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Journal Cover Microporous and Mesoporous Materials
  [SJR: 1.243]   [H-I: 116]   [6 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1387-1811
   Published by Elsevier Homepage  [3040 journals]
  • Synthesis of ordered mesoporous TiO2-Carbon-CNTs nanocomposite and its
           efficient photoelectrocatalytic methanol oxidation performance
    • Authors: Xiaoli Fan; Tao Wang; Yunxia Guo; Hao Gong; Hairong Xue; Hu Guo; Bin Gao; Jianping He
      Pages: 1 - 8
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Xiaoli Fan, Tao Wang, Yunxia Guo, Hao Gong, Hairong Xue, Hu Guo, Bin Gao, Jianping He
      Exploiting novel photoelectrocatalytic system for methanol fuel cell is of huge interest. Herein, we report a composite with carbon nanotubes (CNTs) embedded in the skeleton of ordered mesoporous TiO2-Carbon as a high-performance catalyst support for methanol oxidation under light irradiation. XRD, TEM and HR-TEM were employed to characterize the composite. Through the optimization of component proportion as well as calcination temperature, the TiO2-Carbon-CNTs nanocomposite with the CNTs content being 3.0 wt% and calcined temperature at 700 °C exhibited the best photoelectric property. A highest photocurrent density of 0.88 mA cm−2 on TiO2-Carbon-CNTs is obtained, which is times higher than that of sample without CNTs. The resulting Pt/TiO2-Carbon-CNTs films exhibit superior methanol oxidation performance. The enhanced charge transfer abilities and the synergetic effects between Pt and photointroduced holes on methanol oxidation contribute to the superior photoelectric performance.
      Graphical abstract image

      PubDate: 2016-11-12T09:01:21Z
      DOI: 10.1016/j.micromeso.2016.10.049
      Issue No: Vol. 240 (2016)
       
  • MCM-41 modified with transition metals by template ion-exchange method as
           catalysts for selective catalytic oxidation of ammonia to dinitrogen
    • Authors: Andrzej Kowalczyk; Aleksandra Borcuch; Marek Michalik; Małgorzata Rutkowska; Barbara Gil; Zbigniew Sojka; Paulina Indyka; Lucjan Chmielarz
      Pages: 9 - 21
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Andrzej Kowalczyk, Aleksandra Borcuch, Marek Michalik, Małgorzata Rutkowska, Barbara Gil, Zbigniew Sojka, Paulina Indyka, Lucjan Chmielarz
      Copper, iron and manganese were deposited on MCM-41 using template ion-exchange (TIE) method. Methanol solutions of CuCl2, FeCl2 and MnCl2 were used as precursors of deposited transition metal species. It was shown that introduction of transition metals into MCM-41 by TIE method resulted in deposition of iron and manganese in the form of highly dispersed species (mainly monomeric cations), while in case of copper also CuO crystallites were formed. Such aggregated copper oxide species were not detected in the samples of MCM-41 containing both copper and iron as well as copper and manganese. MCM-41 modified with transition metals by TIE method were found to be active catalysts for the process of the selective oxidation of NH3 to N2 (NH3-SCO), however catalytic performance of the studied samples strongly depended on the type of deposited metal. The samples modified with iron and manganese effectively catalyzed ammonia oxidation to dinitrogen only in the high temperature range. On the other side MCM-41 modified with copper was catalytically active at significantly lower temperatures, however selectivity to dinitrogen decreased at elevated temperatures. It was shown that simultaneous incorporation of copper and iron as well as copper and manganese resulted in the catalysts for the low-temperature NH3-SCO with significantly increased selectivity to dinitrogen in comparison to the monometallic copper containing catalyst.
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      PubDate: 2016-11-12T09:01:21Z
      DOI: 10.1016/j.micromeso.2016.11.002
      Issue No: Vol. 240 (2016)
       
  • Hierarchical architectures of ZSM-5 nanocrystalline aggregates with
           particular catalysis for lager molecule reaction
    • Authors: Yan Wang; Jinghong Ma; Fenfen Ren; Jun Du; Ruifeng Li
      Pages: 22 - 30
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Yan Wang, Jinghong Ma, Fenfen Ren, Jun Du, Ruifeng Li
      The spherical self-assemblies of ZSM-5 nanocrystals were hydrothermally synthesized by using organo-functionalized mesoporous silica (MS) as silica source. The prepared materials were well characterized by XRD, FTIR of framework vibration, SEM, TEM, N2 adsorption/desorption and TG analyses, to reveal their hierarchical architectures. The ZSM-5 nano-aggregates are composed of size-tunable nanocrystals, and the size and different morphologies of nanocrystals changed significantly from silanized MS rather than unsilanized MS. Spontaneously stacking of nanocrystals in the zeolitic crystallization based on degrees of silanization on MS surface results in the ZSM-5 samples have high external surface area and mesopore volume from intercrystalline among the nanoparticles. The evaluations of NH3-TPD, pyridine- and 2,6-ditertbutylpyridine-adsorbed FTIR as well as catalytic performances in benzylation reaction of 1,3,5-trimethylbenzene for the ZSM-5 zeolitic samples display the accessibility of acid sites and the catalytic activities for the synthesized hierarchical ZSM-5 zeolites are remarkably enhanced. It is clear that the results can be ascribed to the advantages of hierarchical ZSM-5 zeolites for the catalytic conversion of larger molecule, because of the reduction of the steric limitations and faster diffusion of the reaction species.
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      PubDate: 2016-11-12T09:01:21Z
      DOI: 10.1016/j.micromeso.2016.10.051
      Issue No: Vol. 240 (2016)
       
  • Ultrasonic spray pyrolysis as a processing route for templated
           electrochromic tungsten oxide films
    • Authors: D. Chatzikyriakou; A. Maho; R. Cloots; C. Henrist
      Pages: 31 - 38
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): D. Chatzikyriakou, A. Maho, R. Cloots, C. Henrist
      Mesoporous tungsten oxide films have been reported via numerous processing routes namely dip-coating, spin-coating, electrodeposition etc. and different porous architectures have been emerged. However, the templating strategy becomes more challenging when associated with the more industrially compelling spraying methods. The confined environement of the droplets, the temperature gradient during the droplets trajectory along with the relatively high substrate temperature might severely alter the delicate kinetics of the mesophase process. In this publication, we attest that templating can be effectively combined with the Ultrasonic Spray Pyrolysis method by a careful control of the deposition conditions. The emerging films are structurally characterized in the presence and absence of a surfactant over a temperature range (100 °C-390 °C) in order to determine the optimal deposition temperature. Smooth, uniform films are obtained at lower deposition temperatures (100 °C and 190 °C) and only in the presence of a surfactant. Therefore, surfactants are essentially acting as both wetting and templating agents at the same time. Finally, we emphasize on the role of porosity on enhancing the electrochromic properties of the films. Noticeably improved optical contrast (59 vs. 4%), coloration efficiency (40 vs. 6 cm2.C−1) and capacity (20 vs. 5 mC cm−2) is observed for the porous films compared to their dense counterparts.
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      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.11.001
      Issue No: Vol. 240 (2016)
       
  • Understanding the dynamics, self-diffusion, and microscopic structure of
           hydrogen inside the nanoporous Li-LSX zeolite
    • Authors: M.H. Kowsari; Shabnam Naderlou
      Pages: 39 - 49
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): M.H. Kowsari, Shabnam Naderlou
      The dynamical and structural properties of hydrogen (H2) guest gas inside nanoporous Li-LSX zeolite were studied by molecular dynamics (MD) simulation for different loadings (8, 12, 16, and 20) of H2 per unit cell at temperatures of 200, 298, 400, and 500 K. Three equal mean-square displacement (MSD) components (in the x, y, and z-directions) for the center of mass of H2 guest molecules show that the translational motion of H2 in this zeolite medium is isotropic due to the high symmetry of the zeolite framework. At these conditions, H2 guest molecules freely move without blocking each other's path into the supercages and channels of the Li-LSX zeolite. The order of calculated self-diffusion coefficient of H2 guest molecules at different temperatures, in the range of 10−9 up to 10−7 m2 s−1, and corresponding activation energy, ∼2 kcal mol−1, followed using the Arrhenius equation is in good agreement with the pores size of Li-LSX zeolite (7.4–12 Å) and compatible with inter-region of well-known Knudsen and Configurational diffusion. The H2 self-diffusion coefficients increase with temperature, while showing no quantifiable changes with loading within this loading range. A further study with a broader guest loading range would be appropriate to fully understand the loading effect on the self-diffusion of H2 guest molecules in the Li-LSX zeolite as the H2 storage candidate. In addition to determining the temperature and loading effects on the H2 guest behavior, current simulations also show that the Li-III cations are specific H2 sorption sites and the structural correlation, dynamics, self-diffusion coefficient, and adsorption of H2 molecules are strongly dependent on the mobility or immobility of the key extraframework Li-III cationic sites of Li-LSX zeolite. The results of the simulation help in the choice of favorable structure, best design, and operative manufacture of zeolites or other microporous materials for similar applications.
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      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.10.042
      Issue No: Vol. 240 (2016)
       
  • Synthesis of mesoporous K2O-In2O3 nanowires and NOx gas sensitive
           performance study in room temperature
    • Authors: Afrasiab Ur Rehman; Jiawei Zhang; Jiao Zhou; Kan Kan; Li Li; Keying Shi
      Pages: 50 - 56
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Afrasiab Ur Rehman, Jiawei Zhang, Jiao Zhou, Kan Kan, Li Li, Keying Shi
      In this work, highly crystalline mesoporous In2O3 nanowires (NWs) doped with K2O, ZnCl2 or CaCl2 were synthesized by template-calcined method using SBA-16 as template. The mesoporous K2O-In2O3NWs (INW-K2), which was synthesized by mixing 0.2 mol L−1 In(NO3)3 solution with 0.02 g KNO3 so that In(NO3)3 and KNO3 mass ratio was 30:1, has high density of chemisorbed oxygen. Its diameter is about 4–8 nm and pore size is 3–5 nm. For INW-K2, K2O doped on its surfaces serves as alkaline center and benefits the adsorption and diffusion of acidic NOx. Meanwhile, the INW-K2 provides large number of active centers for gaseous reactions on the surface of the nanowires. Therefore, the gas sensing property of INW-K2 is significantly improved, the response of NOx to 97 ppm is about 151.78 and response time is only 12 s, the detection limitation decreased to 48.5 ppb at room temperature (RT). The highly crystalline mesoporous K2O-In2O3 nanowires might offer a new opportunity for synthesizing multifunctional sensing materials in future.
      Graphical abstract image

      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.11.006
      Issue No: Vol. 240 (2016)
       
  • NASICON type ordered mesoporous lithium-aluminum-titanium-phosphate as
           electrode materials for lithium-ion batteries
    • Authors: Piyali Bhanja; Chenrayan Senthil; Astam Kumar Patra; Manickam Sasidharan; Asim Bhaumik
      Pages: 57 - 64
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Piyali Bhanja, Chenrayan Senthil, Astam Kumar Patra, Manickam Sasidharan, Asim Bhaumik
      An ordered 2D-hexagonal mesoporous Lithium-Aluminum-Titanium-Phosphate (LATP-1) material has been synthesized by using cetyltrimethylammonium bromide (CTAB) as the structure directing agent (SDA) thorough hydrothermal route. After acid-ethanol extraction of the as-synthesized LATP-1 material, the extracted white solid product has been characterized thoroughly using small and wide angle powder X-ray diffraction (XRD), nitrogen adsorption/desorption analysis, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), Ultra-high resolution transmission electron microscopy (UHR-TEM) and thermogravimetric analysis (TGA). Elemental analysis revealed 2.53% Li, 2.02% Al, 4.84% Ti, 28.16% P, 62.44% O in the mesoporous LATP-1 material. The template-extracted LATP-1 material has been employed as anode and cathode materials for lithium ion batteries: as an anode material, the LATP-1 electrode exhibits stable discharge-charge performances with delivered capacity of 121 mAh.g−1 and 117 mAh.g−1, respectively and a high coulombic efficiency.
      Graphical abstract image

      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.11.005
      Issue No: Vol. 240 (2016)
       
  • Incorporating poly(3-hexyl thiophene) into orthogonally aligned
           cylindrical nanopores of titania for optoelectronics
    • Authors: Suraj Nagpure; James F. Browning; Stephen E. Rankin
      Pages: 65 - 72
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Suraj Nagpure, James F. Browning, Stephen E. Rankin
      The incorporation of hole conducting polymer poly(3-hexyl thiophene) (P3HT) into the 8–9 nm cylindrical nanopores of titania is investigated using films with a unique orthogonally oriented hexagonal close packed mesostructure. The films are synthesized using evaporation induced self-assembly (EISA) with Pluronic triblock copolymer F127 as the structure directing agent. The orthogonally oriented cylindrical nanopore structure was chosen over a cubic structure because confinement in uniform cylindrical channels is hypothesized to enhance hole conductivity of P3HT by inducing local polymer chain ordering. Orthogonal orientation of the cylindrical nanopores is achieved by modifying the substrate (FTO-coated glass slides) with crosslinked F127. After thermal treatment to remove organic templates from the films, P3HT is infiltrated into the nanopores by spin coating a 1 wt% P3HT solution in chlorobenzene onto the titania films followed by thermal annealing under vacuum at 200 °C. The results show that infiltration is essentially complete after 30 min of annealing, with little or no further infiltration thereafter. A final infiltration depth of ∼14 nm is measured for P3HT into the nanopores of titania using neutron reflectometry measurements. Photoluminescence measurements demonstrate that charge transfer at the P3HT-TiO2 interface improves as the P3HT is infiltrated into the pores, suggesting that an active organic-inorganic heterojuction is formed in the materials.
      Graphical abstract image

      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.10.050
      Issue No: Vol. 240 (2016)
       
  • Porous carbons derived from pyrene-based conjugated microporous polymer
           for supercapacitors
    • Authors: Yang Zhao; Fangyuan Xie; Chong Zhang; Rui Kong; Shi Feng; Jia-Xing Jiang
      Pages: 73 - 79
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Yang Zhao, Fangyuan Xie, Chong Zhang, Rui Kong, Shi Feng, Jia-Xing Jiang
      Porous carbons with high surface area were obtained by pyrolysis of a pyrene-based conjugated microporous polymer with potassium hydroxide active agent. Nitrogen adsorption and desorption measurements demonstrated that the surface area, pore volume, pore size and pore size distributions of the resulting carbon materials are significantly dependent on the activation temperature. The performances of the supercapacitors fabricated from these carbon materials were investigated by cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy, electrochemical capacitance and long cyclic stability. The results revealed that SDBPy-800-based electrode shows the highest specific capacitance of 301 F g−1 at a current density of 1 A g−1 in a three-electrode system among the three carbonized materials. A symmetric supercapacitor was further fabricated from SDBPy-800 in a two-electrode system, which also exhibits a high specific capacitance of 176 F g−1 at a current density of 0.25 A g−1, high rate capability and excellent cycling stability with the capacitance retention of 92.6% after 10,000 cycles. These results demonstrated that these porous carbon materials are promising for high-performance supercapacitors.
      Graphical abstract image

      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.10.048
      Issue No: Vol. 240 (2016)
       
  • Magnetic mesoporous silica Fe3O4@SiO2@meso-SiO2 and
           Fe3O4@SiO2@meso-SiO2-NH2 as adsorbents for the determination of trace
           organic compounds
    • Authors: Dawid Lewandowski; Michał Cegłowski; Marek Smoluch; Edward Reszke; Jerzy Silberring; Grzegorz Schroeder
      Pages: 80 - 90
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Dawid Lewandowski, Michał Cegłowski, Marek Smoluch, Edward Reszke, Jerzy Silberring, Grzegorz Schroeder
      Magnetic nanoparticles, Fe3O4@SiO2@meso-SiO2 and Fe3O4@SiO2@meso-SiO2-NH2, have been prepared and used as adsorbents for the detection of trace organic compounds. Selected organic acids and bases were adsorbed from their solutions onto the surface of suspended magnetic solids. Adsorbents were then attracted by ferrite magnets immersed in the solutions and transferred to the mass spectrometer, where thermal desorption of the analytes occurred by the use of a programmed heating system. The plasma stream ionized the molecules and transported the resulting ions to the analyzer. The procedure presented in this paper covers preparation and characterization of magnetic, mesoporous silica carriers, as well as their application in fast and inexpensive method of detection, omitting time-consuming purification steps. Flowing atmospheric pressure afterglow (FAPA) mass spectrometry is presented, as an analytical method for the analysis of selected analytes in solution. Significant influence of surface functionalization and controllable thermal desorption process on the identification of analytes has been described.
      Graphical abstract image

      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.11.010
      Issue No: Vol. 240 (2016)
       
  • 3D Bi2MoO6 hollow mesoporous nanostructures with high photodegradation for
           tetracycline
    • Authors: Jinwu Bai; Yun Li; Jiandang Liu; Lu Liu
      Pages: 91 - 95
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Jinwu Bai, Yun Li, Jiandang Liu, Lu Liu
      The Bi2MoO6 hollow mesoporous nanostructured have been successfully synthesized by a template-free solvothermal process. The structural and morphological of Bi2MoO6 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The obtained Bi2MoO6 hollow mesoporous spheres exhibited greatly photocatalytic activity for photodegradation of tetracycline (TC) aqueous solution, which could be attributed to the synergistic effect of catalysts structure including large surface area, the energy band structures, porous hollow sphere structure and light absorbance. The Bi2MoO6 hollow mesoporous spheres photocatalytic superiority would be practicable for the application in the fields of photocatalytic degradation hazard pollutants.
      Graphical abstract image

      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.11.008
      Issue No: Vol. 240 (2016)
       
  • Improved catalytic performance and decreased coke formation in
           post-treated ZSM-5 zeolites for methanol aromatization
    • Authors: Feng Zhou; Yan Gao; Guang Wu; Fangwei Ma; Chuntao Liu
      Pages: 96 - 107
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Feng Zhou, Yan Gao, Guang Wu, Fangwei Ma, Chuntao Liu
      The effects of the zeolite structure and acidity on the catalyst life and coke formation in the methanol-to-aromatics (MTA) reaction were investigated using several MFI zeolites with different degrees of mesoporosity and acidity. These zeolites were prepared by post-synthesis desilication, dealumination, and combined desilication and dealumination processes. The influence of the post-synthesis on the pore characteristics, crystallinity, morphology and acidity of the ZSM-5 zeolites were studied by XRD, N2-adsorption, n-octane temperature-programmed desorption experiments, 27Al and 29Si MAS NMR, SEM, TEM and NH3-TPD. Dealumination and/or desilication leads to an increase in the mesoporosity by widening the micropores and a decrease in the acid density. The MTA catalyst lifetime is increased by several times due to the enhanced mesoporosity and decreased acid density. The deactivated catalysts were characterized by thermogravimetry and N2 adsorption/desorption experiments. More coke forms inside the micropores than on the external surfaces of the catalysts. Generalized and quantitative correlations between the mesoporosity and coke content and between the number of acid sites and coke content are given.
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      PubDate: 2016-11-20T03:21:59Z
      DOI: 10.1016/j.micromeso.2016.11.014
      Issue No: Vol. 240 (2016)
       
  • Preparation and characterization of porous Fe-Cu mixed oxides modified
           ZSM-5 coating/PSSF for continuous degradation of phenol wastewater
    • Authors: Songshan Jiang; Huiping Zhang; Ying Yan; Xinya Zhang
      Pages: 108 - 116
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Songshan Jiang, Huiping Zhang, Ying Yan, Xinya Zhang
      The porous Fe-Cu mixed oxides modified ZSM-5 coating/PSSF (paper-like sintered stainless steel fibers) catalysts were synthesized for the continuous degradation of phenol by means of catalytic wet peroxide oxidation. The catalysts were firstly characterized by XRD, N2 adsorption-desorption, SEM and EDS. Then, the activity of the catalysts was evaluated in a continuous reactor at the temperature of 80 °C under atmospheric pressure. The results indicated that phenol conversion of 100% and H2O2 conversion of 98% was obtained and the phenol can be oxidized into organic acids directly without toxic quinones by-products detected. The increase of Cu element can obviously increase the catalytic activity of FeCu-ZSM-5 coating/PSSF catalyst, and the doped of Cu element can effectively increase the stability of Fe active component. H2-TPR and XPS experiments were further carried out to investigate the interactions of the bimetallic component. Finally, catalytic reaction mechanisms of the phenol degradation over the catalysts were proposed. The excellent catalytic activity of the FeCu-ZSM-5 catalysts was resulted from synergistic effect of the Cu, Fe active component and high contacting efficiency of the ZSM-5 coating/PSSF support.
      Graphical abstract image

      PubDate: 2016-11-26T09:00:35Z
      DOI: 10.1016/j.micromeso.2016.11.020
      Issue No: Vol. 240 (2016)
       
  • Flexibility of the imidazolium based ionic liquids/water system for the
           synthesis of siliceous 10-ring containing microporous frameworks
    • Authors: Inés Lezcano-González; Matthew G. O'Brien; Marta Počkaj; Manuel Sánchez-Sánchez; Andrew M. Beale
      Pages: 117 - 122
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Inés Lezcano-González, Matthew G. O'Brien, Marta Počkaj, Manuel Sánchez-Sánchez, Andrew M. Beale
      By using asymmetric di-substituted imidazolium molecules (1-Butyl-3-methylimidazolium (BMIM) and 1-Ethyl-3-methylimidazolium (EMIM) bromide) as the structure directing agents, in combination with simple changes in silica source or sodium/water content it is possible to prepare three pure phase microporous 10-ring siliceous zeolitic structures. The crystallizations are comparatively rapid with fully crystalline material resulting in 1–3 days at 443 K. In contrast to many recipes reported for pure silica materials, the synthesis is performed without the use of HF or without the need to alter the properties of the SDA, while significantly lower amounts of both ionic liquid and mineralizing agent are required. The results obtained indicate that effective phase control can be achieved from a primary gel composition by minor changes to either the silica source or the water/sodium content, with a strong specificity in the formation of topologies with interconnected 10-rings.
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      PubDate: 2016-11-26T09:00:35Z
      DOI: 10.1016/j.micromeso.2016.11.019
      Issue No: Vol. 240 (2016)
       
  • Dry-gel synthesis of mesoporous MFI zeolite nanosponges using a
           structure-directing surfactant
    • Authors: Seung Won Han; Jaeheon Kim; Ryong Ryoo
      Pages: 123 - 129
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Seung Won Han, Jaeheon Kim, Ryong Ryoo
      The synthesis of mesoporous MFI zeolite nanosponges was investigated in a dry-gel conversion process using C18H37 N+(CH3)2 C6H12 N+(CH3)2 C4H9 as a micropore-mesopore hierarchical structure-directing surfactant. The initial synthesis mixture was converted at 333 K to a mesoporous material exhibiting a structure similar to that of MCM-41. The mesoporous material was filtered, dried at 373 K, and subsequently heated at 423 K in an autoclave with controlled humidity. In this process, precise control of the relative chamber humidity and the pH of the precursor gel was necessary to achieve full crystallization of the zeolite. The final product was composed of three-dimensional networks of 2.5-nm thick MFI nanolayers and exhibited a high surface area and narrow distribution of mesopore diameters centered at 4 nm. The zeolite crystallization behavior at 423 K was investigated after various heating times with X-ray diffraction, gas adsorption, and electron microscopy. The results indicated that under controlled humidity, crystallization took place through a pseudomorphic transformation, where the initial gel morphology was maintained throughout. The overall quality of the dry-gel product was similar to that of a conventional hydrothermal product. The Si/Al ratios of the zeolite could be controlled over the range of 50 ∼ ∞. Furthermore, in a 100-g synthesis batch, the dry-gel method had the advantage of compact autoclave size for large-scale synthesis.
      Graphical abstract image

      PubDate: 2016-11-26T09:00:35Z
      DOI: 10.1016/j.micromeso.2016.11.016
      Issue No: Vol. 240 (2016)
       
  • Deep eutectic solvent immobilized on SBA-15 as a novel separable catalyst
           for one-pot three-component Mannich reaction
    • Authors: Najmedin Azizi; Mahtab Edrisi
      Pages: 130 - 136
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Najmedin Azizi, Mahtab Edrisi
      An environmentally friendly and recyclable nanocomposite (HNMPCl/ZnCl2/SBA-15) was prepared by impregnation of N-methylpyrrolidonium-zinc chloride based deep eutectic solvent (HNMPCl/ZnCl2) on SBA-15. The catalytic activity of HNMPCl/ZnCl2/SBA-15 was investigated towards the one-pot three-component Mannich type reaction to a series of aldehydes, ketones, and amines and provided excellent activity and selectivity for the synthesis of β-amino ketones under mild reaction condition in green solvent. The HNMPCl/ZnCl2/SBA-15 was prepared using simple method from readily available starting material and was confirmed by FTIR, SEM, XRD, BET, and EDX. This protocol features green and efficient catalyst, ease of work up, simple separation without chromatography and reusability of the HNMPCl/ZnCl2/SBA-15 for four runs are the important highlights of this process, that it will find a wide variety of applications in academic and industrial research.
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      PubDate: 2016-11-26T09:00:35Z
      DOI: 10.1016/j.micromeso.2016.11.009
      Issue No: Vol. 240 (2016)
       
  • Effect of nitridation on visible light photocatalytic behavior of
           microporous (Ag, Ag2O) co-loaded TiO2
    • Authors: Mingming Zou; Honghong Liu; Lu Feng; Fengqiang Xiong; Tiju Thomas; Minghui Yang
      Pages: 137 - 144
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Mingming Zou, Honghong Liu, Lu Feng, Fengqiang Xiong, Tiju Thomas, Minghui Yang
      A simple solvothermal approach with post-calcination is used to obtain (Ag, Ag2O) co-loaded TiO2 microspheres with high specific surface area (43.8 m2g-1) and desirable visible light photocatalytic degradation (64% after 2 h visible light irradiation). Generally, N-doping of TiO2 via nitridation using NH3 improves the visible light absorption property of material. However, nitridation of (Ag, Ag2O) co-loaded TiO2 results in a deleterious impact on the photocatalytic performance (around 20% after 2 h visible light irradiation). This is because nitridation of Ag-Ag2O-TiO2 results in (a) reduction of Ag2O to Ag and (b) Ag agglomeration and grain growth on TiO2 particles. These results in fact imply that in as-synthesized (Ag, Ag2O) co-loaded TiO2 systems, local surface plasmonic resonance (associated with of 5–12 nm Ag particles) aids in enhanced broad band visible light absorption; furthermore the heterojunction between TiO2 and Ag2O improves efficiency with which photogenerated carriers become available for photocatalysis. In all cases we show through selective radical quenching experiments that singlet oxygen is the primary reason for the dye degradation observed.
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      PubDate: 2016-11-26T09:00:35Z
      DOI: 10.1016/j.micromeso.2016.11.018
      Issue No: Vol. 240 (2016)
       
  • Regulating pore structure of carbon aerogels by graphene oxide as
           ‘shape-directing’ agent
    • Authors: Feng Li; Lijing Xie; Guohua Sun; Qingqiang Kong; Fangyuan Su; Hong Lei; Xiangyun Guo; Bingsen Zhang; Chengmeng Chen
      Pages: 145 - 148
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Feng Li, Lijing Xie, Guohua Sun, Qingqiang Kong, Fangyuan Su, Hong Lei, Xiangyun Guo, Bingsen Zhang, Chengmeng Chen
      With graphene oxide (GO) as ‘shape-directing’ agent, carbon aerogels with tunable hierarchical porous structure were prepared by one-step carbonization method. It was found that the content of GO had a significant effect on their pore structures. When GO loading was up to 1.43 wt‱, it possessed an ultrahigh specific surface area (SSA) of 2728 m2 g−1, large pore volume of 1.82 cm3 g−1 and excellent mechanical properties. Benefiting from the high SSA and unique hierarchical porous microstructure, possible future applications of the as-obtained carbon aerogels could be in the fields of energy storage, electrochemistry, and adsorption.
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      PubDate: 2016-11-26T09:00:35Z
      DOI: 10.1016/j.micromeso.2016.10.052
      Issue No: Vol. 240 (2016)
       
  • Emulsion-mediated synthesis of hierarchical mesoporous-macroporous Al-Mg
           hydrotalcites
    • Authors: Davi D. Petrolini; Ernesto A. Urquieta-González; Sandra H. Pulcinelli; Celso V. Santilli; Leandro Martins
      Pages: 149 - 158
      Abstract: Publication date: 1 March 2017
      Source:Microporous and Mesoporous Materials, Volume 240
      Author(s): Davi D. Petrolini, Ernesto A. Urquieta-González, Sandra H. Pulcinelli, Celso V. Santilli, Leandro Martins
      A new sol-gel method mediated by the use of paraffin emulsions is presented for the synthesis of hierarchical mesoporous-macroporous Al-Mg hydrotalcites. Prior to the synthesis, the construction of ternary diagrams for paraffin/surfactant/ethanol helped to identify the most suitable compositional synthesis domain. Two distinct regions, denoted L1 (transparent microemulsion) and L2 (opaque emulsion) were identified for low and high concentrations of paraffins, respectively. The ternary diagrams revealed some features: i) n-hexane (C6) had the smallest L2 region; ii) the high viscosity of n-octadecane (C18) did not allow control of phase separation, and iii) the most suitable paraffin for the use as the emulsifier was the intermediate-sized n-dodecane (C12). The use of paraffin in concentrations included in the L1 region did not contribute to the creation of pores, but the emulsion templating in the L2 region led to hierarchical porous hydrotalcites when were calcined up to 250 °C having enhanced textural properties and presenting mesopores and macropores with mean sizes of 0.02 and 1 μm, respectively. The slit-like shaped mesopores were caused by the partial exfoliation of hydrotalcite layers unordered packed around the emulsion droplets, while the macropores arose from voids left by the droplets after thermal treatment. The singular textural properties of the studied Al-Mg hierarchical porous hydrotalcites turns the emulsion mediated-synthesis a potential method to obtain more efficient catalysts to be used in process involving bulky molecules.
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      PubDate: 2016-11-26T09:00:35Z
      DOI: 10.1016/j.micromeso.2016.11.011
      Issue No: Vol. 240 (2016)
       
  • Interface-assisted synthesis of mesoporous silica nanoparticles using neat
           tetraalkoxysilanes
    • Authors: Norihiro Mizoshita; Hiromitsu Tanaka
      Pages: 1 - 8
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Norihiro Mizoshita, Hiromitsu Tanaka
      Here we propose an efficient and interface-assisted synthetic method of mesoporous silica nanoparticles (MSNs). MSNs have great potential for various functional applications, such as carriers for drug delivery, solid support of catalysts, and low-refractive-index components of antireflection coatings. However, there have still been difficulties in realizing easy synthesis of MSNs with accurate particle size and high porosity. In the present study, MSNs are synthesized by spreading neat tetraalkoxysilanes on aqueous solutions containing a template surfactant and a catalyst. Our strategy is to hydrolyze the silica sources at the tetraalkoxysilane–water interface and supply the hydrolyzed precursors into the aqueous phase gradually and constantly. In this case, nucleation of MSNs occurs in the initial stage of the reaction, and then steady growth of MSNs is promoted by the constant supply of the silica sources through the tetraalkoxysilane–water interface. MSNs with a spherical shape and high porosities are obtained when neat tetrapropoxysilane is used at 50 °C. The relationship between particle size of the resulting MSNs and reaction time is described by a simple numerical formula, which enables us to control or predict the particle sizes of MSNs with a narrow size distribution.
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      PubDate: 2016-10-02T11:18:53Z
      DOI: 10.1016/j.micromeso.2016.09.025
      Issue No: Vol. 239 (2016)
       
  • Performance of mesoporous silicas and carbon in adsorptive removal of
           phenanthrene as a typical gaseous polycyclic aromatic hydrocarbon
    • Authors: Ziyi Li; Yingshu Liu; Xiong Yang; Yi Xing; Chuen-Jinn Tsai; Miaomiao Meng; Ralph T. Yang
      Pages: 9 - 18
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Ziyi Li, Yingshu Liu, Xiong Yang, Yi Xing, Chuen-Jinn Tsai, Miaomiao Meng, Ralph T. Yang
      Adsorptive removal of the predominant polycyclic aromatic hydrocarbons (PAHs), represented by phenanthrene, from hot gases using mesoporous adsorbents (mesosilicas MCM-41 and SBA-15, and mesocarbon CMK-3) has been studied through tests of column adsorption and temperature programmed desorption (TPD). Adsorption equilibria on MCM-41 and CMK-3, and on SBA-15 were well described by Langmuir and Freundlich models, respectively, showing the order of adsorption capacity of CMK-3 > SBA-15 > MCM-41 originated from different geometrical structures and texture properties. Adsorption dynamics based on breakthrough fitting by the constant-pattern wave propagation model showed that mesoporosity contributed to fast overall adsorption kinetics by reducing the internal resistance as being the predominant mass-transfer step, particularly on SBA-15 with a 2-D cross-linked structure. The TPD tests revealed the order of ease of desorption of SBA-15 ≈ MCM-41 > CMK-3, where the structural advantage on SBA-15 dominated the strong site binding as indicated by the intrinsic activation energy and exponential factor obtained by TPD models. Results from different TPD models showed that re-adsorption effect during desorption increased with decreasing dimension of adsorbent structure and that the utilization of the simplified linear TPD model could be violated by the strong sorbate-sorbent binding. Comparisons with traditional adsorbents and with the removal of naphthalene by these mesoporous adsorbents were made, showing higher applicability of CMK-3 for phenanthrene regarding stronger adsorption affinity and capacity as well as decreased disadvantages in regenerability relative to mesosilicas.
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      PubDate: 2016-10-02T11:18:53Z
      DOI: 10.1016/j.micromeso.2016.09.027
      Issue No: Vol. 239 (2016)
       
  • Synthesis of mesoporous zeolites in fluoride media with
           structure-directing multiammonium surfactants
    • Authors: Changbum Jo; Woojin Park; Ryong Ryoo
      Pages: 19 - 27
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Changbum Jo, Woojin Park, Ryong Ryoo
      Mesoporous zeolite beta in pure-silica form and its analogues, including aluminosilicate, stannosilicate, and titanosilicate, were synthesized at near-neutral pH in the presence of fluoride ion as a mineralizer and piperidinium-functionalized multiammonium surfactant as a zeolite structure-directing agent (SDA). During hydrothermal synthesis, the surfactant headgroup generated zeolite beta frameworks with a thickness of 9 nm while numerous surfactant molecules were self-organized to form a nanosponge-like mesostructure in a disordered manner. The mesopores generated after calcination to remove the surfactant were highly uniform and further tailored with diameters in the range of 3.2–4.5 nm according to the surfactant tail lengths. MFI zeolite was also synthesized with a nanosheet morphology using C16H33 N+(CH3)2 C6H12 N+(CH3)2 C6H13 as the SDA in fluoride media. The zeolite samples obtained in this manner exhibited remarkably enhanced thermal stability, Brønsted acid strength, and hydrophobic nature compared to those synthesized at a high pH using OH− as the mineralizer due to the reduced defect sites, as confirmed by 29Si MAS NMR and FT-IR measurements. Due to these advantages, the mesoporous zeolite beta obtained in the fluoride media exhibited high catalytic activity in esterification of oleic acid with methanol.
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      PubDate: 2016-10-02T11:18:53Z
      DOI: 10.1016/j.micromeso.2016.09.037
      Issue No: Vol. 239 (2016)
       
  • Rapid room temperature synthesis forming pillared metal-organic frameworks
           with Kagomé net topology
    • Authors: Kui Zhou; Somboon Chaemchuen; Zhaoxuan Wu; Francis Verpoort
      Pages: 28 - 33
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Kui Zhou, Somboon Chaemchuen, Zhaoxuan Wu, Francis Verpoort
      A direct synthesis of pillared metal-organic frameworks with Kagomé net topology under mild conditions (room temperature and ambient pressure) was developed which provides a straightforward and energy-saving procedure to produce MOFs. A series of metals (M = Zn, Ni and Co) bridging with ligands 1,4-benzene dicarboxylate (bdc) and 1,4-diazabicyclo[2.2.2]octane (dabco) were used to construct MOF frameworks denoted as M2(bdc)2(dabco). The Kagomé net pillared structures were confirmed via crystal phase analysis (XRD). The use of different metals resulted in diverse crystal morphologies and particle shapes as observed from scanning electron microscope analysis (SEM). The obtained Kagomé net pillared structure influences the physical properties such as surface area, pore size, N2/CO2/CH4 gas adsorption and also thermal stability. Furthermore, modeling was applied to determine the behavior of the isosteric heat of adsorption on CO2 and gas selectivity of CO2/CH4 and CO2/N2.
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      PubDate: 2016-10-02T11:18:53Z
      DOI: 10.1016/j.micromeso.2016.09.038
      Issue No: Vol. 239 (2016)
       
  • Synthesis of all-silica DDR zeolite in an environment-friendly way
    • Authors: Lu Bai; Chen Liu; Meng Li; Yihui Wang; Guizhen Nan; Deng Hu; Yanfeng Zhang; Gaofeng Zeng; Wei Wei; Yuhan Sun
      Pages: 34 - 39
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Lu Bai, Chen Liu, Meng Li, Yihui Wang, Guizhen Nan, Deng Hu, Yanfeng Zhang, Gaofeng Zeng, Wei Wei, Yuhan Sun
      The synthesis of all-silica DDR zeolite is challenging and not green. The lengthy synthesis time, use of expensive template, solvents (water and ethylenediamine) and fluoride lead to high material cost, capital investment on autoclave and waste disposal issues. Here we propose an environment-friendly synthesis of all-silica DDR zeolite with significantly reduced consumption of organic template and solvent. The use of toxic solvent (ethylene diamine) and mineralizing agent (fluorides) was avoided. The obtained DDR samples were characterized by XRD, SEM, NMR, FT-IR, TGA, and nitrogen adsorption. High quality DDR crystals with high yield can be obtained in 2d with molar recipe of 1.0 SiO2: 1.0 H2O: 0.05 ADA, which is almost an atomic economic synthesis. Compared with regular hydrothermal synthesis, the Shelton E-factor was significantly reduced.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.043
      Issue No: Vol. 239 (2016)
       
  • Adsorption of phenol onto four hyper-cross-linked polymeric adsorbents:
           Effect of hydrogen bonding receptor in micropores on adsorption capacity
    • Authors: Guqing Xiao; Ruimin Wen; Peiqing You; Dan Wu
      Pages: 40 - 44
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Guqing Xiao, Ruimin Wen, Peiqing You, Dan Wu
      Different functional group modified hyper-cross-linked polymeric adsorbents H103, GQ-1, GQ-2 and GQ-5 were synthesized from macroporous crosslinked chloromethylated styrene-divinylbenzene copolymers. Phenol was selected as a hydrogen bonding donator. The object of this work was to explore the effect of hydrogen bonding receptor in micropores of adsorbent on adsorption capacity. Results showed the BET surface area and pore volume followed the order H103 > GQ-5 > GQ-2 > GQ-1 while the adsorption capacity of phenol onto the four hyper-cross-linked polymeric adsorbents followed the order GQ-1 > GQ-2 > GQ-5 > H103. The density functional theory indicated that hydrogen bonding receptor in micropores of the adsorbents was a crucial factor for the adsorption capacity order.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.044
      Issue No: Vol. 239 (2016)
       
  • Activated carbon monoliths from particle stabilized foams
    • Authors: D. Zabiegaj; M.T. Buscaglia; D. Giuranno; L. Liggieri; F. Ravera
      Pages: 45 - 53
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): D. Zabiegaj, M.T. Buscaglia, D. Giuranno, L. Liggieri, F. Ravera
      Particle stabilized liquid foams are used as templates to obtain carbon-based porous materials with open cell structure, high specific area and hierarchical porosity. This route relies on gel casting to strengthen the structure of the liquid foams, followed by high temperature treatment to eliminate organic components and obtain solid foams. The liquid foam stabilizer was a commercial activated carbon powder, characterized by high porosity and irregular morphology of the particles, associated with a cationic surfactant. The micro-structure and the textural properties of the final solid materials have been investigated by Scanning Electronic Microscopy and Nitrogen adsorption methods. The results show that this method can be used to fabricate high specific area porous materials in the form of monoliths, with adequate consistence and mechanical resistance. The materials obtained seem promising for many practical applications such as gas adsorption, filtering and catalysis.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.046
      Issue No: Vol. 239 (2016)
       
  • Template removal by ion-exchange extraction from siliceous MCM-41
           synthesized by microwave-assisted hydrothermal method
    • Authors: Krittanun Deekamwong; Jatuporn Wittayakun
      Pages: 54 - 59
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Krittanun Deekamwong, Jatuporn Wittayakun
      Cetyltrimethylammonium (CTA+) bromide is a template in the synthesis of MCM-41 which is normally removed by calcination. This work focuses on removal of CTA+ by ion-exchange extraction from a siliceous MCM-41 synthesized by microwave-assisted hydrothermal method. The extraction was first conducted with aqueous and methanolic solution of NH4Cl under sonication. Methanol was a better solvent and further used with salts of various cation and anion. The extraction in the presence of ammonium salts was better than sodium and potassium salts due to the less change of the MCM-41 structure. In contrast, the type of anion in the ammonium salts had no effect on the removal efficiency. The methanolic solution containing NH4Cl was further studied from 15 min to 120 min and from 30 °C to 60 °C. The longer time and higher temperature improved the template removal but the extraction for 15 min at 60 °C was sufficient in terms of energy consumption.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.049
      Issue No: Vol. 239 (2016)
       
  • The application of green tea extract to prepare bentonite-supported
           nanoscale zero-valent iron and its performance on removal of Cr(VI):
           Effect of relative parameters and soil experiments
    • Authors: Akbar Soliemanzadeh; Majid Fekri
      Pages: 60 - 69
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Akbar Soliemanzadeh, Majid Fekri
      Bentonite-supported “green” nanoscale zero-valent iron (B-nZVI) were prepared using green tea extracts characterized and employed for Cr(VI) adsorption. FE-SEM-EDS, TEM confirmed that nZVI (40–80 nm) has been successfully loaded and efficiently dispersed on bentonite. According FTIR and EDS analysis the synthesized B-nZVI were composed of polyphenols and other C-containing molecules from green tea extracts acting as both reducing and capping agents. Batch experiments were conducted to measure the effects on adsorption of Cr(VI) of different parameters such as initial concentrations, ionic strength, adsorbent dosage, pH of the medium and contact times. The results showed that synthesized B-nZVI has much higher adsorption capacity for Cr(VI) compared to bentonite. The adsorption was highly dependent on pH providing maximum adsorption at pH range of 2–6. The adsorption isotherm and kinetic data for B-nZVI was fitted well with the Langmuir and pseudo-second order model, respectively, which implied that the adsorption process was chemisorptions. The results of soil experiment showed that the addition of adsorbents including bentonite and B-nZVI decreased the release of Cr as compared with Cr-control treatment. However, application of B-nZVI (2 and 4%) significantly reduced the exchange fraction (EX) and subsequently increased the FeMn oxide-bound (ox), and residual (RS) fractions. These results indicated the adsorption property of B-nZVI gives the compound with great potential for applications in environmental remediation.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.050
      Issue No: Vol. 239 (2016)
       
  • Preparation and characterization of a novel double-walled Na2(TiO)SiO4
           nanotube by hydrothermal process with CTAB as an assistant
    • Authors: Yuke Zhong; Sha Chang; Guojun Dong
      Pages: 70 - 77
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Yuke Zhong, Sha Chang, Guojun Dong
      A double-walled Na2(TiO)SiO4 nanotube was prepared by an effective hydrothermal process with cetyltrimethyl ammonium bromide (CTAB) as an assistant. The precursor SiO2-TiO2 composite powder with diverse Si/Ti molar ratios was prepared by co-precipitation method using silica sol and titanyl sulfate as raw materials. Then it was added into the NaOH aqueous solution with CTAB for hydrothermal reaction. The Na2(TiO)SiO4 nanotubes were characterized by X-ray diffraction (XRD), thermogravimetric and differential scanning calorimeter (TG-DSC), transmission electron microscope (TEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (29Si-NMR), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and N2 adsorption-desorption. The results showed that the Na2(TiO)SiO4 nanotubes are of large specific surface area, double-wall and Q0 structure. The length of Na2(TiO)SiO4 nanotubes can be controlled by adjusting the Si/Ti molar ratios from 100 nm to several hundred nanometers. A possible formation mechanism of the novel double-walled Na2(TiO)SiO4 nanotubes was also proposed.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.041
      Issue No: Vol. 239 (2016)
       
  • Near-infrared light activated photodynamic therapy of THP-1 macrophages
           based on core-shell structured upconversion nanoparticles
    • Authors: Hao Wang; Xing Zhu; Renlu Han; Xin Wang; Liming Yang; You Wang
      Pages: 78 - 85
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Hao Wang, Xing Zhu, Renlu Han, Xin Wang, Liming Yang, You Wang
      Upconversion nanoparticles (UCNPs) with fascinating properties hold great potential as nanotransducers for solving the light penetration problem that traditional photodynamic therapy (PDT) is facing. In this report, the synthesis and utility of UCNPs/silica core-shell structured nanoparticles for upconversion (UC) PDT and imaging of THP-1 macrophages were described. The UCNPs (NaYF4:Yb, Er) with a uniform diameter of 28 ± 1 nm were synthesized as core and 10 nm thick biocompatible mesoporous silica was coated as shell. Photosensitizer (PS) was covalently grafted inside mesoporous silica shell. Upon excitation, NIR light is converted into visible one by UCNPs for the absorption of PS to generate singlet oxygen for killing THP-1 macrophages and inhibiting the development of atherosclerosis. The fluorescence images showed the resulting nanoparticles are readily taken up by macrophages and TEM results indicated that they are highly phototoxic. The statistical in vitro results revealed PDT could cause the apoptosis of THP-1 macrophages with a remarkable therapeutic efficacy of cell inhibition ratio of 40%.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.048
      Issue No: Vol. 239 (2016)
       
  • Cooperative sorption of weak and strong electrolytes in microporous
           adsorbents
    • Authors: Markku Laatikainen; Tuomo Sainio
      Pages: 86 - 95
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Markku Laatikainen, Tuomo Sainio
      Sorption of pure electrolytes and binary electrolyte mixtures in non-ionic microporous adsorbents was studied in batch and fixed-bed systems. Hypercrosslinked polystyrene (HCPS) and densely crosslinked dextran gel (G10) were used as adsorbents and the studied model systems were HCl/CaCl2/HCPS at 25 °C and Na2-tartrate/NaOH/G10 at 50 °C. The results were explained in terms of cooperative sorption and the experimental data were correlated using a generalized Donnan equilibrium model together with Pitzer model for evaluation of the ion-ion and ion-adsorbent interactions. Moreover, a model was included for partial ion dehydration at high concentrations. Non-linear sorption observed at very low and high concentrations of pure electrolytes was explained by electrostatic exclusion and partial ion dehydration. In binary mixtures, a more complex behavior was observed because of cooperativity and good separation of the electrolyte mixtures was obtained in the fixed-bed experiments involving pulse feed and elution with pure water. In the HCl/CaCl2/HCPS system, selective uptake of HCl was enhanced by increasing the total electrolyte concentration. This trend can be explained by taking into account both size exclusion of CaCl2 and the non-ideal behavior of the electrolyte mixture. Separation of Na2-tartrate and NaOH was dominated by size exclusion of the tartrate anion and well-defined separation is possible even at very high column loading. Moreover, the observed splitting of Na2-tartrate to NaH-tartrate and NaOH can be explained on the basis of cooperativity. The results suggest that the proposed model applies equally well to materials having rigid microporous structure and to densely cross-linked gels.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.054
      Issue No: Vol. 239 (2016)
       
  • An intense broadband sensitized near-infrared luminescence from Yb3+ and
           Bi3+ co-doped zeolite L crystals
    • Authors: Peng Li; Yang Xu; Zhiqiao Qin; Yige Wang; Huanrong Li
      Pages: 96 - 100
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Peng Li, Yang Xu, Zhiqiao Qin, Yige Wang, Huanrong Li
      Near infrared luminescence of trivalent lanthanide ions around 900–1600 nm has attracted increasing attention because of its potential applications in optical fiber, telecommunications technologies, solid state lasers and solar cells. Particularly, Yb3+ presents an essential role on solar cells due to its broad emission at 1000 nm matching well with the strongest spectral response of c-Si solar cell. Herein we report Yb3+-Bi3+ co-doped zeolilte L (ZL) hybrid materials through a simple ion exchange process and subsequent annealing at a comparatively low temperature (800 °C) under atmospheric conditions. Such a luminescence material displays a strong, long-lived, and intense broadband tunable NIR photoluminescence (PL) through the energy transfer from Bi3+ to Yb3+, which can be utilized as a potential efficiency-enhancing material for c-Si solar cells.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.052
      Issue No: Vol. 239 (2016)
       
  • An efficient catalyst of manganese supported on diatomite for toluene
           oxidation: Manganese species, catalytic performance, and
           structure-activity relationship
    • Authors: Peng Liu; Hongping He; Gaoling Wei; Dong Liu; Xiaoliang Liang; Tianhu Chen; Jianxi Zhu; Runliang Zhu
      Pages: 101 - 110
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Peng Liu, Hongping He, Gaoling Wei, Dong Liu, Xiaoliang Liang, Tianhu Chen, Jianxi Zhu, Runliang Zhu
      The work reports the preparation of diatomite-supported manganese catalysts by deposition-precipitation method, and their application for toluene oxidation. Microstructure and morphology of catalysts were investigated by Powder X-ray diffraction pattern (PXRD), thermogravimetric (TG), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen (N2) adsorption-desorption isotherms. Temperature-programmed reduction (TPR) and temperature-programmed surface reaction (TPSR) were used to analyze the reducibility of Mn species and the reactivity of surface oxygen species, respectively. The characterization results reveal that the manganese species were mainly in the phase of amorphous MnO2 and Mn2O3 on the diatomite, and the manganese species were successfully loaded on diatomite surface and filled in pores. With the increase of Mn content, the catalytic activity enhanced, due to the increase of surface oxygen species as adsorption-reaction sites. The Mn4+ played an important role in the superior catalytic activity towards toluene. The catalyst also displays high stability and superior activity towards toluene oxidation, which presents an applied interest. The effect of Mn content on the catalytic activity of catalysts was discussed in view of reaction mechanism and variations of physicochemistry properties.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.053
      Issue No: Vol. 239 (2016)
       
  • Evaluation of volatile iodine trapping in presence of contaminants: A
           periodic DFT study on cation exchanged-faujasite
    • Authors: Mouheb Chebbi; Siwar Chibani; Jean-François Paul; Laurent Cantrel; Michael Badawi
      Pages: 111 - 122
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Mouheb Chebbi, Siwar Chibani, Jean-François Paul, Laurent Cantrel, Michael Badawi
      Using periodic dispersion-corrected DFT calculations, the effect of potential inhibiting species (H2O, NO, CO, CH3Cl and Cl2) on the adsorption of iodine species (I2, CH3I) has been investigated over different monovalent (H, Li, Na, K, Rb, Cs, Cu and Ag) cation-exchanged faujasite. We have found out that van der Waals interactions play an important role and can contribute up to about 50% of the total adsorption energy for the alkaline series. Both computed adsorption energies at 0 K and adsorption enthalpies for temperatures ranging from 298 to 523 K highlight the following points: (i) CO and H2O have been identified as the most important inhibiting species; (ii) Hard cations such as H+ or Li+ are very sensitive to water whereas soft cations such as Cu+ and Ag+ can strongly adsorb I2 and CH3I. Therefore, Ag-FAU appears to be the most promising adsorbent in presence of all contaminants, except CO which can inhibit the adsorption of I2. These findings can help to improve the filtering devices used in nuclear plants to avoid the release of radioactive iodine in case of severe accident.
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      PubDate: 2016-10-09T21:40:59Z
      DOI: 10.1016/j.micromeso.2016.09.047
      Issue No: Vol. 239 (2016)
       
  • Synthesis and characterization of co-crystalline zeolite composite of
           LSX/A
    • Authors: Supak Tontisirin
      Pages: 123 - 129
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Supak Tontisirin
      The synthesis of co-crystalline zeolite composite of LSX and A as (Na/K)-LSX/A (nSi/nAl = 1.05) could be achieved by simply adjusting the molar ratio of KOH/SiO2 = 1 in the typical synthesis gel of zeolite LSX. The gel composition is 1SiO2: 0.45Al2O3: 2.5Na2O: 1KOH = 0.5K2O: 55.5H2O. The framework contains Na and K as cations in the structure. Its crystals show aggregate clumps (ca. 1–1.5 μm) of small crystallites with different shapes (ca. 200 nm). The composite shows unique properties comparing to its references of (Na/K)-LSX and (Na/K)-A as (1) its crystals possess hierarchical structure of bimodal micro- and mesopore with high pore volume of 0.27 cm3/g and (2) its structural transformation temperature is higher at ca. 963 °C. The experimental result shows that the practical working temperature is up to 600 °C. This (Na/K)-LSX/A composite is an effective adsorbent for heavy metal of copper(II) ions adsorption with high uptake capacity of 2.36 mmol/g or 150 mg/g at adsorption for 1 h. This value is comparable to that of (Na/K)-LSX.
      Graphical abstract image

      PubDate: 2016-10-16T22:57:12Z
      DOI: 10.1016/j.micromeso.2016.09.051
      Issue No: Vol. 239 (2016)
       
  • Polystyrene foam derived nitrogen-enriched porous carbon/graphene
           composites with high volumetric capacitances for aqueous supercapacitors
    • Authors: Qinxing Xie; Guohang Chen; Rongrong Bao; Yufeng Zhang; Shihua Wu
      Pages: 130 - 137
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Qinxing Xie, Guohang Chen, Rongrong Bao, Yufeng Zhang, Shihua Wu
      Polystyrene (PS) foam derived nitrogen-enriched porous carbon/graphene (AC/Gr) composites were prepared using ammonia, ethylene diamine and melamine as nitrogen sources, respectively. The as-prepared AC/Gr composites and graphene-free PS-derived porous carbon (PSAC) exhibit moderate specific surface areas in a range of 915–1489 m2 g−1. Compared to PSAC, AC/Gr composites exhibit significantly improved energy storage capability, a high gravimetric capacitance of 339 F g−1 or volumetric capacitance of 365 F cm−3 was achieved at a current density of 0.05 A g−1 in 6 M KOH aqueous electrolyte. The assembled aqueous symmetric supercapacitors are capable of deliver both high energy density and high power density, for example, 11.8 W h kg−1 (12.7 W h L−1) with a power density of 12.5 W kg−1 (13.4 W L−1), and 6.2 W h kg−1 (6.7 W h L−1) with 4.6 kW kg−1 (5.0 kW L−1) for MAC/Gr-based supercapacitor.
      Graphical abstract image

      PubDate: 2016-10-16T22:57:12Z
      DOI: 10.1016/j.micromeso.2016.10.007
      Issue No: Vol. 239 (2016)
       
  • Chromium (VI) removal from water by means of adsorption-reduction at the
           surface of amino-functionalized MCM-41 sorbents
    • Authors: Nicolás Fellenz; Francisco J. Perez-Alonso; Pedro P. Martin; José L. García-Fierro; José F. Bengoa; Sergio G. Marchetti; Sergio Rojas
      Pages: 138 - 146
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Nicolás Fellenz, Francisco J. Perez-Alonso, Pedro P. Martin, José L. García-Fierro, José F. Bengoa, Sergio G. Marchetti, Sergio Rojas
      A first study that demonstrates the capability of the amino-functionalized MCM-41 sorbents to reduce Cr(VI) to the less toxic trivalent state is presented. To achieve this aim two mesoporous ordered silica with MCM-41 pores arrangement were synthesized and surface modified by a post-synthetic treatment using 3-aminopropyltriethoxysilane in toluene. The modified silicas were characterized by powder X-ray diffraction (XRD), infrared spectroscopy(FT-IR), scanning electron microscopy (SEM), nitrogen adsorption–desorption experiments, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and thermogravimetric analysis (TGA). Hexavalent chromium adsorption experiments in aqueous media were carried out with the hybrid samples at pH 2 and room temperature until reach equilibrium conditions. The experimental results showed that the aminopropyl-functionalized MCM-41 sorbents adsorb Cr(VI) and partially reduce it to the less toxic Cr(III) state. It is proposed that Cr(VI) adsorption is produced by electrostatic interaction between HCrO4 − anions and positive ammonium groups of the sorbent surface and continues with the reduction to Cr(III) while a proton is released from the solid surface to the solution. Afterwards, Cr(III) is partially retained onto the samples surface due to the Lewis basicity of the nitrogen atoms.
      Graphical abstract image

      PubDate: 2016-10-16T22:57:12Z
      DOI: 10.1016/j.micromeso.2016.10.012
      Issue No: Vol. 239 (2016)
       
  • Co/MCM41 catalyst in the COProx reaction prepared by supercritical CO2
           reactive deposition
    • Authors: Soledad G. Aspromonte; Martín D. Mizrahi; Esther Alonso; José M. Ramallo-López; Alicia V. Boix
      Pages: 147 - 157
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Soledad G. Aspromonte, Martín D. Mizrahi, Esther Alonso, José M. Ramallo-López, Alicia V. Boix
      Co/MCM41 catalyst with 4.3 wt % Co (Co/sc) has been prepared by supercritical CO2 reactive deposition (‘scfrd’) and characterized by different physicochemical techniques. This synthesized method was compared with others conventional methodologies such as template-ion exchanged (Co/tie) and incipient wet impregnation (Co/iwi) with similar cobalt content. All the samples were studied as catalysts on the CO total oxidation (COTox) and preferential oxidation of CO on H2-rich streams (COProx). Incorporating cobalt with supercritical CO2 leads to a catalyst which produces values of CO conversion similar to those obtained by conventional methods such as incipient wetness impregnation (Co/iwi) or template-ion exchanged (Co/tie). It has been possible to identify different cobalt species present in catalysts depending on their synthesis methods by Temperature-Programmed Reduction (TPR), X-ray Photoelectronic (XPS), Laser Raman (LRS) and X-ray Absorption (XANES/EXAFS) spectroscopic studies. All samples containing a main cobalt species of cobalt (II) coordinated with Si tetrahedral sites form part of mesoporous structure and lesser extent, cobalt orthosilicate on the surface. In addition, Co3O4 species dispersed over the MCM41 support were detected for the Co/iwi and Co/sc catalysts. Thus, the combination of Co3O4 nanoparticles and Co(II) sites interacting with the siliceous structure, highly dispersed on the surface and inside the mesoporous support obtained by the ‘scfrd’ method resulted in a more active and selective catalyst for the COProx reaction.
      Graphical abstract image

      PubDate: 2016-10-16T22:57:12Z
      DOI: 10.1016/j.micromeso.2016.10.006
      Issue No: Vol. 239 (2016)
       
  • Facile synthesis of amino-functionalized mesoporous TiO2 microparticles
           for adenosine deaminase immobilization
    • Authors: Wei Zhuang; Yuehui Zhang; Linjiao He; Rong An; Bingbing Li; Hanjie Ying; Jinglan Wu; Yong Chen; Jingwei Zhou; Xiaohua Lu
      Pages: 158 - 166
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Wei Zhuang, Yuehui Zhang, Linjiao He, Rong An, Bingbing Li, Hanjie Ying, Jinglan Wu, Yong Chen, Jingwei Zhou, Xiaohua Lu
      Fabrication of biocompatible micro- and nanoparticles is attractive because of their potential for application as enzyme immobilization tools. Mesoporous TiO2 microparticles with high crystallinity, high hydroxyl density, and large pore size (20 nm) were prepared by solid-state calcination and a soft chemistry method. The large pores of the microparticles were efficient in adenosine deaminase (ADA) encapsulation. The hydroxyl-coated microparticles could optimize amino-silane modification and be efficiently utilized as ADA-immobilization carriers. However, the adsorbed enzymes were easily leached when cycled. Sequential application of the coupling agent 3-aminopropyltriethoxysilane and cross-linker glutaraldehyde (GLU) enabled effective ADA coupling. After eight batch cycles, the immobilized ADA retained 80% of its initial activity, much higher than that by direct enzyme adsorption (30%). GLU prevented enzyme desorption and loss of activity. We thus improved ADA loading efficiency, recycling, and stability. TiO2 microparticles could be suitable ADA immobilization candidates for detection and industrial inosinic acid production.
      Graphical abstract image

      PubDate: 2016-10-16T22:57:12Z
      DOI: 10.1016/j.micromeso.2016.09.006
      Issue No: Vol. 239 (2016)
       
  • New bis(oxazoline)–vanadyl complexes, supported by electrostatic
           interaction in Laponite clay, as heterogeneous catalysts for asymmetric
           oxidation of methyl phenyl sulfide
    • Authors: T. Ben Zid; M. Fadhli; I. Khedher; J.M. Fraile
      Pages: 167 - 172
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): T. Ben Zid, M. Fadhli, I. Khedher, J.M. Fraile
      Chiral bis(oxazoline) ligands are used for the first time to promote the enantioselective vanadium-catalyzed oxidation of sulfides with alkyl hydroperoxides. Several bis(oxazoline)-VO complexes have been prepared and supported by cation exchange in Laponite clay. The substituent in the oxazoline ring, and the type of hydroperoxide are relevant parameters that control the activity and selectivity of the resulting catalysts. Tert-butyl hydroperoxide is more reactive but less enantioselective than cumenehydroperoxide, both with the neat and supported VO-bis(oxazoline) complexes. Activities and enantioselectivities obtained with the heterogeneous catalysts are always lower than in solution, and in general better and more consistent results are obtained with box( i Pr) ligand which seems to be also the best chiral auxiliary in homogeneous phase, leading to a modest but significant enantioselectivity of 20% ee in heterogeneous phase and of 28% in homogeneous phase. The recovered of the best catalyst shows a decrease in the catalytic activity and in the enantioselectivity, in agreement with some decomplexation of the chiral ligand, whereas the supported vanadium species remain stable and recoverable.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.09.055
      Issue No: Vol. 239 (2016)
       
  • A facile “polystyrene-dissolving” strategy to hollow periodic
           mesoporous organosilica with flexible structure-tailorability
    • Authors: Lingang Yang; Hongli Guo; Lingzhi Wang; Jinlong Zhang
      Pages: 173 - 179
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Lingang Yang, Hongli Guo, Lingzhi Wang, Jinlong Zhang
      A facile “template dissolving” strategy has been developed for the fabrication of hollow periodic mesoporous organosilica (HPMO) particles with perpendicularly ordered mesopores, where polystyrene (PS) is used as sacrifice template for the generation of hollow cavity. Systematic characterizations including transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and N2 adsorption/desorption analysis clearly reveal that the HPMO particles have an excellent monodispersity with a high specific surface area of 1246.7 m2 g−1, large pore volume of 1.38 cm3 g−1 and uniformly ordered mesopores of 2.48 nm. The pre-encapsulation of a core into PS (SiO2, Fe3O4@SiO2) results in a yolk-shell (Y-S) particle with high tunable shell thickness (30–60 nm) and cavity size (230–450 nm). The magnetically recyclable Fe3O4-YS-PMO was further utilized to adsorb 2, 4-dichlorophenol (2, 4-DCP) and the controlled release of camptothecin (CPT). Up to 81 mg of CPT was loaded per gram of the Fe3O4-YS-PMO particles, followed with a continuously release of 76% within 5 days.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.10.010
      Issue No: Vol. 239 (2016)
       
  • Mango stone biocomposite preparation and application for crystal violet
           adsorption: A mechanistic study
    • Authors: Sidra Shoukat; Haq Nawaz Bhatti; Munawar Iqbal; Saima Noreen
      Pages: 180 - 189
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Sidra Shoukat, Haq Nawaz Bhatti, Munawar Iqbal, Saima Noreen
      Mango stone biocomposite (MSBC) was prepared and employed for the adsorption of crystal violet (CV) dye. Process variables were optimized and maximum dye adsorption of 352.79 mg/g was achieved at pH 8, 0.05 g adsorbent dose, 30 min contact time, 33 °C for dye initial concentration of 400 mg/L. Salt and surfactants pre-treatments of MSBC did not affect the CV adsorption. The CV equilibrium adsorption data followed pseudo second order kinetic model and Langmuir adsorption isotherm. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) revealed that the CV adsorption onto MSBC was an exothermic and spontaneous process. SEM analysis revealed that the surface morphology of dye loaded MSBC was changed significantly and hydroxyl and carbonyl groups were main functional group responsible for CV adsorption onto MSBC. The prepared MSBC also showed recyclable nature and might be potential candidate for dyes removal form textile effluents.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.10.004
      Issue No: Vol. 239 (2016)
       
  • Salt templated synthesis of hierarchical covalent triazine frameworks
    • Authors: Erik Troschke; Sven Grätz; Lars Borchardt; Danny Haubold; Irena Senkovska; Alexander Eychmueller; Stefan Kaskel
      Pages: 190 - 194
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Erik Troschke, Sven Grätz, Lars Borchardt, Danny Haubold, Irena Senkovska, Alexander Eychmueller, Stefan Kaskel
      Covalent triazine framework (CTF-1) materials with hierarchical pore structures have been synthesised using a salt templating approach. As salt templates binary mixtures of ZnCl2 with various alkali chlorides (instead of only ZnCl2) in combination with a modified temperature protocol were utilised. The porosity of salt templated CTF-1 materials was analysed by means of argon physisorption at 87 K. In addition to microporosity, typical for CTF-1, the resulting materials show enhanced mesoporosity and have high total pore volumes of up to 2.1 cm3 g−1. The presented synthetic protocol provides an access to materials combining high nitrogen content, hierarchical pore structure, and high total pore volume, while established CTF syntheses at elevated temperatures used to increase the pore volume in general cause nitrogen loss. These new hierarchical CTFs are very promising cathode materials for lithium-sulphur batteries, where both characteristics (nitrogen content and mesoporosity) are crucial.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.10.002
      Issue No: Vol. 239 (2016)
       
  • Synthesis method for introducing mesoporosity in a faujasitic-like zeolite
           system from a sodium aluminosilicate gel composition
    • Authors: Bo Wang; Prabir K. Dutta
      Pages: 195 - 208
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Bo Wang, Prabir K. Dutta
      We report a facile synthesis method of hierarchical faujasitic structures from a sodium aluminosilicate composition. The critical experimental variable was the removal of water via heat from the aluminosilicate gel during the synthesis process. These gels were used as starting materials for synthesis. With these partially dehydrated gels, extensive zeolite nucleation did occur, and the extent was varied both with the degree of dehydration and the temperature at which the dehydrated sample was maintained. Nanoparticles of FAU and EMT were formed that pack together resulting in external surface areas of 249–259 m2/g. In addition, under certain conditions of crystal growth, sheet like-structures arising from FAU-EMT intergrowths were observed. The interpenetration packing of the nanosheets lead to zeolitic particles with external surface areas in the range of 127–199 m2/g. The pore size distribution varied with sample preparation and ranged from 2 to 100 nm. These samples were characterized by N2 adsorption, X-ray diffraction and electron microscopy. The thermal and hydrothermal stability was also studied. In order to evaluate the role of the higher external surface area on a chemical reaction, the dealkylation of 1,3,5-triisopropylbenzene was examined and the product distribution did reflect the mesoporous nature of the sample.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.10.008
      Issue No: Vol. 239 (2016)
       
  • Silane functionalized open-celled ceramic foams as support structure in
           metal organic framework composite materials
    • Authors: Ulf Betke; Steven Proemmel; Stefan Rannabauer; Alexandra Lieb; Michael Scheffler; Franziska Scheffler
      Pages: 209 - 220
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Ulf Betke, Steven Proemmel, Stefan Rannabauer, Alexandra Lieb, Michael Scheffler, Franziska Scheffler
      The metal organic framework (MOF) materials HKUST-1, CAU-10, MIL-101(Cr) and UiO-66(Zr) were successfully coated onto open cellular silanized alumina and oxide bonded silicon carbide foams by a direct crystallization approach. Two different silanization routes were tested with respect to the functional group of the silane molecule used. For the HKUST-1 and CAU-10 based composite materials the influence of the foam material, its pore size and pore density and its surface chemistry on the amount of deposited MOF material and its water uptake capacity was evaluated. Based on these data in combination with micro computertomograpy results a model was developed to estimate the MOF coating thickness on cellular supports.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.10.011
      Issue No: Vol. 239 (2016)
       
  • A review of adsorbate and temperature-induced zeolite framework
           flexibility
    • Authors: Boris Ilić; Stephanie G. Wettstein
      Pages: 221 - 234
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Boris Ilić, Stephanie G. Wettstein
      It has been known for over 50 years that zeolite frameworks are flexible, yet, until recently, this characteristic has not been exploited. Framework flexibility can have significant implications on the processes that utilize zeolite materials for catalysis, sorption, or, most importantly, separations. The flexibility can result from adsorption and/or temperature changes and leads to either expansion or contraction of the unit cell. These unit cell changes have particularly significant effects on zeolite membranes, enabling defects to be closed off through framework expansion and ultimately leading to membranes with much higher selectivities than as-synthesized membranes. This review provides a general background for zeolite framework flexibility and summarizes the present literature data for adsorbate and thermally-induced flexibility.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.10.005
      Issue No: Vol. 239 (2016)
       
  • Mesoporous silica templated by polyion complex micelles: A versatile
           approach for controlling the mesostructure
    • Authors: Dania Houssein; Jérôme Warnant; Emilie Molina; Thomas Cacciaguerra; Corine Gérardin; Nathalie Marcotte
      Pages: 244 - 252
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Dania Houssein, Jérôme Warnant, Emilie Molina, Thomas Cacciaguerra, Corine Gérardin, Nathalie Marcotte
      The possibility to structure silica materials using polyion complex (PIC) micelles of poly-L-lysine (PLL) and poly(ethylene oxide)-b-poly(acrylic acid) (PEO-b-PAA) as novel structure directing agents was evidenced. More importantly the potential of such polyion complexes to act as versatile systems allowing an easy control of the silica mesostructure was revealed, thus providing materials with adjustable physico-chemical properties. Different mesostructures (lamellar, wormlike) and morphologies (bulk, nanoparticles) were obtained by simply varying the initial composition of the reaction medium, namely the ratio between the two polymers, the amount of silica relative to the polymers and the overall mass concentration, which in turn governed the chemical composition of the obtained hybrid organic/inorganic materials. All the processing parameters-induced mesostructural variations were rationalized with respect to the chemical compositions of the resulting hybrid materials, which were discussed based on competing chemical equilibria between species responsible for the mesostructuring; the results were interpreted in terms of interfacial curvature changes.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.10.013
      Issue No: Vol. 239 (2016)
       
  • Propylsulfonic acid functionalized MCA cubic mesoporous and ZSM-5-MCA
           composite catalysts for anisole alkylation
    • Authors: Siripan Samutsri; Joongjai Panpranot; Duangamol Nuntasri Tungasmita
      Pages: 253 - 262
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Siripan Samutsri, Joongjai Panpranot, Duangamol Nuntasri Tungasmita
      Propylsulfonic acid functionalized mesoporous cubic Ia-3d amorphous (MCA) silica (MCA-Pr-SO3H) was synthesized by co-condensation. Different amounts of ZSM-5 seeds were added into the Ia-3d mesopore silica gel to yield ZM-x composites (where x is the wt.% loading level of ZSM-5). The structure characterization, morphology and acidity of the synthesized materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy and 13C-NMR techniques. The composite materials were found to have properties of both mesoporous (MCA) and ZSM-5, with the ZSM-5 loading level having a major effect on the structure of the Ia-3d mesoporous composite. The MCA-Pr-SO3H catalytic activity in the anisole alkylation reaction with tert-butanol was compared to that of Amberlyst-15, ZSM-5 and ZM-30 materials. The highest yield of total tert-butylated anisole (TBA) products was obtained with MCA-Pr-SO3H, with the major products being 4-tert-butyl anisole (4-TBA), 2-tert-butyl anisole and 2, 4-di-tert-butyl anisole. Compared with the other materials, ZM-30 promoted high selectivity of para-alkylated anisole (4-TBA) and the yield of TBA products.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
      DOI: 10.1016/j.micromeso.2016.10.021
      Issue No: Vol. 239 (2016)
       
  • SBA-15:TiO2 nanocomposites: II. Direct and post-synthesis using
           acetylacetone
    • Authors: Alice A.M.L.F.; Jardim Rebeca Bacani Norberto C.A. Fantini Tereza Martins
      Abstract: Publication date: February 2017
      Source:Microporous and Mesoporous Materials, Volume 239
      Author(s): Alice A.M.L.F. Jardim, Rebeca Bacani, Norberto S. Gonçalves, Márcia C.A. Fantini, Tereza S. Martins
      Nanosized titanium dioxide (TiO2) is used in different applications that require a specific crystalline structure. In this work, SBA-15:TiO2 nanocomposites (80 mol% Si and 20 mol% Ti) were prepared using two different synthesis routes (direct and post-synthesis), with and without acetylacetone and a modified hydrothermal route (M). The small angle X-ray diffraction data showed that all nanocomposites are ordered mesoporous materials. N2 adsorption-desorption analysis showed that the materials exhibit a narrow pore size distribution with mean pore diameters up to 9.9 nm, high surface areas up to 810 m2 g−1 and large pore volumes up to 1.3 cm3 g−1. The analysis of the morphology by scanning electron microscopy (SEM) revealed different particle shapes due to the inclusion of Ti together with the Si source in the direct synthesis route. The characterization by X-ray diffraction revealed that the presence of acetylacetone and the M route in the direct synthesis method favored the formation of the rutile phase (>90%). Additionally, the posterior inclusion of Ti (post-synthesis) favored the formation of single phase anatase (100%). In addition, the SEM images showed that the silica particle size is about 1 μm, thus being biologically safe and making the composite a very promising photoprotector.
      Graphical abstract image

      PubDate: 2016-10-23T14:14:20Z
       
 
 
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