−1) and hydrogen (79 cm3·g−1 or 4 mmol·g−1), as well as the remarkable stability of the framework upon the sorption/desorption experiments are revealed.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.06.003
      Issue No: Vol. 251 (2017)
       
  • Synthesis and characterization of tin, tin/aluminum, and tin/boron
           containing MFI zeolites
    • Authors: Meysam Shahami; Ross Ransom; Daniel F. Shantz
      Pages: 165 - 172
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Meysam Shahami, Ross Ransom, Daniel F. Shantz
      The synthesis and characterization of tin, tin/aluminum, and tin/boron containing MFI zeolites are reported. It is shown that tin uptake is high (near 100%) but decreases with the introduction of a second heteroatom. Additionally, the zeolite crystal size decreases and morphology changes with the introduction of a second heteroatom as evidenced by FE-SEM and XRD. UV-Vis confirms the tetrahedral framework coordination of tin within the zeolite and the absence of tin oxide clusters. Studies of methanol adsorption using in-situ IR spectroscopy indicate that tin-MFI sample with low tin contents possess lower acidity, and that tin/aluminum samples confirm aluminum within the zeolite through the presence of a Brönsted acid site. Comparison of spectra of adsorbed d-acetonitrile on the surface of these catalysts with the silicalite-1 is consistent with the tin centers in the framework possessing Lewis acidity.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.05.049
      Issue No: Vol. 251 (2017)
       
  • Oxazine containing molybdenum(VI)–oxodiperoxo complex immobilized on
           SBA-15 as highly active and selective catalyst in the oxidation of alkenes
           to epoxides under solvent-free conditions
    • Authors: Maryam Zare; Zeinab Moradi-Shoeili; Parvin Esmailpour; Serdar Akbayrak; Saim Özkar
      Pages: 173 - 180
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Maryam Zare, Zeinab Moradi-Shoeili, Parvin Esmailpour, Serdar Akbayrak, Saim Özkar
      Molybdenum(VI)–oxodiperoxo complex containing an oxazine ligand, ([MoO(O2)2(phox)], phox: 2-(2′-hydroxyphenyl)-5,6-dihydro-1,3-oxazine) was conveniently synthesized and immobilized onto chloro-functionalized mesoporous silica SBA-15 by covalent bonding between the chloropropyl group on the internal surface of the pores and the nitrogen atom of oxazine ligand yielding [MoO(O2)2(phox)]/SBA-15. The resulting material was characterized by FT-IR, TGA, XRD, SEM, TEM, EDX, ICP-AES, BET and UV–vis spectroscopy. The heterogeneous catalyst [MoO(O2)2(phox)]/SBA-15 was employed in the epoxidation of alkenes, exhibiting high catalytic performance and selectivity for epoxide similar to that of homogeneous catalyst, [MoO(O2)2(phox)] under solvent-free conditions. Finally, it was found that the heterogeneous catalyst had virtually no degree of leaching, which allowed its recyclability to nine cycles without loss of catalytic performance.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.06.002
      Issue No: Vol. 251 (2017)
       
  • Avoiding the mononuclear phagocyte system using human albumin for
           mesoporous silica nanoparticle system
    • Authors: Sofia Nascimento dos Santos; Sara Rhaissa Rezende Dos Reis; Leonardo Paredes Pires; Edward Helal-Neto; Félix Sancenón; Thereza Christina Barja-Fidalgo; Romulo Medina de Mattos; Luiz Eurico Nasciutti; Ramón Martínez-Máñez; Ralph Santos-Oliveira
      Pages: 181 - 189
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): Sofia Nascimento dos Santos, Sara Rhaissa Rezende Dos Reis, Leonardo Paredes Pires, Edward Helal-Neto, Félix Sancenón, Thereza Christina Barja-Fidalgo, Romulo Medina de Mattos, Luiz Eurico Nasciutti, Ramón Martínez-Máñez, Ralph Santos-Oliveira
      The mononuclear phagocytic system is a key participant determining the half-life of nanoparticles (NPs) in the bloodstream and influencing active targeting. Several strategies to extend the circulation time of nanoparticles and to reduce MPS (Mononuclear Phagocyte System) uptake have been developed so far. Here we evaluated the potential of albumin coated-mesoporous silica nanoparticles to overcome MPS clearance in a mouse model of endometrioses. We found that human albumin bath was able to reduce unspecific uptake by liver and spleen but reduced accumulation of NPs to endometriosis site. Our data suggest that although human albumin bath may help to overcome MPS clearance of NPs, it affects NPs uptake by the target site.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.06.005
      Issue No: Vol. 251 (2017)
       
  • Controlling the size and shape of Mg-MOF-74 crystals to optimise film
           synthesis on alumina substrates
    • Authors: James Campbell; Begum Tokay
      Pages: 190 - 199
      Abstract: Publication date: October 2017
      Source:Microporous and Mesoporous Materials, Volume 251
      Author(s): James Campbell, Begum Tokay
      Mg-MOF-74 is a metal organic framework with the highest CO2 adsorption capacity of any porous material. Therefore, it has been suggested for CO2 separations as both an adsorbent and incorporated into membranes. Design of the Mg-MOF-74 crystal morphology is important to expand the applicability of the material. In this paper one step synthesis of Mg-MOF-74 films has been achieved by controlling the Mg-MOF-74 crystal morphology. Results show that increasing the fraction of ethanol and water in the reaction solution relative to dimethyl formamide (DMF) increases the size of the crystals produced, while resulting in a subsequent drop in yield. By using solvent composition to control the Mg-MOF-74 crystal size and shape the synthesis of Mg-MOF-74 thin films was achieved in one step, without the need for seeding. Films could be produced as thin as 1 μm, ten times thinner than any other previous membranes in the M-MOF-74 series, in a fraction of the time (only 2.5 h). Thicker films (up to 14 μm) could also be produced by increasing the fraction of ethanol and water in reaction solution, offering a methodology by which the thickness of Mg-MOF-74 membranes can be controlled. Films were produced on porous tubular alumina supports, and single gas measurements were conducted resulting in a CO2 permeance of 7.4 × 10−7 mol m−2 s−1 Pa−1 and an ideal CO2/CH4 selectivity of 0.5.
      Graphical abstract image

      PubDate: 2017-06-12T13:34:56Z
      DOI: 10.1016/j.micromeso.2017.05.058
      Issue No: Vol. 251 (2017)
       
  • Synthesis of microfibrous-structured SS-fiber@beta composite by a
           seed-assisted dry-gel conversion method
    • Authors: Jia Ding; Pengjing Chen; Jian Zhu; Guofeng Zhao; Ye Liu; Yong Lu
      Pages: 1 - 8
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Jia Ding, Pengjing Chen, Jian Zhu, Guofeng Zhao, Ye Liu, Yong Lu
      Microfibrous-structured SS-fiber@beta composites are synthesized by coupling dip-coating method with a seed-assisted dry-gel conversion method. The beta crystals in zeolite shell are formed by growth on the surface of pre-added beta seeds and TEAOH-induced nucleus. One interesting point is that this approach is working highly effectively and efficiently even at high dry gel SiO2/Al2O3 ratio of 200 (corresponding to 207 in the beta zeolite shell). Such SS-fiber@beta composites show great potentials for the heat/mass transfer limited reactions due to their hierarchical porosity, small crystals, controllable acidity as well as our distinctive microfibrous-structured design.
      Graphical abstract image

      PubDate: 2017-05-13T07:32:02Z
      DOI: 10.1016/j.micromeso.2017.05.015
      Issue No: Vol. 250 (2017)
       
  • Preparation of microporous zeolites TiO2/SSZ-13 composite photocatalyst
           and its photocatalytic reactivity
    • Authors: Yuanhui Wang; Jieyu Chen; Xinrong Lei; Yujie Ren
      Pages: 9 - 17
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Yuanhui Wang, Jieyu Chen, Xinrong Lei, Yujie Ren
      Development of novel hybrid photocatalysts with high efficiency and durability for photocatalytic hydrogen generation is highly desired but still remains a grand challenge currently. In the present work, TiO2-doped microporous zeolite SSZ-13 with varying amounts of TiO2 were prepared using solid state dispersion (SSD) method, as photocatalysts for the evolution of photocatalytic degradation of methylene blue and H2 evolution under UV–vis irradiation. The incorporation of P25 into SSZ-13 zeolite significantly enhanced the photocatalytic activity for H2 evolution (reduction) and degradation of methylene blue (oxidation). And the most efficient photocatalyst was proven to 60%TiO2 loading, whose H2 generation (126.7 μmol/h) was profoundly enhanced for 3 times with respect to P25 (37.2 μmol/h) and degradation rate of methylene blue was 96% within 2.5 h. The photocatalysts were characterized by XRD, SEM, BET, UV–vis and PL. The results showed TiO2 were well dispersed on the surface of zeolite and the strong interaction between P25 and SSZ-13 zeolite, which improved significantly photocatalytic performance of P25. This study suggested the potential photocatalytic application of microporous zeolite SSZ-13 as a catalyst carrier.
      Graphical abstract image

      PubDate: 2017-05-13T07:32:02Z
      DOI: 10.1016/j.micromeso.2017.05.011
      Issue No: Vol. 250 (2017)
       
  • Batch-scale preparation of hollow fiber supported CHA zeolite membranes
           and module for solvents dehydration
    • Authors: Ji Jiang; Xuerui Wang; Li Peng; Xiaolei Wang; Xuehong Gu
      Pages: 18 - 26
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Ji Jiang, Xuerui Wang, Li Peng, Xiaolei Wang, Xuehong Gu
      CHA zeolite membranes have been successfully synthesized on thin yttria-stabilized zirconia (YSZ) hollow fiber (HF) substrates by secondary growth method. Prior to membrane synthesis, the outer surface of YSZ hollow fibers were planted with ball-milled submicron CHA zeolite seeds. Extensive investigations on batch-scale preparation of CHA zeolite membranes were carried out in terms of seeding method. Uniform and continuous seed layers were achieved by vacuum seeding with the addition of colloidal silica in seed suspension, which resulted in high reproducibility HF CHA zeolite membranes at crystallization temperature of 160 °C for 20 h. The membranes showed average water permeation flux of ca. 8.0 kg m−2 h−1 with separation factor of ca. 2500 in 90 wt% ethanol/water mixture at 75 °C. A HF CHA zeolite membrane module was fabricated for multi-cycle dehydration of iso-propanol/water mixture and acetic acid/isopropanol/water mixtures at 75 °C with high stability for over 100 h.
      Graphical abstract image

      PubDate: 2017-05-13T07:32:02Z
      DOI: 10.1016/j.micromeso.2017.05.013
      Issue No: Vol. 250 (2017)
       
  • Graphene decorated with metal nanoparticles: Hydrogen sorption and related
           artefacts
    • Authors: Alexey Klechikov; Jinhua Sun; Guangzhi Hu; Mingbo Zheng; Thomas Wågberg; Alexandr V. Talyzin
      Pages: 27 - 34
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Alexey Klechikov, Jinhua Sun, Guangzhi Hu, Mingbo Zheng, Thomas Wågberg, Alexandr V. Talyzin
      Hydrogen sorption by reduced graphene oxides (r-GO) is not found to increase after decoration with Pd and Pt nanoparticles. Treatments of metal decorated samples using annealing under hydrogen or air were tested as a method to create additional pores by effects of r-GO etching around nanoparticles. Increase of Specific Surface Area (SSA) was observed for some air annealed r-GO samples. However, the same treatments applied to activated r-GO samples with microporous nature and higher surface area result in breakup of structure and dramatic decrease of SSA. Our experiments have not revealed effects which could be attributed to spillover in hydrogen sorption on Pd or Pt decorated graphene. However, we report irreversible chemisorption of hydrogen for some samples which can be mistakenly assigned to spillover if the experiments are incomplete.
      Graphical abstract image

      PubDate: 2017-05-13T07:32:02Z
      DOI: 10.1016/j.micromeso.2017.05.014
      Issue No: Vol. 250 (2017)
       
  • Effect of the well-designed functional groups and defects of porous carbon
           spheres on the catalytic oxidation performance
    • Authors: Weiliang Han; Yinshuang Zhao; Fang Dong; Guodong Zhang; Gongxuan Lu; Zhicheng Tang
      Pages: 35 - 42
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Weiliang Han, Yinshuang Zhao, Fang Dong, Guodong Zhang, Gongxuan Lu, Zhicheng Tang
      The oxygen functional groups and defects of carbon material played an important role in dispersion of active components and additives, reduction of Ce4+, etc. The reduction of Ce4+ and structure defects would increase surface oxygen concentration and oxygen vacancies. The dispersion of active components and additives, surface oxygen concentration and structure defects were key factor on CO oxidation. The oxygen functional groups and structure defects of porous carbon spheres (PCSs) increased by O3 treatment method. The effects of O3 treatment concentration on structures, properties of PCSs support and Pd-Ce/PCSs were investigated in detail. The particle size of PCSs had not been changed basically after O3 treatment. However, the outer of PCSs became uneven, which was main reason of the external surface area increase. The content of surface Pd4+, surface adsorption oxygen concentration, oxygen vacancies, defects, increased with increasing O3 treatment concentration. Relationship between the functional groups, defects of porous carbon spheres and their catalytic performance was investigated in detail. CO oxidation test showed that the Pd-Ce based catalysts supported by the PCSs after O3 treatment concentration for 45 mgL−1 had the best activity. The effect of moisture on CO conversion was explored, and the catalysts showed excellent stability under moisture condition.
      Graphical abstract image

      PubDate: 2017-05-13T07:32:02Z
      DOI: 10.1016/j.micromeso.2017.05.004
      Issue No: Vol. 250 (2017)
       
  • Facile synthesis of nano-sized hollow ZSM-5 zeolites with rich mesopores
           in shell
    • Authors: Tingjun Fu; Ruiyue Qi; Xia Wang; Weili Wan; Zhong Li
      Pages: 43 - 46
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Tingjun Fu, Ruiyue Qi, Xia Wang, Weili Wan, Zhong Li
      A hollow nano-ZSM-5 zeolites with mesoporous shell was successfully synthesized by a two-step alkaline treatment method. Firstly, nano-ZSM-5 zeolite was alkali treated with NaOH solution to dissolve internal silica of crystals and then the hollow structure was formed. After that, obvious mesopores were introduced in the shell of the hollow zeolites by a NaOH&TPAOH leaching based on the protective desilication. As a result, the external surface area was increased from 98 to 203 m2g-1, more than twice that of the untreated nano-ZSM-5. The thin shell and rich mesopores would improve its catalytic performance in many diffusion-limited reactions.
      Graphical abstract image

      PubDate: 2017-05-18T01:23:50Z
      DOI: 10.1016/j.micromeso.2017.05.021
      Issue No: Vol. 250 (2017)
       
  • Renewable aromatic production through hydrodeoxygenation of model bio-oil
           over mesoporous Ni/SBA-15 and Co/SBA-15
    • Authors: Yongxing Yang; Guangqiang Lv; Liangliang Deng; Boqiong Lu; Jinlong Li; Jiaojiao Zhang; Junyan Shi; Sujun Du
      Pages: 47 - 54
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Yongxing Yang, Guangqiang Lv, Liangliang Deng, Boqiong Lu, Jinlong Li, Jiaojiao Zhang, Junyan Shi, Sujun Du
      In present work, ordered mesoporous material SBA-15 was synthesized and used as the support for the dispersion of the nickel and cobalt active metal. XRD, N2 sorption, ICP, H2-TPR and TEM techniques were used for the Ni/SBA-15 and Co/SBA-15 catalysts characterization. Both Ni/SBA-15 and Co/SBA-15 catalysts were tested for the hydrogenation of the typical oxygen-containing molecule present in bio-oil in order to produce the renewable aromatic. Ni/SBA-15 catalyst exhibit much higher catalytic performance as compared with Co/SBA-15 catalyst for the hydrodeoxygenation reaction performance of anisole, but it is also obvious that the Ni/SBA-15 catalyst would inevitably lead to the emergence of partial hydrodeoxygenation product methoxycyclohexane. On the contrary, the direct hydrogenolysis of methoxy-functional group from anisole molecule could prevail over the Co/SBA-15, leading to much higher aromatic selectivity over the Co/SBA-15. Co/SBA-15 could selectively hydrogenolyse the CO bond and could act as the potential hydrodeoxygenation catalyst for aromatic production from the bio-oils because of its high efficiency in the removal of oxygen by a direct hydrogenolysis route.
      Graphical abstract image

      PubDate: 2017-05-18T01:23:50Z
      DOI: 10.1016/j.micromeso.2017.05.022
      Issue No: Vol. 250 (2017)
       
  • Influence of the mesopore's diameter on the freezing kinetics of water
    • Authors: Marcin Koniorczyk; Dalia Bednarska
      Pages: 55 - 64
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Marcin Koniorczyk, Dalia Bednarska
      The manuscript considers the kinetics of water freezing in mesopores of three silica gels with the dominant pore diameter is equal to 3 nm, 6 nm and 15 nm analysed using differential scanning calorimetry. We test four cooling rates: 2.5 °C/min; 5.0 °C/min; 7.5 °C/min and 10.0 °C/min. By integrating DSC signal we determine the relation between ice content and temperature. It appears that the process rate depends only on the temperature and the extent of conversion. The isoconversional method is used to select most suitable kinetic model. The Šesták-Berggren model gives the best approximation of the conversion function. The activation energy obtained using Starink method is smaller than using Friedman method for all silica gels under investigation. The pre-exponential factor and reaction orders are estimated using the procedure introduced by Málek and depend on the mesopore diameter. We prove that the results obtained using the Šesták-Berggren model are in good agreement with the experimental data for all investigated cases. Additionally, the SEM and nitrogen adsorption/desorption tests are performed to analyse the influence of cyclic inpore water freezing on the silica gels microstructure.
      Graphical abstract image

      PubDate: 2017-05-18T01:23:50Z
      DOI: 10.1016/j.micromeso.2017.05.012
      Issue No: Vol. 250 (2017)
       
  • Ethane Oxidative Dehydrogenation over ternary and binary mixtures of
           alkaline and alkaline earth chlorides supported on zeolites
    • Authors: Faouzi Ayari; Rania Charrad; Esther Asedegbega–Nieto; Mourad Mhamdi; Gérard Delahay; Farhat Farhat; Abdelhamid Ghorbel
      Pages: 65 - 71
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Faouzi Ayari, Rania Charrad, Esther Asedegbega–Nieto, Mourad Mhamdi, Gérard Delahay, Farhat Farhat, Abdelhamid Ghorbel
      Ethane Oxidative Dehydrogenation (ODH) into ethylene was successfully catalyzed by binary RbCl/MgCl2 and ternary NaCl/KCl/MgCl2 mixtures (with the eutectic composition) supported over lanthanum exchanged Na–Y zeolite. At 500 °C, both catalysts exhibited 100% selectivity towards ethylene at 40 and 20% ethane conversion for the binary and ternary mixtures, respectively. According to nitrogen physisorption results, the ternary mixture supported over Ultra stable zeolite led to inefficient catalyst due to the diffusion of melt throughout the zeolite cavities, while the use of MgO–like support should be avoided on the basis of XRD results. For binary mixtures, the size of the alkaline atom influences the melt mobility and therefore the catalytic activity. In this context, large sized atoms, like cesium, and small atoms, like sodium should be avoided. In fact, CsCl/MgCl2 binary mixture exhibited higher eutectic temperature (491 °C) and the corresponding catalyst is low in activity, while NaCl/MgCl2 does not behave like a binary mixture in the presence of zeolite on the basis of thermal analysis results. The presence of rare earths cations, namely bare La3+ (unreduced by hydrogen in TPR) obtained from lanthanum chloride, and Tb4O7 (reduced under hydrogen at 433 °C) issued from terbium nitrate, improved the catalytic activity.
      Graphical abstract image

      PubDate: 2017-05-18T01:23:50Z
      DOI: 10.1016/j.micromeso.2017.05.010
      Issue No: Vol. 250 (2017)
       
  • Dual-function hydrotalcite-derived adsorbents with sulfur storage
           properties: Dyes and hydrotalcite fate in adsorption-regeneration cycles
    • Authors: Wojciech Stawiński; Agnieszka Węgrzyn; Olga Freitas; Lucjan Chmielarz; Sónia Figueiredo
      Pages: 72 - 87
      Abstract: Publication date: 15 September 2017
      Source:Microporous and Mesoporous Materials, Volume 250
      Author(s): Wojciech Stawiński, Agnieszka Węgrzyn, Olga Freitas, Lucjan Chmielarz, Sónia Figueiredo
      Thermal treatment of hydrotalcite at increasing temperatures resulted in formation of mixed oxides that exhibited different adsorption behavior toward anionic and cationic industrial dyes. The material annealed at 450 °C was characterized by the highest maximum adsorption capacity for both types of dyes. The adsorption was strongly pH dependent and for the anionic dye abatement low pH was favored whilst higher pH was more preferable for removal of the cationic dye. According to the equilibrium experiments, the maximum adsorption capacity increased from 179 ± 5 to 291 ± 8 mg g−1 in case of the anionic dye at pH 3.5 and from 6 ± 2 to 48 ± 2 mg g−1 in case of the cationic dye at pH 8.0, on starting and thermally treated material at 450 °C, respectively. Detailed characteristics of spent adsorbent and its reconstructed form revealed that after each cycle of adsorption and thermal regeneration the maximum adsorption capacity of the material decreased due to changes in the structure and accumulation of sulfur compounds. Evolution of specific surface area and porosity was correlated with annealing temperatures and behavior of dye's residues.
      Graphical abstract image

      PubDate: 2017-05-23T05:29:13Z
      DOI: 10.1016/j.micromeso.2017.05.017
      Issue No: Vol. 250 (2017)
       
  • Zeolite supported palladium catalysts for hydroalkylation of phenolic
           model compounds
    • Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Uliana Akhmetzyanova, Maksym Opanasenko, Jan Horáček, Erica Montanari, Jiří Čejka, Oleg Kikhtyanin
      Bifunctional palladium-based catalysts with zeolite supports were investigated in phenol hydroalkylation, representing high-potential model reaction for transformation of lignocellulose-derived compounds to automotive and jet fuels. Conversion of phenol correlated with the amount of accessible acid sites and textural properties of the solid acid support: under the same reaction conditions and at the same Pd loading. The highest phenol conversions (99–100%) were obtained for large-pore zeolite Beta and mesopore-containing MCM-36/56 materials. The selectivity towards the targeted cyclohexylcyclohexane on different supports decreased in the following order Beta (57%) > MCM-36 (42%) ≈ MCM-56 (37%) > MCM-22 (20%), while the contribution of undesired reaction termination through formation of non-reactive cyclohexane was more pronounced for the expanded MCM-36/56 based catalysts. Substrate consumption after 60 min over the least active MCM-22-based catalysts increased with increasing Pd content as follows 27% (0.3 wt % Pd), 80% (0.5 wt % Pd) and 98% (0.7 wt % Pd). High activity of Pd/Beta catalysts was not vitiated even by sintering effects being the most pronounced for Beta as a support.
      Graphical abstract image

      PubDate: 2017-06-22T04:25:17Z
       
  • Enhancing adsorption property of Engelhard Titanosilicate-10 through
           incorporation of graphene oxide
    • Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Sing Yew Nguang, Suzanna Rosli Wong, Jia Sheng Law, Li Chien Khoo, Weng Hoong Lam, Eng Seng Chan, Pak Yan Moh
      Engelhard Titanosilicate-10 (ETS-10) has been studied widely for its adsorption and photocatalytic properties. The properties can be enhanced through various chemical approaches, such as modification of ETS-10 active sites with transition metal. In this work, graphene oxide incorporated ETS-10 (as GO/ETS-10) was prepared by refluxing the ETS-10 powder and GO suspension in water medium. The obtained GO/ETS-10, as revealed by X-ray photoelectron spectroscopy (XPS), was chemically bound through the carbon atoms of GO and the oxygen atoms on the surface of ETS-10. The GO/ETS-10 composite has shown exceptional adsorption properties towards cationic methylene blue (MB) in comparison to ETS-10 alone. However, results have shown that the GO/ETS-10 has poor adsorption affinity towards anionic methyl orange (MO) in water. The adsorption isotherms of GO/ETS-10 composite towards MB was best fitted to the Langmuir isotherm with maximum adsorption capacity of 286 mg·g− 1 which was about 2 times higher than adsorption capacity of ETS-10 alone, i.e. 135 mg·g− 1. Besides, adsorption kinetics of GO/ETS-10 was best fitted to the pseudo-second order model revealing that the chemisorption was dominant throughout the adsorption process. Considering the nature of GO/ETS-10 that is composed from less harmful elements, it has good potential in the environment remediation, such as water and air purification, with a good selectivity towards cationic molecules.
      Graphical abstract image

      PubDate: 2017-06-22T04:25:17Z
       
  • Continuous-flow chemoselective reduction of cyclohexanone in a monolithic
           silica-supported Zr(OPri)4 multichannel microreactor
    • Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Agnieszka Ciemięga, Katarzyna Maresz, Julita Mrowiec-Białoń
      Meerwein-Ponndorf-Vereley reduction of cyclohexanone using 2-butanol as hydrogen donor was studied in the multichannel monolithic silica microreactors modified with zirconium species to demonstrate their higher efficacy than of conventional batch systems with powdered catalysts. Zr(OPri)4 species were attached onto the monoliths siliceous surface to obtain a nominal Zr/Si mass ratio in the range of 0.01–0.28. The value of 0.14 gave the largest concentration of Lewis acid sites and hence also the highest conversion (88%) after 20 min reaction/residence time and productivity of 2.22 mmol/g h. The monoliths prepared by the sol-gel process combined with phase separation were characterized using nitrogen adsorption, mercury porosimetry, thermogravimetry, SEM, FTIR and UV–Vis spectroscopy, pyridine adsorption and XRD. They featured very open 3D co-continuous structure of 20 nm textural meso- and flow-through macropores 30–60 μm in diameter (4 cm3/g total pore volume) which was not appreciably changed after their modification with zirconium species. Diffraction peaks characteristic for crystalline zirconia were not detected even in materials with the highest Zr content.
      Graphical abstract image

      PubDate: 2017-06-22T04:25:17Z
       
  • Seed-assisted synthesis of ZSM-23 zeolites in the absence of alkali metal
           ions
    • Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Yujing Chen, Chuang Li, Lei Wang, Miao Zhang, Changhai Liang
      The seed-assisted synthesis of ZSM-23 zeolite in the absence of alkali metal ions (denoted as SNNa) was investigated. Highly crystallized SNNa with needle-shape morphology and size of 500–1100 nm in length and 50–200 nm in diameter can be synthesized. Much attention was paid to the roles of alkali metal ions during the crystallization process. The absence of Na+ can effectively avoid the impurity-quartz formation and promote SNNa crystallization in a broad range of SiO2/Al2O3 ratio between 80 and 200, whereas the crystallization rate was slowed down at the same time. On the contrary, the presence of Na+ had a significant effect both on the nucleation and crystal growth processes. The bifunctional catalyst Pt/H-SNNa prepared, showed good catalytic performance in the hydroisomerization of n-hexadecane due to its small crystal size, appropriate acidity and acid site distribution.
      Graphical abstract image

      PubDate: 2017-06-22T04:25:17Z
       
  • Microporous carbon spheres derived from resorcinol-formaldehyde solutions.
           A new approach to coat supports
    • Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Natalia Rey-Raap, Sara F. Villanueva, J. Angel Menéndez, Ana Arenillas
      Microporous carbon spheres of different morphology and porosity were synthesized from resorcinol-formaldehyde solutions by a simple and fast procedure. Polymeric spheres were shaped by means of microwave heating. Carbonization and activation with carbon dioxide were then applied to obtain the intended final carbon spheres. The influence of the pH, heating time and thermal treatments on the morphology and porosity of the carbon spheres was investigated. It was found that the size of the spheres, can be easily controlled during the synthesis process, specifically by modifying the pH of the precursor solution. An increase in the pH value from 3 to 5 led to carbon spheres with sizes of 4 μm and 3.5 μm, respectively, whereas time seemed to have no effect. These results have been attributed to the chemical mechanisms of the polymerization reaction. On the other hand, microporosity was tailored during the thermal treatments. Carbon spheres with surface areas of 630 m2/g and 1500 m2/g were obtained by applying carbonization and physical activation, respectively. Furthermore, the synthesis method proposed allows to obtained liquid polymerized inks that can be further used to coat ceramic supports by a simple spray-drying process, which enhances the potential of these materials for several applications.
      Graphical abstract image

      PubDate: 2017-06-22T04:25:17Z
       
  • Computer simulations of the structure and properties of organic pillared
           MFI zeolite catalyst
    • Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Baoyu Liu, Huiyong Chen, Su Cheun Oh, Yanxiong Fang
      Multifunctional porous hybrid materials have recently received a lot of attentions because they combine the advantages of incorporating both inorganic oxides and organic species into the structure to solve the limitation of sole component material. This paper reports a type of model of organic pillared MFI zeolite catalyst, in which the full-atom mimetic model is constructed by using molecular modeling technique. Dreiding force field is used to calculate the interactions between sorbate–sorbate and sorbate–sorbent in the organic pillared MFI zeolite. The optimized model is characterized by calculating low-angle and high-angle X-ray diffraction patterns. Besides, the adsorption behavior of benzene and toluene is also investigated through the mimetic model. Simulated adsorption isotherms of benzene and toluene are agreement with the experimental data at low pressure. Density distributions of benzene and toluene show that toluene adsorbs preferentially in the region of interlayer space of lamellar MFI zeolite while benzene tends to adsorb in the area of micropores at low pressure. With increasing pressure, the guest molecules gradually fill in the area of micropores and mesopores of the organic pillared MFI zeolite. Moreover, the developed strategy in the present work can be applied to build other model for organic pillared zeolite catalyst by arranging different zeolite frameworks or organic species.
      Graphical abstract image

      PubDate: 2017-06-22T04:25:17Z
       
  • Adsorption of 5-fluorouracil, hydroxyurea and mercaptopurine drugs on
           zeolitic imidazolate frameworks (ZIF-7, ZIF-8 and ZIF-9)
    • Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Maryam Gomar, Saeid Yeganegi
      A series of bio-compatible zeolitic imidazolate frameworks (ZIF-7, ZIF-8 and ZIF-9) have been studied as potential carriers for drug delivery applications. Grand canonical Monte Carlo (GCMC) simulations were performed to study the adsorption of three anti-cancer drugs namely 5-Fluorouracil, Hydroxyurea and Mercaptopurine. Adsorption isotherms, snapshots and energy of adsorption were used to analyze the drug delivery process. Our GCMC simulations revealed the high capacities of studied ZIFs (0.65–0.68 g/g) for the adsorption of 5-Fluorouracil and Hydroxyurea. ZIF-8 showed high capacity (0.55 g/g) for the adsorption of Mercaptopurine, while the adsorption capacity of ZIF-7 and ZIF-9 for Mercaptopurine were moderate (about 0.36–0.44 g/g). The high heat of adsorption (115–133 kJ/mol for 5-Fluorouracil in ZIF-8 and 200–240 kJ/mol for Mercaptopurine in three ZIFs) also suggests a controlled release process. The analysis of snapshots and radial distribution functions (RDFs) showed that the adsorption of drugs occurred preferentially in the 6-membered pores of ZIFs.
      Graphical abstract image

      PubDate: 2017-06-22T04:25:17Z
       
  • Ionic liquid and ethyl-based bifunctional ordered nanoporous organosilica
           supported palladium: An efficient catalyst for homo-coupling of
           phenylacetylenes
    • Abstract: Publication date: 1 November 2017
      Source:Microporous and Mesoporous Materials, Volume 252
      Author(s): Dawood Elhamifar, Afrooz Eram, Ramin Moshkelgosha
      A novel bifunctional ordered nanoporous organosilica with ethyl and ionic liquid framework supported palladium (Pd@ILEt-BNOS) is prepared, characterized and its catalytic performance in the homo-coupling of phenylacetylenes is developed. The Pd@ILEt-BNOS was prepared via simultaneous hydrolysis and condensation of bis(triethoxysilyl)ethane and alkyl-imidazolium ionic liquid in the presence of structure directing agent followed by treatment with palladium acetate. This nanostructure was characterized using transmission electron microscopy (TEM), nitrogen adsorption-desorption analysis, scanning electron microscopy (SEM), low angle X-ray diffraction (LAXRD), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, thermal gravimetric analysis (TGA) and energy dispersive X-ray (EDX) analysis. The Pd@ILEt-BNOS was successfully applied as efficient catalyst in the homo-coupling of phenylacetylenes and gave corresponding products in excellent yield. This was recovered and reapplied seven times without importance decrease in its efficiency. The life-time and stability of the catalyst were also investigated under applied conditions.
      Graphical abstract image

      PubDate: 2017-06-22T04:25:17Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.196.127.58
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016