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Journal Cover Microporous and Mesoporous Materials
  [SJR: 1.243]   [H-I: 116]   [9 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1387-1811
   Published by Elsevier Homepage  [3123 journals]
  • Synthesis of mesoporous Ti-inserted SBA-15 and CoMo/Ti-SBA-15 catalyst for
           hydrodesulfurization and hydrodearomatization
    • Authors: Thanh Tung Nguyen; Eika W. Qian
      Pages: 1 - 7
      Abstract: Publication date: 15 July 2018
      Source:Microporous and Mesoporous Materials, Volume 265
      Author(s): Thanh Tung Nguyen, Eika W. Qian
      Ti-inserted ordered mesoporous silica SBA-15 (Ti-SBA-15) synthesized by original microwave-assisted method as a support was used to prepare CoMo catalysts to develop a new catalyst with high hydrodesulfurization (HDS) and controlled hydrodearomatization (HDA) activities. The activity tests of catalysts were carried out by using a pressurized fixed-bed flow reactor. 4,6-Dimethyldibenzothiophene (4,6-DMDBT), 1-methylnaphthalene, and phenanthrene were used as model reactants in HDS and HDA, respectively. CoMo/Ti-SBA-15 catalyst showed about 1.35 times of HDS activity and half of HDA activity of CoMo/SBA-15 catalyst. The results of XRD, FT-IR and 29Si-NMR reveal that titanium was successfully inserted into silica framework of SBA-15, and the SBA-15 mesoporous structure was maintained after insertion of titanium. The reduction of molybdenum from Mo6+ to Mo4+ readily occurred with incorporation of titanium, resulting in an increase in Mo4+ species and CoMoS phase on sulfided catalysts. This enhanced the HDS activity of CoMoTiSBA15 catalyst. Moreover, the presence of Ti3+ on CoMo/Ti-SBA-15 was observed, suggesting that TiMoS was formed and played a role as new active sites. CoMoS active slabs with shorter length and higher stacking layer were formed on CoMo/Ti-SBA-15 comparing with CoMo/SBA-15, resulting in the low HDA activity of the former.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.026
      Issue No: Vol. 265 (2018)
       
  • O-containing hyper-cross-linked polymers and porous carbons for CO2
           capture
    • Authors: Lishu Shao; Siqi Wang; Mingqiang Liu; Jianhan Huang; You-Nian Liu
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Mingqiang Liu, Lishu Shao, Jianhan Huang, You-Nian Liu
      The O-containing hyper-cross-linked polymers were synthesized from phenol (2-naphthol) and formaldehyde dimethyl acetal by a simple one-step Friedel-Crafts reaction, they were subsequently carbonized using KOH as the activating agent, and their adsorption to CO2 was carefully tested. The results indicated that these samples had a high Brunauer-Emmett-Teller surface area (up to 2241 m2/g), pore volume (up to 1.20 cm3/g), CO2 uptake (up to 6.3 mmol/g at 273 K and 1.0 bar), and CO2/N2 selectivity (up to 96 for the HCPs, and 22.5 for the porous carbon). In particular, the CO2 adsorption was highly dependent on the ultramicropore volume (pore width<0.7 nm), while the CO2/N2 selectivity mainly relied on the oxygen content and the ultramicropore structure.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.cej.2018.01.145
      Issue No: Vol. 264 (2018)
       
  • Application of thermoporometry for characterization of mesoporous silicon:
           In search for probe liquid aimed at large pores
    • Authors: D. Majda; T. Ikonen; A. Krupa; V.-P. Lehto; W. Makowski
      Pages: 1 - 7
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): D. Majda, T. Ikonen, A. Krupa, V.-P. Lehto, W. Makowski
      Characterization of porous samples containing mesopores larger than 10 nm in size is often difficult due to limitations of standard methods. In the present work thermoporometry (TPM) was introduced to address these challenges. Various probe liquids (water, n-heptane, cyclohexane and o-xylene) were previously applied for TPM characterization of mesoporous silicon containing pores of 20–50 nm. The results, obtained with the use of calibration equations, confirmed the necessity of new probe liquid more suitable for characterization of such samples. Octamethylcyclotetrasiloxane was found to be the most appropriate choice. Mesoporous silicon samples were used as model materials in order to establish an empirical equation between the pore sizes, derived from mercury porometry, and the solid-liquid transition temperature depressions derived from differential scanning calorimetry for the octamethylcyclotetrasiloxane confined inside the pores and in bulk phase. The new calibration equations obtained within this work can be successfully used for characterization of the samples with large mesopores.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.028
      Issue No: Vol. 264 (2018)
       
  • NaAlH4/microporous carbon composite materials for reversible hydrogen
           storage
    • Authors: Rasmus Palm; Heisi Kurig; Jaan Aruväli; Enn Lust
      Pages: 8 - 12
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Rasmus Palm, Heisi Kurig, Jaan Aruväli, Enn Lust
      Nanoconfinement of NaAlH4 inside a nanoporous carbon material and its effect on the reversible hydrogen storage has been studied. NaAlH4 has been deposited into/onto a highly microporous carbon material by solution impregnation method. The structure of the deposited NaAlH4 and H2 release from NaAlH4 after deposition and after 10 dehydrogenation/hydrogenation cycles has been investigated. Materials with smaller NaAlH4 particles and a higher ratio of amorphous NaAlH4 phase start releasing hydrogen at ambient temperatures (>23 °C). Hydrogen release takes place from nanostructured NaAlH4 with a more even rate over a larger temperature interval. During repetitive cycling, the crystalline NaAlH4 had been converted into amorphous nanoconfined phase or irreversibly decomposed into bulk phases, crystalline Al and Na3AlH6, which have been detected by X-ray diffraction method. Hydrogen release from nanoconfined amorphous NaAlH4 started already at ambient temperatures. Improved reversibility of H2 storage has been demonstrated. The data for nanoconfined material has been compared to bulk NaAlH4.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.027
      Issue No: Vol. 264 (2018)
       
  • Fabrication of highly ordered nanoporous alumina membranes: Probing
           microstructures by SAXS, FESEM and AFM
    • Authors: R. Syed; D. Sen; K.V. Mani Krishna; S.K. Ghosh
      Pages: 13 - 21
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): R. Syed, D. Sen, K.V. Mani Krishna, S.K. Ghosh
      In this study, we report synthesis of highly ordered self-organized nanoporous alumina membranes (NAMs) with two distinct pore diameter ranges by two step anodization technique from two different electrolytes containing simple H2SO4 and mixed electrolyte consisting of H2SO4 and ethylene glycol. Three different complimentary techniques field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and small X-ray scattering (SAXS) were used to characterize the synthesised membranes. An attempt was made to correlate the pore parameters obtained from low ensemble size two dimensional FESEM and AFM micrographs and from large area three dimensional scattering using SAXS. A special attention was given in estimating the porosity of these ordered membranes and compared the results. It was demonstrated that such controlled synthesis method can result in improved pore regularity in NAMs along with enhanced porosity, greater than 40%.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.034
      Issue No: Vol. 264 (2018)
       
  • Thermodynamics, kinetics and selectivity of H2 and D2 on zeolite 5A below
           77K
    • Authors: Renjin Xiong; Rafael Balderas Xicohténcatl; Linda Zhang; Peilong Li; Yong Yao; Ge Sang; Changan Chen; Tao Tang; Deli Luo; Michael Hirscher
      Pages: 22 - 27
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Renjin Xiong, Rafael Balderas Xicohténcatl, Linda Zhang, Peilong Li, Yong Yao, Ge Sang, Changan Chen, Tao Tang, Deli Luo, Michael Hirscher
      Thermodynamics, kinetics and selectivity of H2 and D2 on zeolite 5A have been investigated by isotherm adsorption/desorption and thermal desorption spectroscopy (TDS) at temperatures below 77 K. The experimental adsorption isotherms show an increasing amount of gas adsorbed with decreasing temperature from 77 K to 30 K, and D2/H2 adsorption ratio is slightly larger than 1. In addition, the enthalpy of D2 (ΔH) adsorption obtained from adsorption isotherms is for different uptakes always larger than for H2 indicating a stronger D2 adsorption. The kinetics of H2 adsorption/desorption is faster than of D2 at different temperatures (30–50 K), pressures (10-400 mbar) and gas composition due to the faster H2 self-diffusion in zeolite 5A at low temperature. Furthermore, D2/H2 selectivity increases gradually and reaches a constant value with increasing loading time and pressure, and it is 8.83, 6.42, 4.98, 3.96 and 4.04 at 30, 35, 40, 50 and 60 K at 50 mbar, respectively. The D2/H2 separation in zeolite 5A is controlled by the thermodynamic equilibrium of adsorption under the experimental conditions applied here. To the best of our knowledge, this is the first report on the hydrogen isotope selectivity of zeolite 5A at temperatures below 77 K.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.035
      Issue No: Vol. 264 (2018)
       
  • Synthesis and characterization of porous surface molecularly imprinted
           silica microsphere for selective extraction of ascorbic acid
    • Authors: Rafael S. Fernandes; Mehmet Dinc; Ivo M. Raimundo; Boris Mizaikoff
      Pages: 28 - 34
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Rafael S. Fernandes, Mehmet Dinc, Ivo M. Raimundo, Boris Mizaikoff
      Molecularly imprinted polymers (MIPs) with core-shell structure for efficient, reliable, and selective extraction of ascorbic acid (AA) were developed via co-polymerization process based on acrylamide (AM) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linker, 2,2'-azobis(2-methylpropionitrile) (AIBN) as initiator, and AA as template. The inorganic core comprised of amino-functionalized silica microspheres (AFSM) was prepared by co-condensation of tetraethylorthosilicate (TEOS) and (3-aminopropyl)trimethoxysilane) (APTMS) in a water-in-oil (W/O) macroemulsion. The synthesized materials were characterized by IR-ATR, SEM, and N2 adsorption–desorption isotherm. The binding properties and selectivity of the AFSM@MIP and AFSM@NIP (i.e., non-imprinted polymers) were demonstrated by adsorption capacity and imprinting factor obtained based on UV–Vis absorption measurements. Furthermore, synthesis conditions were optimized such that imprinting efficiency and adsorption capacity were maximized. Finally, it was demonstrated that generated MIP core-shell hybrid microspheres provide rapid adsorption with high binding capacities (up to 5.08 mg g−1), excellent imprint factors, and exceptional reusability. A comparative study using AFSM@MIP and AFSM@NIP for simultaneous extraction of AA and citric acid (CA), allowed verifying the excellent selectivity of AFSM@MIP, which presented an imprinting factor of 2.30.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.07.019
      Issue No: Vol. 264 (2018)
       
  • Facile synthesis of Cd-substituted zeolitic-imidazolate framework Cd-ZIF-8
           and mixed-metal CdZn-ZIF-8
    • Authors: Jingze Sun; Liya Semenchenko; Woo Taik Lim; Maria Fernanda Ballesteros Rivas; Victor Varela-Guerrero; Hae-Kwon Jeong
      Pages: 35 - 42
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Jingze Sun, Liya Semenchenko, Woo Taik Lim, Maria Fernanda Ballesteros Rivas, Victor Varela-Guerrero, Hae-Kwon Jeong
      Zeolitic-imidazole framework ZIF-8 has attracted tremendous interests for the high-resolution kinetic separation of propylene/propane mixture due to its effective aperture size in between the sizes of propylene and propane molecules. It is of great interest to fine-tune the effective aperture size of ZIF-8 either to improve its propylene/propane separation performances or to extend its use to the separation of other gas mixtures. It has been shown that substituting Zn with other metal nodes (e.g. Co) is a potential means to fine-tune the effective aperture size of ZIF-8. Here, we attempt to introduce another metal center, Cd, into ZIF-8 in a facile and scalable manner. Phase-pure Cd-ZIF-8 was successfully synthesized in methanol using a conventional solvothermal method, although it showed a narrow synthesis window. The presence of an organic base (triethylamine, TEA) was found critical not only for the facile synthesis of phase-pure Cd-ZIF-8 but also for the suppression of its phase transformation. A battery of characterizations including single-crystal X-ray structure solutions confirmed that the effective aperture size of Cd-ZIF-8 is the largest among its iso-structures (Zn-ZIF-8 and Co-ZIF-8). Finally, for the first time, mixed-metal CdZn-ZIF-8 crystals with various Cd/Zn ratios were solvothermally synthesized, demonstrating a further opportunity for varying the effective aperture sizes of ZIF-8 and its iso-structures.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.032
      Issue No: Vol. 264 (2018)
       
  • Oil-in-water synthesis of hollow-shell mesoporous peapod-like silicates:
           Electron microscopy insights
    • Authors: V. Morales; M. Pérez-Garnes; M. Balabasquer; J. González-Casablanca; R.A. García-Muñoz
      Pages: 43 - 54
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): V. Morales, M. Pérez-Garnes, M. Balabasquer, J. González-Casablanca, R.A. García-Muñoz
      Hollow mesoporous silica nanoparticles (HMSN) receive a remarkable attention for their many advantages in several applications. Hollow-shell mesoporous peapod-like silicates were synthesized based on the recently introduced drug structure-directing agent (DSDA) concept. The anionic DSDA was formed by the amidation of L-tryptophan with palmitoyl chloride. 3-Aminopropyltrimethoxysilane (APS) was employed as co-structure directing agent (CSDA). The interactions among DSDA, CSDA and silica source promoted the formation of the oil-in-water emulsions. We hypothesized that the emulsions aggregated in micelles that merged into sheet-like structures that curved, bent and closed to form spherical hollow structures. Finally, the hollow structures fused between them to form the final hollow-shell peapod-like silicates with 0.6–2.5 μm in length. Interestingly, the formation of inner lamellar-like mesoporous pillars separated by large mesovoids with sizes around 50 nm was promoted. The role of the APS is determinant in the synthesis of the hollow morphologies, since its absence disrupts the formation of HMSNs. The changes in the organic component packing and the charge density matching between the silica framework, continuously transforming, and the surfactant headgroups are postulated as the driving forces in determining the particles morphology. Moreover, based on an original TEM sample preparation, perpendicular views over the long axis, and mainly over the short axis were acquired, proving the symmetry of revolution of these materials along their axis. Perpendicular slices of the nanoparticles demonstrated the internal hollows and the inner crossing walls with lamellar-like mesoporosity. These materials are expected to have potential applications in fields including, batteries, adsorption, and mainly in biomedicine processes.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.005
      Issue No: Vol. 264 (2018)
       
  • Probing locations of organic structure-directing agents (OSDAs) and
           host-guest interactions in CHA-type SAPO-34/44
    • Authors: Nana Yan; Hongyi Xu; Wenna Zhang; Tantan Sun; Peng Guo; Peng Tian; Zhongmin Liu
      Pages: 55 - 59
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Nana Yan, Hongyi Xu, Wenna Zhang, Tantan Sun, Peng Guo, Peng Tian, Zhongmin Liu
      In this work, we have synthesized four SAPO-34/44 (framework type code: CHA) samples by utilizing different organic structure-directing agent (OSDA) such as cyclohexylamine (CA), n-butylamine (BA), diisopropylamine (DIPA), and dipropylamine (DPA). An approach combining Rietveld refinement and simulated annealing has been successfully applied to determine the location of the individual OSDA and the host (inorganic framework)-guest (OSDA) interaction. The final Rietveld refinements show that 1) one cha cage can be occupied by either two OSDAs (CA and BA) in the up-and-down arrangement or one OSDA (DIPA and DPA) in the longitudinal configuration and 2) the classical hydrogen bond between CA/BA and the inorganic framework in SAPO-44-CA and SAPO-34-BA could be identified. The host-guest interactions among these four samples are also investigated by FT-IR, which are consistent with Rietveld refinement results. The approach employed here could be applicable for the host-guest investigation in other crystalline porous materials.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.002
      Issue No: Vol. 264 (2018)
       
  • The Lifshitz-van der Waals acid-base theory assisted fabrication of
           MFI-containing mixed matrix membranes for gas separations
    • Authors: Sunghwan Park; Eunhee Jang; Heseong An; Wansuk Choi; Jeong-Hoon Kim; Jung-Hyun Lee; Jungkyu Choi; Jong Suk Lee
      Pages: 60 - 69
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Sunghwan Park, Eunhee Jang, Heseong An, Wansuk Choi, Jeong-Hoon Kim, Jung-Hyun Lee, Jungkyu Choi, Jong Suk Lee
      A zeolite-containing mixed matrix membrane (MMM) is an attractive option to overcome the performance limits of polymeric membranes for large-scale gas separations. The poor interfacial adhesion between zeolites and polymers, however, should be addressed to realize the excellent separation performance of zeolites on large industrial scale. Herein, the interfacial void-free MMMs with incorporation of intact MFI type zeolite particles were successfully prepared by applying the Lifshitz-van der Waals acid-base theory for the selection of the appropriate polymer matrix. Our simple, but systematic approach was based on the adhesion force between MFI particles and a surrounding polymer matrix. The relatively high Lewis basicity of cellulose acetate (CA) leads to highest adhesion force with MFI particles among the tested polymer matrices, suppressing interfacial void formation. In addition, a careful analysis revealed that any residual surfactants on the surface of MFI particles are detrimental to fabricate interfacial void-free MMMs. Single gas (i.e. N2 and NF3) transport in the CA/MFI MMMs were characterized by changing the concentration of MFI particles up to 30 wt%. N2 permeability of CA/MFI MMMs was improved by as much as 304% compared to that of bare CA membranes with maintaining N2/NF3 permselectivity. Furthermore, gas transports in CA/MFI MMMs by varying the size of MFI particles from 0.2 through 0.6 up to 1.5 μm were analyzed by using the Lewis-Nielsen model. Our systematic theory-based guidance can be utilized to offer the appropriate polymer candidates for the zeolite-containing MMMs for high performance gas separations.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.006
      Issue No: Vol. 264 (2018)
       
  • Relation of water adsorption capacities of zeolites with their structural
           properties
    • Authors: Melkon Tatlier; Gunther Munz; Stefan K. Henninger
      Pages: 70 - 75
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Melkon Tatlier, Gunther Munz, Stefan K. Henninger
      An investigation was carried out to determine the extent of relations between various structural properties of zeolite frameworks and their experimental water adsorption capacities. For this aim, average water capacity values were determined for different zeolite frameworks by utilizing water adsorption capacities reported in the literature for related materials. It was observed that the theoretical surface areas and volumes available for water adsorption in zeolites as well as the fractal dimensions of these materials exhibited some correlation with their experimental adsorption capacities. The results might give an indication of the potential for development of different zeolite frameworks, regarding their water adsorption capacities. Analogue materials of known zeolite framework structures, with different chemical compositions, which may allow for relatively high water adsorption capacities, may be prepared for such an improvement. The investigations may also be informative for the development of new zeolite-like adsorbents with relatively high capacities.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.031
      Issue No: Vol. 264 (2018)
       
  • Decoding gas-solid interaction effects on adsorption isotherm shape: I.
           Non-polar adsorptives
    • Authors: S. Hadi Madani; Phillip Kwong; Francisco Rodríguez-Reinoso; Mark J. Biggs; Phillip Pendleton
      Pages: 76 - 83
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): S. Hadi Madani, Phillip Kwong, Francisco Rodríguez-Reinoso, Mark J. Biggs, Phillip Pendleton
      A suite of non-polar adsorptives of different kinetic diameters and shape were used to determine adsorption and pore filling mechanism of a well-characterised poly(furfuryl alcohol)-based activated carbon. Triplicate measured Type I adsorption isotherms for each adsorptive were averaged to provide standard deviation in relative pressures and associated amounts adsorbed. Plateau amounts adsorbed for N2, Ar, CH4, and C6H6, provided Gurvitsch volumes averaged to 0.368 ± 0.015 cm3(liq)/g. The calculated Gurvitsch volumes were compared with those derived via the Dubinin-Radushkevich (DR) equation. Additional adsorptives were CO2, iso-butane and SF6. The results of these 7 adsorptives were used to qualitatively analyse and decode a micropore filling adsorption mechanism. The DR equation was also used for further analysis of the pore filling mechanism. Based on the adsorbate-adsorbate and adsorbate-adsorbent interactions, adsorbates were classified into three groups: (a) Non-polar with non-specific interactions (no dipole, no quadrupole, not readily polarizable: Ar, N2, CH4 and iso-butane), adsorbing as a continuous uptake over the observed relative pressure range; (b) Non-polar adsorptives with potential for specific interactions (no dipole, quadrupole moment: CO2 and C6H6), adsorbing as a condensation process over a relatively narrow relative pressure range in a medium pressure range; (c) Halogenated adsorptives (no dipole, no quadrupole, polarizable: SF6), adsorbing with an S-shaped uptake extending over a relatively broad relative pressure range.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.010
      Issue No: Vol. 264 (2018)
       
  • Refractive index and scattering of porous TiO2 films
    • Authors: S. Abdellatif; P. Sharifi; K. Kirah; R. Ghannam; A.S.G. Khalil; D. Erni; F. Marlow
      Pages: 84 - 91
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): S. Abdellatif, P. Sharifi, K. Kirah, R. Ghannam, A.S.G. Khalil, D. Erni, F. Marlow
      Porous titanium dioxide (TiO2) films are essential components of dye sensitized solar cells (DSSCs) as well as perovskite solar cells (PSCs). Unfortunately, porosity, refractive index, and scattering properties of these films are only roughly known. This induces uncertainties in modelling and understanding of these solar cells. Since the literature provides only descriptions of the optical properties of the porous TiO2 layers with unclear relevance to these solar cells, we investigate porous TiO2 films really used in DSSCs and potentially usable in PSCs. The effective refractive index and the film porosity for different nanostructures that were fabricated from solution-based techniques were determined. The found values are 1.7982 ± 0.005 for the effective refractive index of one kind of TiO2 films and 1.62 ± 0.002 for another one. These values lead to porosities of 53.5% and 65%, respectively. The scattering of the films can be described by a wavelength-independent effective scattering parameter for one film type and by effective scattering particles with a diameter of 46.5 nm for the other film type. The determined porosities are also of relevance for the ionic transport which is functionally crucial in DSSCs and a disturbance in PSCs.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.011
      Issue No: Vol. 264 (2018)
       
  • Efficient assembly of hierarchical NaY aggregates by using an organosilane
           modified SDA
    • Authors: Xiaomeng Zhao; Xiaoling Meng; Yunshan Shang; Yu Song; Rugeng Liu; Jianhui Wei; Yanjun Gong; Zhihong Li
      Pages: 92 - 103
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Xiaomeng Zhao, Xiaoling Meng, Yunshan Shang, Yu Song, Rugeng Liu, Jianhui Wei, Yanjun Gong, Zhihong Li
      We demonstrate an efficient method for the assembly of hierarchical NaY aggregates by using a modified structure-directing agent (SDA) in an extremely dense aqueous system at 373K. By introducing the dimethylhexadecyl[3-(trimethoxysilyl)propyl] ammonium chloride (TPHAC) into the aluminosilicate sol, an organo-modified sol was formed and after ageing it was used as SDA in the feedstock gel to generate the well-aligned hierarchical NaY aggregates. The structure evolution of sol and formation of NaY aggregates were systematically investigated by FT-IR, XRD, SEM, TEM and synchrotron radiation small angel X-ray scattering (SR-SAXS), which confirmed the dominant impact of the organosilane on the aluminosilicate species and further on the outcome of the NaY aggregates. The results show that by adding the minimal amount of TPHAC in the sol, the sol promotes long period structure, forming a large amount of aluminosilicate species with suitable size and distribution, which are responsible for tuning the morphology and properties of NaY aggregates under the dense synthetic system. The typical NaY aggregate has high SiO2/Al2O3 of 5.3, consisting of particles (2–4 μm) orderly assembled from 20 to 80 nm crystalline domains of NaY zeolites with high pore volume of 0.43 cm3/g and external surface area of 100 m2/g. The morphology, crystal sizes, mesopore sizes, volume ratios of mesopore/micropore of NaY aggregate can be adjusted by varying the amount of TPHAC, the reaction time and solid content in the dense system. The new insight into regulating sol species structure by TPHAC and forming NaY crystal aggregates were discussed.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.009
      Issue No: Vol. 264 (2018)
       
  • Synthesis of novel nanoporous metal-organic gels with tunable porosity and
           sensing of aromatic compounds
    • Authors: Sokhrab B. Aliev; Stanislav I. Gurskiy; Valery N. Zakharov; Leonid М. Кustov
      Pages: 112 - 117
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): Sokhrab B. Aliev, Stanislav I. Gurskiy, Valery N. Zakharov, Leonid М. Кustov
      Herein we report the bottom up design of novel porous metal-organic gels (MOGs) Fe-ndc (H2ndc – 2,6-naphthalene dicarboxylic acid) and Fe-btc (H4btc - 1,2,4,5-benzenetetracarboxylic acid) based on Fe3+. The effective strategy to obtain MOGs with controllable porosity by changing the concentrations of precursors was studied. The MOGs were dried in vacuum and the resultant xerogels were fully characterized using PXRD, TGA, FT-IR spectroscopy and SEM techniques. The resultant materials demonstrated a wide range of BET surface area 0–290 m2/g. Presence of micro (<2 nm), meso (2–50 nm) and macropores (>50 nm) in obtained xerogels was found. Furthermore, Fe-ndc demonstrated strong dependence of photoluminescence properties on the nature of the guest molecules. A unique enhancement effect of maximum luminescence intensity of the host framework Fe-ndc in the presence of toluene (862%). Introduction of benzene led to just 42% increase of luminescence intensity of material compared to Fe-ndc. Quenching effects of maximum luminescence intensity of the host framework upon introduction of nitrobenzene (67%) and 1,3-dinitrobenzene (46%) were found. These features make Fe-ndc an efficient fluorescent material for selective detection of hazardous highly energetic aromatic compounds.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.001
      Issue No: Vol. 264 (2018)
       
  • A mild conditions synthesis route to produce hydrosodalite from kaolinite,
           compatible with extrusion processing
    • Authors: A. Marsh; A. Heath; P. Patureau; M. Evernden; P. Walker
      Pages: 125 - 132
      Abstract: Publication date: 1 July 2018
      Source:Microporous and Mesoporous Materials, Volume 264
      Author(s): A. Marsh, A. Heath, P. Patureau, M. Evernden, P. Walker
      Hydrosodalites are a family of zeolitic materials which have a diverse range of possible applications such as water desalination. Typical synthesis methods are relatively complex, using hydrothermal production and pre-processing and it is desirable to use lower energy and more cost-effective processing routes. For the first time, a low temperature, non-hydrothermal synthesis procedure for hydrosodalites, compatible with extrusion processing, is demonstrated. Kaolinite precursor, without calcination, was activated with a sodium hydroxide solution and formed at a workability consistent with extrusion. The cured samples were characterised using a range of advanced analytical techniques including PXRD, SEM, TGA, 27Al and 29Si-MAS-NMR, and FTIR to confirm and quantify conversion of the precursor to product phases. The synthesis consistently formed a 8:2:2 basic hydroxysodalite phase and the reaction was shown to follow a largely linear relationship with Na:Al until full conversion to the hydrosodalite phase was approached. The hydrosodalite became more ordered for Na:Al ≥ 1. There is good agreement between quantitative measurements made using PXRD, TGA and 29Si-MAS-NMR methods, providing confidence in the results. It has been shown that it is possible to synthesise hydrosodalite materials in a consistent and predictable manner, using non-hydrothermal methods, at the viscosity used for extrusion processing. This novel processing route could reduce production costs, production impacts and open up new applications for this important family of materials.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.014
      Issue No: Vol. 264 (2018)
       
  • Highly selective adsorption of dyes and arsenate from their aqueous
           mixtures using a silica-sand/cationized-starch composite
    • Authors: Pei Li; Boqiang Gao; Aimin Li; Hu Yang
      Pages: 210 - 219
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Pei Li, Boqiang Gao, Aimin Li, Hu Yang
      A novel composite adsorbent (ST-CTA-SS) composed of starch-3-chloro-2-hydroxypropyl triethyl ammonium chloride (ST-CTA) and micro silica-sand (SS) was prepared simply, with the characteristics of environmental-friendliness and low cost. A variety of techniques were used for characterizing the surface morphology, molecular structure, and settleability of this composite adsorbent. ST-CTA-SS was applied to the removal of arsenate [As(V)] and two anionic dyes, acid green 25 (AG25) and methyl orange (MO), from water in respective single and two metal-dye binary systems. ST-CTA-SS shows a marked improvement of the adsorption capacities for the aforementioned three pollutants, which is attributed to the prominent composited structure compared with ST-CTA without SS. The adsorption capacities of ST-CTA-SS for AG25, MO, and As(V) are up to approximately 912.6 ± 44.6, 458.7 ± 21.3, and 76.63 ± 3.53 mg g−1, respectively, and the adsorption saturations for those three pollutants are all achieved within 20 min. Moreover, this composite adsorbent always exhibited highly selective adsorption of dyes, either MO or AG25, over As(V) from their aqueous mixtures. After saturated adsorption, ST-CTA-SS could be rapidly settled and separated from water due to the imbedded SS, which could be easily regenerated by dilute NaOH solutions. This starch-based composite adsorbent thus owns significant application potentials in water treatment.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.025
      Issue No: Vol. 263 (2018)
       
  • Effect of Cu and Zn ion-exchange locations on mordenite performance in
           dimethyl ether carbonylation
    • Authors: Allen A.C. Reule; Vinay Prasad; Natalia Semagina
      Pages: 220 - 230
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Allen A.C. Reule, Vinay Prasad, Natalia Semagina
      Cu2+ and Zn2+ ion-exchange locations in mordenite (MOR) were evaluated using infrared spectroscopy, pore-size distribution, and temperature-programmed reduction. Isolated copper ions were the most abundant ion-exchanged species, as detected by UV-vis spectroscopy, in addition to oxide nanoparticles, with no presence of binuclear species, which was assigned to a low copper loading of 0.3 Cu/Al. The characterization revealed that only zinc could exchange in 8-membered rings. Hartree-Fock modeling confirmed copper exchange into 12-membered rings involving at least one T1 atom, and zinc exchange in T4 sites and in 8-membered structures, including T3 sites. Copper ion exchange did not offer improvement in the dimethyl ether carbonylation rate or selectivity over acidic mordenite. Zinc ion exchange led to the selectivity and stability improvement with some loss of activity. This work contributes to the understanding of acid and metal site contribution to DME carbonylation and contributes to the understanding for Cu2+ and Zn2+ ion-exchange locations in MOR with a low metal/Al loading (<0.2).
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.026
      Issue No: Vol. 263 (2018)
       
  • Simulating the effect of the quadrupole moment on the adsorption of
           nitrogen in siliceous zeolites
    • Authors: Cannon Hackett; Karl D. Hammond
      Pages: 231 - 235
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Cannon Hackett, Karl D. Hammond
      Physical adsorption of an inert gas such as nitrogen or argon is commonly used to characterize zeolites and other porous materials. In high-resolution adsorption (adsorption in micropores), it has long been known that nitrogen begins to adsorb at a substantially lower relative pressure than argon, despite the similar sizes of the two absorbates. The standard explanation for this difference in relative pressure is that nitrogen has a quadrupole moment, which strengthens its interactions with the zeolite framework atoms, whereas argon does not. In this study, we investigate this standard explanation by simulating the adsorption of nitrogen at 77 K and argon at 87 K in siliceous zeolites of framework types LTA, FAU, and MFI using grand canonical Monte Carlo. For nitrogen, we tested models with a quadrupole formed by three collinear point charges, as well as models in which the effect of the quadrupole moment was removed by setting the point charges to zero. We find that the influence of the quadrupole moment is heavily dependent on the magnitude of the zeolite framework charges in the model. For a model with relatively weak framework charges, the quadrupole moment makes very little difference, but with stronger framework charges, nitrogen with its quadrupole moment begins to adsorb at much lower pressures than nitrogen without its quadrupole moment, accounting for most of the spread between nitrogen and argon. Since the larger-magnitude charges we studied are more in line with theoretically-derived values, we conclude that the standard explanation is largely correct. We recommend that zeolite models use partial charges with reasonable theoretical justification and that are checked against the accuracy of simulations of adsorption of quadrupolar gases.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.018
      Issue No: Vol. 263 (2018)
       
  • Structural investigations in pure-silica and Al-ZSM-12 with MTEA or TEA
           cations
    • Authors: Marta Počkaj; Anton Meden; Nataša Zabukovec Logar; Mojca Rangus; Gregor Mali; Ines Lezcano-Gonzalez; Andrew M. Beale; Amalija Golobič
      Pages: 236 - 242
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Marta Počkaj, Anton Meden, Nataša Zabukovec Logar, Mojca Rangus, Gregor Mali, Ines Lezcano-Gonzalez, Andrew M. Beale, Amalija Golobič
      Two different quaternary ammonium cations, methyltriethyl- (MTEA) and tetraethylammonium cations (TEA) were used as templates in the synthesis of pure-silica as well as aluminosilicate ZSM-12 (MTW-type) frameworks. The distribution of the template cations in the 12-membered rings channels in the 1-dimensional framework topology was studied; thus the as-prepared products were characterized by means of X-ray powder diffraction, Raman, transmission FTIR, solid-state NMR spectroscopy, thermogravimetric and elemental analyses and SEM. It was shown that in pure-silica (PS) ZSM-12, TEA cations are well ordered - a superstructure with three-times longer b edge (in comparison to unit cell of empty framework) along the channel is formed, which can be seen by virtue of a few additional peaks in the X-ray powder pattern. Herein we describe that its aluminosilicate counterpart with TEA also contains ordered TEA cations and is isostructural to PS-ZSM-12. Conversely, in both pure-silica and aluminosilicate ZSM-12 frameworks with MTEA, the cations are disordered and no superstructure is formed.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.015
      Issue No: Vol. 263 (2018)
       
  • Conversion of methanol to light olefins over nanosized [Fe,Al]ZSM-5
           zeolites: Influence of Fe incorporated into the framework on the acidity
           and catalytic performance
    • Authors: Xin Jiang; Xiaofang Su; Xuefeng Bai; Yuzong Li; Lan Yang; Ke Zhang; Yang Zhang; Yang Liu; Wei Wu
      Pages: 243 - 250
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Xin Jiang, Xiaofang Su, Xuefeng Bai, Yuzong Li, Lan Yang, Ke Zhang, Yang Zhang, Yang Liu, Wei Wu
      Nanosized ZSM-5 zeolites (NZ5(x) series) with different SiO2/Al2O3 ratios as well as samples isomorphously substituted by Fe ([Fe,Al]NZ5(x) series) with various SiO2/(Al2O3+Fe2O3) ratios were synthesized by an in situ seed-induced hydrothermal method. The structure, morphology, textural and acidity of catalysts were characterized via XRD, SEM, 27Al and 29Si MAS NMR, UV–vis spectroscopy, XPS, N2 physical adsorption, NH3-TPD and Py-IR. The catalytic performance was assessed by methanol-to-olefins (MTO) reaction and the effect of the textural and acidity of the two series of samples on the catalytic performance was also investigated. The results showed that the catalyst acidity is closely related to the product selectivity in the MTO reaction. Compared with NZ5(x), the [Fe,Al]NZ5(x) samples with smaller particle size, weaker acid strength and fewer Brønsted acid sites displayed a higher selectivity towards C2∼C4 light olefins. Highest selectivity of 82.7% for C2∼C4 light olefins and lowest coke amount of 0.71% after reaction for 50 h was obtained for the [Fe,Al]NZ5(300) catalyst due to the appropriate acidity and improved diffusion properties.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.029
      Issue No: Vol. 263 (2018)
       
  • ZSM-5 synthesis by the assistance of biomass and biomass-derivate
           compounds
    • Authors: Elisa S. Gomes; Donato A.G. Aranda; Marcelo M. Pereira; Benoît Louis
      Pages: 251 - 256
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Elisa S. Gomes, Donato A.G. Aranda, Marcelo M. Pereira, Benoît Louis
      ZSM-5 zeolites with tailored properties were successfully synthesized in the presence of biomass-derivative compounds following conventional hydrothermal route. The strategy consisted of introducing, along with silica and alumina precursors, either sugar cane bagasse itself or biomass-derivate compounds obtained by hydrolysis of the sugar cane. As-prepared ZSM-5 catalysts were thoroughly characterized by XRD, XRF, SEM, nitrogen sorption and H/D isotope exchange techniques. The catalysts were evaluated both in the cracking of n-hexane and the methanol conversion into hydrocarbons. Our approach yielded solely ZSM-5 phase with broad differences in their intrinsic properties: external surface area (between 51 and 153 m2 g−1); 8 < Si/Al < 29, thus leading up to high Brønsted acid sites density; crystal size (from 0.3 to 13 μm) and peculiar morphologies. The high Al-content ZSM-5 led to achieve the higher n-hexane cracking activity. The ZSM-5 with the highest external area and higher Si/Al (SAR) converted methanol mainly into light olefins, whilst, the ZSM-5 material with the lower external area and lower SAR yielded gasoline formation.
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.022
      Issue No: Vol. 263 (2018)
       
  • Mixed matrix membrane of ZSM-5/poly (ether-block-amide)/polyethersulfone
           for pervaporation separation of ethyl acetate from aqueous solution
    • Authors: Mostafa Vatani; Ahmadreza Raisi; Gholamlreza Pazuki
      Pages: 257 - 267
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Mostafa Vatani, Ahmadreza Raisi, Gholamlreza Pazuki
      The ZSM-5/poly (ether-block-amide) (PEBA)/polyethersulfone (PES) dual layer mixed matrix membranes (MMMs) were prepared for pervaporation (PV) separation of ethyl acetate (EAc) from aqueous solutions. The ZSM-5 zeolite nanoparticles were synthesized by the conventional hydrothermal method and characterized using the XRD, XRF and FESEM analysis. The effect of top layer thickness, PEBA concentration, zeolite loading concentration, feed concentration and temperature on the separation performance of the prepared membranes was investigated. The FTIR, SEM, contact angle and swelling tests were used to characterize the fabricated MMMs. The results indicated that loading ZSM-5 zeolite nanoparticles into the PEBA matrix had a significant influence on the separation performance of the prepared membranes. The ZSM-5/PEBA/PES membrane containing 7.5 wt% ZSM-5 with a top layer thickness of 20 μm, showed the highest separation factor. The total flux was decreased by loading ZSM-5 into the membranes up to 7.5 wt% and further enhancement in the zeolite loading content resulted in increasing the total permeation flux. The best separation factor and total flux of the ZSM-5/PEBA/PES-07.5 membrane were found to be 108.52 and 1895 g m−2h−1, respectively for a feed concentration of 5 wt% EAc and temperature of 50 °C.
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      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2017.12.030
      Issue No: Vol. 263 (2018)
       
  • MOF@SiO2 core-shell composites as stationary phase in high performance
           liquid chromatography
    • Authors: Sebastian Ehrling; Christel Kutzscher; Pascal Freund; Philipp Müller; Irena Senkovska; Stefan Kaskel
      Pages: 268 - 274
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Sebastian Ehrling, Christel Kutzscher, Pascal Freund, Philipp Müller, Irena Senkovska, Stefan Kaskel
      Mesoporous silica spheres were functionalized with microporous metal-organic frameworks (MOFs), namely MIL-101(Fe)_NH2 (Fe3(O)(BDC_NH2)3(OH)(H2O)2, BDC = benzene-1,4–dicarboxylate) and UiO-67 (Zr6O4(OH)4(BPDC)6, BPDC = 4,4′-biphenyldicarboxylate) to produce core-shell particles for application as stationary phase in high performance liquid chromatography (HPLC) columns using a layer-by-layer method. The composites were studied for application as stationary phase in normal phase HPLC for separation of C8-isomers, dichlorobenzene isomers, styrene and ethylbenzene. Both silica/MOF composites show the highest affinity towards the ortho substituted analytes, indicating that the selectivity is dominated by the polarity of the analytes. Moreover, the UiO-67@SiO2 composite shows high separation efficiency in the separation of dimethyl phthalate and diethyl phthalate, since the number of theoretical plates per meter is very high (37570 m−1).
      Graphical abstract image

      PubDate: 2018-02-05T09:31:21Z
      DOI: 10.1016/j.micromeso.2018.01.003
      Issue No: Vol. 263 (2018)
       
  • Overgrowth of lamellar silicalite-1 on MFI and BEA zeolites and its
           consequences on non-oxidative methane aromatization reaction
    • Authors: Yiqing Wu; Laleh Emdadi; Emily Schulman; Yuying Shu; Dat T. Tran; Xizheng Wang; Dongxia Liu
      Pages: 1 - 10
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Yiqing Wu, Laleh Emdadi, Emily Schulman, Yuying Shu, Dat T. Tran, Xizheng Wang, Dongxia Liu
      The combination of two compositionally and/or structurally different zeolites into one single zeolite composite particle is a potential approach to integrate advantages of different zeolite structures for desirable properties and applications. In the present study, we report the overgrowth of lamellar mesoporous silicalite-1 on the commercial microporous MFI and BEA zeolites, respectively, to render hierarchical meso-/microporous lamellar silicalite-1/MFI (L-Si/MFI) and lamellar silicalite-1/BEA (L-Si/BEA) zeolite composites via hydrothermal crystallization of lamellar silicalite-1 with the assistance of a diquaternary ammonium template. Epitaxial growth of lamellar silicalite-1 on commercial bulk MFI was observed, resulting in the L-Si/MFI zeolite composite as porcupine sensory message ball with nerve-stimulating silicalite-1 bumps extended from the MFI particle. In the L-Si/BEA zeolite composite, the lamellar silicalite-1 was laid over the surface of or partially interdigitated into the commercial bulk BEA particle, forming a BEA nanosponge structure connected to lamellar silicalite-1 nanosheets. The resultant interconnected micro- and mesoporosity in the L-Si/MFI and L-Si/BEA composite zeolites allowed facile mass transport of bulky molecules. The acid sites sitting on the external surface of commercial MFI and BEA zeolites were partially passivated by the lamellar silicalite-1. The consequences of improved mass transport and passivation of external acid sites on the catalytic performance of these zeolite composites were tested in 2 wt% molybdenum (Mo) loaded L-Si/MFI and L-Si/BEA for direct non-oxidative methane aromatization reaction, which showed higher methane conversion and hydrocarbon product formation as well as higher selectivity to naphthalene and coke in comparison with 2 wt% Mo-loaded commercial MFI and BEA catalysts.
      Graphical abstract image

      PubDate: 2017-12-12T08:22:26Z
      DOI: 10.1016/j.micromeso.2017.11.040
      Issue No: Vol. 263 (2017)
       
  • Fast preparation of ERI-structure AlPO-17 and SAPO-17 in the presences of
           isomorphous and heterogeneous seeds
    • Authors: Shenglai Zhong; Shichao Song; Bin Wang; Na Bu; Xiaobin Ding; Rongfei Zhou; Wanqing Jin
      Pages: 11 - 20
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Shenglai Zhong, Shichao Song, Bin Wang, Na Bu, Xiaobin Ding, Rongfei Zhou, Wanqing Jin
      Pure-phase ERI-structure AlPO-17 and SAPO-17 crystals were prepared using isomorphous (AlPO-17) and heterogeneous (zeolite T, SSZ-13 and SAPO-34) seeds. These heterogeneous seeds acts as the sole silica source for SAPO-17 preparation in most of cases. Crystallization mechanism of SAPO-17 and phase transformation process were demonstrated. On contract, SAPO-17 with impurity phases were obtained by in-situ synthesis. Seeded growth using the two kinds of seeds enhanced the crystallization rates by factors of 10–30 compared with in-situ synthesis. Physicochemical properties and Si, Al and P chemical environments of the products were characterized using X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption, thermogravimetric analysis, inductively coupled plasma elementary analysis, magic-angle-spinning solid-state NMR spectroscopy and temperature-programmed NH3 desorption. Synthesis of SAPO-17 with all Si in isolated state demonstrated that SAPO-17 crystallization proceeded by a dissolution-construction mechanism. It included twice phase conventions: dissolved silica-rich zeolites inducing the formation of AFI-structure SAPO-5 and AFI structure converting to ERI framework.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.11.034
      Issue No: Vol. 263 (2017)
       
  • The effect of Co and N of porous carbon-based materials fabricated via
           sacrificial templates MOFs on improving DA and UA electrochemical
           detection
    • Authors: Hailing Guo; Mei Wang; Lei Zhao; Nuerguli Youliwasi; Chenguang Liu
      Pages: 21 - 27
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Hailing Guo, Mei Wang, Lei Zhao, Nuerguli Youliwasi, Chenguang Liu
      N and Co-doped carbon particles (NCCNPs) were prepared by directly carbonizing ZIF-67 at different temperature. The obtained NCCNPs were modified on glassy carbon electrodes (GCE) for electrochemical detection of dopamine (DA) and uric acid (UA). NCCNPs synthesized at 800 °C modified electrode exhibited the highest sensitivity and lowest detection limit toward DA and UA. The effect of the form and content of N, Co species on the detection performance were deduced. It was found that the excellent electrochemical sensing performance of the NCCNPs800 modified electrode is related with large amount of Co with high crystallinity, the small amount of doped N with high electron acceptance ability.
      Graphical abstract image

      PubDate: 2017-12-12T08:22:26Z
      DOI: 10.1016/j.micromeso.2017.11.052
      Issue No: Vol. 263 (2017)
       
  • Nanostructured silver silica materials as potential propolis carriers
    • Authors: Margarita Popova; Hristina Lazarova; Boryana Trusheva; Milena Popova; Vassya Bankova; Judith Mihály; Hristo Najdenski; Iva Tsvetkova; Ágnes Szegedi
      Pages: 28 - 33
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Margarita Popova, Hristina Lazarova, Boryana Trusheva, Milena Popova, Vassya Bankova, Judith Mihály, Hristo Najdenski, Iva Tsvetkova, Ágnes Szegedi
      It is reported for first time, that silver modified nanoporous MCM-41 or SBA-15 silicas are promising carriers for the preparation of poplar propolis loaded dermal formulations. MCM-41 or SBA-15 were successfully modified with 5–15 nm sized silver nanoparticles by direct or post synthesis methods. The formed silver nanoparticles are stabilized in the channels or on the outer surface of nanoporous supports. Poplar propolis molecules were loaded into the mesoporous channels by impregnation. The parent and poplar propolis loaded formulations were characterized by powder XRD, N2 physisorption, thermal analysis and ATR FT-IR spectroscopy. In vitro release of poplar propolis and silver was studied in phosphate buffer at pH = 5.5 which is typical for dermal formulations. Adsorption of poplar propolis on nanoporous silica particles significantly improves its water solubility. Moreover propolis loaded silver-silica systems show significantly better antibacterial and antifungal activities than poplar propolis and silver-modified carriers themselves.
      Graphical abstract image

      PubDate: 2017-12-12T08:22:26Z
      DOI: 10.1016/j.micromeso.2017.11.043
      Issue No: Vol. 263 (2017)
       
  • Facile and controllable preparation of different SBA-15 platelets and
           their regulated drug release behaviours
    • Authors: Haibo Long; Wei Wang; Weiling Yang; Yiran Wang; Hongqiang Ru
      Pages: 34 - 41
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Haibo Long, Wei Wang, Weiling Yang, Yiran Wang, Hongqiang Ru
      Based on the simplest TEOS/P123/HCl(aq.) templating system, it is demonstrated in this work that different SBA-15 platelets can be controllably prepared via the partitioned cooperative self-assembly (PCSA) process without using any additives or complicated procedures. Experimental results show that the reduced amounts of TEOS added in the 2nd additions in the PCSA process play a determining role in transforming the SBA-15 platelet morphologies from the plane ones to a unique kind of UFO-shaped ones. The obtained SBA-15 platelets, plane or UFO-shaped ones, are composed of plugged mesochannels aligned in a 2D hexagonal symmetry, with neighboring channels connected by large tunnel holes (intrawall pores). Different platelet morphologies and their evolution were found to be dependent on partitioning conditions (2nd TEOS addition and interval time). A competitive process involving the aggregation of SBA-15 primary particles dictates the formation of SBA-15 particles with different morphologies, meanwhile the UFO-shaped SBA-15 platelets (U-SBA-15P) can be deemed as intermediate ones between rod-like particles and plane platelets. Moreover, upon the release of indometacin (IMC) in simulating intestinal fluid, UFO-shaped SBA-15 platelets show faster drug release performance compared with their plane counterparts or conventional SBA-15 fibers. The larger the protruded areas in UFO-shaped platelets, the higher the release rate will be. This work, as we believe, presents a new strategy to regulate drug releasing performance by simply tuning particle morphologies of SBA-15 platelets and can allow rational design of IMC/meso-silica formulations.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.11.035
      Issue No: Vol. 263 (2017)
       
  • Hierarchical porous nitrogen-doped carbon beads derived from biosourced
           chitosan polymer
    • Authors: Camélia Matei Ghimbeu; Valeriy A. Luchnikov
      Pages: 42 - 52
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Camélia Matei Ghimbeu, Valeriy A. Luchnikov
      Carbon microbeads with diameters of a few hundreds of microns are produced by dropping chitosan acetate (CA) solution in liquid nitrogen, freeze drying and thermal treatment in inert atmosphere at 700 °C. The structure of the beads is characterized by hierarchical porosity at the three length scales: (i) macropores originating from the phase separation during the water ice crystal grow inside the droplets, immersed in liquid nitrogen, (ii) mesoporores arising in course of the beads thermal treatment, leading to the removal of the porogen molecules (Pluronic F127) added to the CA solution and (iii) micropores induced by the carbonization of chitosan resin. The carbon beads have a rigid skin which present wrinkles with well-defined structure. The carbon bead pore size and volume could be tuned with glyoxal and glyoxylic acid which are able to cross-link in a different manner with chitosan as showed by 13C NMR. The beads are produced by a green process employing entirely biosourced and renewable materials that make them attractive for the large scale applications requiring nanoporous carbons.
      Graphical abstract image

      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.001
      Issue No: Vol. 263 (2017)
       
  • Effects of chemical and physical heterogeneity on confined phase behavior
           in nanopores
    • Authors: Evan Lowry; Mohammad Piri
      Pages: 53 - 61
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Evan Lowry, Mohammad Piri
      It is well known that fluids confined within nanoporous media often experience drastic and unexpected changes in thermodynamic properties. Recent research has focused on uncovering the mechanisms as well as pore size dependent effects. Unfortunately, very little insight is available for how pore wall chemistry and heterogeneity affect the fluid phase behavior. In this study, grand canonical Monte Carlo (GCMC) simulations were employed to investigate the effects of three different pore types on the fluid phase behavior and thermodynamic properties of ethane. Pores were created in sizes ranging from 3 nm to 6 nm and composed of either carbon or amorphous silica. Thermodynamic properties were calculated using particle number fluctuations, energy, and the grand canonical partition function. Results showed that ethane experienced a notable reduction in entropy due to layering effects within the carbon pores composed of a face centered cubic lattice structure. This layering effect was not observed in the amorphous silica pores. The combination of atomic disorder, chemical dissimilarity and lessened pore-fluid potential resulted in less reduction of the critical temperature within confinement. The results concluded that the pore structure leads to distinct shifts in the confined critical temperature depending upon the level of pore material disorder and surface chemistry. Both higher levels of atomic disorder and increasing chemical differences between the surface and adsorbate resulted in less critical point depression as compared to the ordered carbon pores which are commonly used in the literature. This paper showed that the effects of surface chemistry and atomic disorder are non-negligible factors when considering adsorption at the nanoscale.
      Graphical abstract image

      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.11.045
      Issue No: Vol. 263 (2017)
       
  • Fabrication of high-performance antifogging and antireflective coatings
           using faujasitic nanozeolites
    • Authors: Li Cao; Hong Hao; Prabir K. Dutta
      Pages: 62 - 70
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Li Cao, Hong Hao, Prabir K. Dutta
      Colloidal solution of zeolite Y and silica nanoparticles were deposited on glass slides by a dipping method and dried under mild conditions to prepare thin transparent coatings. The thickness of the coatings was controlled by the number of dipping cycles. The zeolite coatings showed antireflection properties with a maximum transmittance of 98% and the average transmittance of 97% in the wavelength range of 400–700 nm. The zeolite coatings also exhibited superhydrophilicity with a water contact angle of ∼4.5°, and exhibited good antifogging properties. Over a six-month period under ambient conditions, there were no significant changes in the antifogging property. The zeolite coatings fared better as antireflection/antifogging coatings prepared with the same number of dipping cycles, as compared to the silica. For films with comparable thickness, the zeolite films also exhibited superior properties and the porous structure of the zeolite, its hydrophilicity and the void structure created by packing of the nanoparticles were considered relevant for rapid dispersion of the water into the film.
      Graphical abstract image

      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.002
      Issue No: Vol. 263 (2017)
       
  • Ultrahigh adsorption capacities of carbon tetrachloride on MIL-101 and
           MIL-101/graphene oxide composites
    • Authors: Yue Zheng; Fuchen Chu; Bing Zhang; Jun Yan; Yunlin Chen
      Pages: 71 - 76
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Yue Zheng, Fuchen Chu, Bing Zhang, Jun Yan, Yunlin Chen
      Hybrid composites of MIL-101(Cr) and graphene oxide (GrO) were prepared using a hydrothermal synthesis method. The synthesized materials were characterized using scanning electron microscopy, X-ray diffraction, FT-IR spectroscopy, thermal analysis and nitrogen adsorption. Results indicated that the specific area and pore volume of MIL-101/GrO-0.25 was much higher than pure MIL-101, and the adsorption capacities of carbon tetrachloride on the MIL-101 (Cr)/GrO was also higher than MIL-101. Moreover, the Langmuir-Freundlich (L-F) equation gave a well fit to the adsorption isotherm data of carbon tetrachloride. The result showed that the adsorption capacity of carbon tetrachloride on the MIL-101 at 303 K was 2044.4 mg/g, and the adsorbing amount on the MIL-101/GrO-0.25 was up to 2368.1 mg/g, which increased by 16% in comparison with the original MIL-101. The synthesized MIL-101/GrO composites exhibited a higher carbon tetrachloride uptake capacity than normal MIL-101 owing to the increasing of specific area, dispersion forces and defects on the crystal surface. Furthermore, the carbon tetrachloride uptakes of MIL-101 and MIL-101/GrO composites were well above those of conventional adsorbents, such as activated carbons and zeolites. It was demonstrated that the MIL-101 and MIL-101/GrO composite are promising adsorbents for application in the field of chlorinated volatile organic compounds (Cl-VOCs) adsorption.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.007
      Issue No: Vol. 263 (2017)
       
  • Tunable interlayer hydrophobicity in a nanostructured high charge
           organo-mica
    • Authors: Carmen Pesquera; Fernando Aguado; Fernando González; Carmen Blanco; Lidia Rodríguez; Ana C. Perdigón
      Pages: 77 - 85
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Carmen Pesquera, Fernando Aguado, Fernando González, Carmen Blanco, Lidia Rodríguez, Ana C. Perdigón
      A tunable hydrophobicity, from a fully hydrophobic medium to an amphiphilic quasi-solution, has been obtained in the interlayer space of a synthetic high charged mica by ion exchange reaction with amine cations. The structural and intercalation properties of the hybrids after the exchange with the n-alkylammonium cations: [RNH3]+, [RNH(CH3)2]+ and [RN(CH3]3 + with C16 alkyl chain length have been determined by termogravimetric/differential scanning calorimetry analysis (TGA-DSC) and mass spectrometry (MS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Transmission electron microscopy (TEM) has been used as a complementary technique to provide new insights into the morphology of the exchanged products. Coverage and cation distribution have been correlated with layer charge and steric effects. Thus, a full organo-clay is obtained when the primary amine cations are adsorbed between the layers. However, a homogenous single phase of mixed organic/inorganic cations is formed in the same interlayer with the tertiary amine cations. Mixed ion clays combining both exchangeable inorganic and adsorbent organic ions in their interlayer space can be potential materials to be used as adsorbents for water decontamination, independently of the hydrophilic/hydrophobic nature of the pollutants. For the quaternary amine cations steric effects preclude the coexistence of both organic and inorganic species in the same interlayer of the clay so phase segregation together with a heterogeneous phase of organic and inorganic galleries in the same particle can be observed.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.006
      Issue No: Vol. 263 (2017)
       
  • Crystal-fluid interactions in laumontite
    • Authors: Davide Comboni; G. Diego Gatta; Paolo Lotti; Marco Merlini; Michael Hanfland
      Pages: 86 - 95
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Davide Comboni, G. Diego Gatta, Paolo Lotti, Marco Merlini, Michael Hanfland
      The elastic behavior and the structural evolution at high pressure of a natural Ca-laumontite and Ca-leonhardite, the partially dehydrated form of Ca-laumontite, have been investigated by in situ single-crystal synchrotron X-ray diffraction up to 2.7 GPa and 7.5 GPa, respectively, using a diamond anvil cell. Despite no phase transitions have been observed within the P-range investigated, an anomalous stiffening of the structure along the b crystallographic axis occurs at about 2.1 GPa in Ca-laumontite and 2.4 GPa in Ca-leonhardite. The isothermal bulk elastic parameters of Ca-laumontite, refined by a second order Birch–Murnaghan equation of state (BM-EoS) fit, are: V 0  = 1393.9(6) Å3 and K V0 = 54.8(10) GPa; whereas the isothermal bulk elastic parameters of Ca-leonhardite, refined by a third order BM-EoS fit, are: V 0  = 1348(1) Å3, K V0 = 36(1) GPa and K V ’ = 2.4(3). The hydration process, at ambient P-T conditions, of Ca-leonhardite has also been studied by means of in-situ single crystal X-ray diffraction in several H2O-based mixtures. The results show that the hydration process is influenced by the fraction of H2O in the aqueous mixtures in which leonhardite is immersed, and an almost linear correlation between the occupancy of the crystallographic W1 site and the unit-cell volume has been found. The structure deformation mechanisms that govern the compression of Ca-laumontite and Ca-leonhardite at the atomic scale, as well as those related to the hydration process of Ca-leonhardite, are described.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.003
      Issue No: Vol. 263 (2017)
       
  • Novel SO3H functionalized magnetic nanoporous silica/polymer nanocomposite
           as a carrier in a dual-drug delivery system for anticancer therapy
    • Authors: Margarita Popova; Ivalina Trendafilova; Ágnes Szegedi; Denitsa Momekova; Judith Mihály; Georgi Momekov; László F. Kiss; Károly Lázár; Neli Koseva
      Pages: 96 - 105
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Margarita Popova, Ivalina Trendafilova, Ágnes Szegedi, Denitsa Momekova, Judith Mihály, Georgi Momekov, László F. Kiss, Károly Lázár, Neli Koseva
      Magnetic nanoporous silica particles (MNS) with spherical morphology and 100 nm particle with advanced characteristics suitable for nanomedicine purposes were synthesized. The obtained nanoparticles were modified with SO3H groups in a two-step post synthesis procedure. An anticancer drug, mitoxantrone (MTX), and an anti-inflammatory drug, prednisolone (PRD), were loaded on the silica support. The mitoxantrone loaded MNS-SO3H nanoparticles were coated by chitosan and then prednisolone was infused in the chitosan layer. A second layer of alginate was then applied around the prednisolone and mitoxantrone containing formulation. All materials were characterized by XRD, N2 physisorption, Mössbauer spectroscopy, magnetization measurements and transmission electron microscopy in order to demonstrate that by the applied preparation method around 11 nm sized maghemite crystals embedded in spherical mesoporous silica nanoparticles were obtained with high pore volume and surface area. Thermal gravimetric analysis, ATR FT-IR spectroscopy and in vitro release experiments proved that MTX and PRD were successfully loaded on the silica matrix. Alginate coating further improved the release properties by preventing the burst release of MTX and PRD. The cytotoxicity properties of the drugs loaded formulations and their ability to retain the intrinsic pharmacological properties of the encapsulated drugs were investigated on a panel of human tumor cell lines.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.005
      Issue No: Vol. 263 (2017)
       
  • Zeolite/silica aerogel composite monoliths and microspheres
    • Authors: Kseniya A. Sashkina; Pavel A. Gurikov; Artem B. Ayupov; Irina Smirnova; Ekaterina V. Parkhomchuk
      Pages: 106 - 112
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Kseniya A. Sashkina, Pavel A. Gurikov, Artem B. Ayupov, Irina Smirnova, Ekaterina V. Parkhomchuk
      A series of silica aerogels and composite materials based on Fe-silicalite-1 nanocrystals embedded into silica aerogel matrix in the form of monoliths and microspheres have been synthesized by drying with supercritical CO2. Using equivolume water/ethanol mixture as a medium for the aging of monoliths enabled to produce monoliths of silica aerogel and composite without cracks. The synthesis of the composite and silica aerogel microspheres by the emulsion/gelation technique has been designed. The different effects of the stirring rate during the emulsification on the particle size and texture of composites and silica aerogels has been observed. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy and nitrogen adsorption measurements.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.010
      Issue No: Vol. 263 (2017)
       
  • SERS self-monitoring of Ag-catalyzed reaction by magnetically separable
           mesoporous Fe3O4@Ag@mSiO2
    • Authors: Yin Xu; Xuefeng Yan; Wenzhang Fang; Stéphane Daniele; Jinlong Zhang; Lingzhi Wang
      Pages: 113 - 119
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Yin Xu, Xuefeng Yan, Wenzhang Fang, Stéphane Daniele, Jinlong Zhang, Lingzhi Wang
      Well-dispersed Fe3O4@Ag@mSiO2 nanoparticle was fabricated by encapsulating Ag into yolk-shell structured Fe3O4@mSiO2 composed of superparamagnetic Fe3O4 core and mesoporous SiO2 shell with bi-solvent nanocasting technique using AgNO3 as the precursor. Ag can dwell in both the cavity between Fe3O4 and mesoporous SiO2 as an asymmetric shell and the mesoporous channel, or exclusively fill the cavity through increasing the reduction temperature of AgNO3 from 350 to 550 °C. The asymmetric Ag shell proves to be high SERS-sensitive for the detection of methyl blue dispersed in ethanol solution as assisted by magnetically separation, with an enhanced factor of 5.02 × 104. The SERS self-monitoring NaBH4 reduction of p-nitrothiophenol catalyzed by Ag nanoclusters in the pore channel was further in situ and real-time achieved with an excellent recyclability.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.013
      Issue No: Vol. 263 (2017)
       
  • An enhanced adsorption of organic dyes onto NH2 functionalization
           titanium-based metal-organic frameworks and the mechanism investigation
    • Authors: Yu-Han Fan; Shou-Wen Zhang; Shi-Bin Qin; Xiao-Shui Li; Shi-Hua Qi
      Pages: 120 - 127
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Yu-Han Fan, Shou-Wen Zhang, Shi-Bin Qin, Xiao-Shui Li, Shi-Hua Qi
      In this paper, the enhanced adsorption properties and mechanism of NH2 functionalization titanium-based metal-organic frameworks (NH2-MIL-125(Ti)) towards various organic dyes was investigated. First, MIL-125(Ti) and NH2-MIL-125(Ti) were successfully synthesized and characterized. The as-prepared Ti-MOFs can be facilely magnetized by adsorbing Fe3O4 nanoparticles on their surfaces via a Lewis acid-base interaction. Then, three types of dye (cationic dye, anionic dye and vat dye) adsorption measurements show that the electrostatic interaction, π-π stacking interaction and pore filling all play important roles in the adsorption process of both Ti-MOFs in aqueous solutions. Particularly, the amino group in NH2-MIL-125(Ti) can provide extra hydrogen bonding interaction towards target substances, which results in a stronger interaction force and a higher adsorption capacity than that of MIL-125(Ti). The adsorption kinetics and isotherm suggested the adsorption process of both Ti-MOFs towards methylene blue (MB) were better fitted to a pseudo-second-order kinetic and Freundlich isotherm model. The adsorption thermodynamic experiments demonstrated that adsorption of MB on both Ti-MOFs was spontaneous. However, their values of enthalpy and entropy were opposite, indicating that their adsorption processes were controlled by enthalpy and entropy effect, respectively.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.016
      Issue No: Vol. 263 (2017)
       
  • Porous CaCO3 carriers loaded with scintillation nanoparticles and
           photosensitizer molecules for photodynamic activation
    • Authors: S.L. Yefimova; T.N. Tkacheva; P.O. Maksimchuk; I.I. Bespalova; K.O. Hubenko; I.A. Borovoy; G.V. Grygorova; V.P. Semynozhenko; R.S. Grynyov; A.V. Sorokin; Yu.V. Malyukin
      Pages: 128 - 134
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): S.L. Yefimova, T.N. Tkacheva, P.O. Maksimchuk, I.I. Bespalova, K.O. Hubenko, I.A. Borovoy, G.V. Grygorova, V.P. Semynozhenko, R.S. Grynyov, A.V. Sorokin, Yu.V. Malyukin
      We report the creation of a novel composition on the base of porous CaCO3 microspheres loaded with both scintillating gadolinium orthovanadate nanoparticles doped with europium ions GdVO4:Eu3+ (VNPs) and Methylene Blue (MB) photosensitizer molecules. It has been shown that upon both UV- and X-ray excitations of VNPs, an excitation energy transfer from VNPs to MB dye molecules takes place that is revealed in the donor VNPs luminescence intensity and lifetime decrease, as well as MB FRET-induced luminescence appearance. The rise time of the acceptor MB luminescence, which follows the donor decay time has been observed that allows distinguishing of nanosecond acceptor emission due to direct acceptor excitation from the much longer-lived sub-millisecond FRET-induced acceptor one. Using the rise time of acceptor luminescence, FRET efficiency (E = 59%) rate constant ( k t = 2.28 · 10 3 s − 1 ) and physical separation of the donor to acceptor within CaCO3 microparticles ( r d a = 2.45 n m ) at the optimal acceptor concentration have been calculated. The efficiency of created CaCO3@VNPs@MB composition in free radical generation has been analyzed.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.020
      Issue No: Vol. 263 (2017)
       
  • Hierarchical porous MCM-68 zeolites: Synthesis, characterization and
           catalytic performance in m-xylene isomerization
    • Authors: He Hao; Yue Chang; Wenjun Yu; Lan-Lan Lou; Shuangxi Liu
      Pages: 135 - 141
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): He Hao, Yue Chang, Wenjun Yu, Lan-Lan Lou, Shuangxi Liu
      Novel hierarchical MCM-68 zeolite materials were successfully prepared by two simple, effective and environmentally friendly methods: H2O2 microexplosion under microwave and NH3(aq) treatment. The characterization of the materials with powder XRD, SEM, TEM, N2-sorption, and NH3-TPD proved that abundant mesopores across zeolite crystals were created while the microporous MSE framework was well preserved. The mesopore volume of hierarchical MCM-68 zeolites is up to 0.19 cm3 g−1. The crystallinities of hierarchical ones and microporous MCM-68 are nearly the same according to the XRD result. The acidities of hierarchical MCM-68 are generally lower than their raw materials. Gas-phase isomerization reaction of m-xylene was carried out over these hierarchical MCM-68 zeolites as well as HMCM-68 zeolite under different conditions to characterize the catalytic property of newly prepared hierarchical zeolites. It was found that the m-xylene conversion and disproportionation/isomerization rate ratio were closely related to the created mesopores in hierarchical MCM-68 zeolites under high reaction temperature and low weight hourly space velocity (WHSV). Moreover, these hierarchical MCM-68 zeolites exhibited improved resistance to coke formation compared with HMCM-68.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.009
      Issue No: Vol. 263 (2017)
       
  • Selectivity and stability of zeolites [Ca]A and [Ag]A towards ethylene
           adsorption and desorption from complex gas mixtures
    • Authors: Ilona van Zandvoort; Gerard P.M. van Klink; Ed de Jong; Jan C. van der Waal
      Pages: 142 - 149
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Ilona van Zandvoort, Gerard P.M. van Klink, Ed de Jong, Jan C. van der Waal
      Producer gas originating from the gasification of biomass has a complex composition, especially compared to its coal or gas based counterparts. Separation of these mixtures is a crucial step in a commercial process, which can effectively be achieved by selective adsorption. In this paper the adsorptive separation of ethylene from a typical complex gas mixture containing N2, H2, CH4, C2H4, C2H6, CO and CO2 on zeolites [Ca]A and [Ag]A using a set-up for high throughput screening is described. It was shown that [Ca]A has a high ethylene adsorption capacity, whereas ethane and CO2 are co-adsorbed. Desorption of ethylene from [Ca]A is slow, but the adsorption capacity could be restored fully. In addition, the material is stable over 15 subsequent adsorption/desorption cycles without loss in performance. On the other hand, [Ag]A has a high adsorption selectivity for ethylene. However, its stability and ethylene recovery from the material is low, since only 80% of the original ethylene adsorption capacity was recovered after the first cycle. The adsorption capacity and selectivity decreases even further in subsequent cycles. This decrease in adsorption capacity and selectivity is caused by the reduction of the Ag+ ion to metallic silver and agglomeration to larger particles due to the presence of reducing gases, e.g. ethylene, CO and H2, in the gas stream.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.004
      Issue No: Vol. 263 (2017)
       
  • Development of micro-mesoporous materials with lamellar structure as the
           support of NiW catalysts
    • Authors: Evgeny R. Naranov; Alexey A. Sadovnikov; Anton L. Maximov; Eduard A. Karakhanov
      Pages: 150 - 157
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Evgeny R. Naranov, Alexey A. Sadovnikov, Anton L. Maximov, Eduard A. Karakhanov
      An original approach for preparing hybrid support ZSM-5/MCM-41 is presented. Three types of ZSM-5/MCM-41(X) (X – thermostating time; 0, 6, 16 h) materials were synthesized with the different thermostating time of the mesoporous structure. The adopted preparation strategy was based on the effective synergy of sulfided particles and porous structure of the support. The NiW/ZSM-5/MCM-41(6; 16) catalysts demonstrated high activity in naphthalene hydrogenation under mild conditions, the ring-opening products selectivity was 32–36%. The deep aromatics saturation in light cycle oil (LCO) was observed over NiW/ZSM-5/MCM-41(16) catalyst at the following conditions: 5.0 MPa pressure, 2.0 h−1 LHSV, 300 l/l H2 -to-LCO volume ratio, and temperature of 360–380 °C.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.021
      Issue No: Vol. 263 (2017)
       
  • Controllable preparation of polymer brushes from mesoporous silica SBA-15
           via surface-initiated ARGET ATRP
    • Authors: Mingsen Chen; Lanmei Qin; Yuanli Liu; Faai Zhang
      Pages: 158 - 164
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Mingsen Chen, Lanmei Qin, Yuanli Liu, Faai Zhang
      Surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) was employed for controlled grafting of poly(glycidyl methacrylate) (PGMA) and poly(glycidyl methacrylate)-b-poly(methyl methacrylate) (PGMA-PMMA) brushes from mesoporous silica SBA-15. Initiator 2-bromoisobutyryl bromide (BiBB) was immobilized onto the inner surface of SBA-15 by reaction with free silanol groups. The polymerizations were conducted in the mixed solvents cyclohexanone /N, N-dimethylformamide. The strategy of utilizing mixed solvents gave rise to a suitable polymerization rate and resulted in a good control of the PGMA growth within the SBA-15 framework and could obtain polymer chains with well-preserved chain end functionality. Molecular weight of grafted polymer, structure, morphology, and composition of the functionalized SBA-15 were characterized by using gel permeation chromatography (GPC), X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption/desorption measurements, fourier transform infrared spectroscope (FT-IR), and thermogravimetry analysis (TGA), respectively. The thickness, polymer grafting density and molecular weight of the grafted polymer can be controlled by adjusting the polymerization time. The deactivator cannot efficient diffuse to convert the propagating chains to the dormant species when the pores are nearly completely filled with the polymer, therefore, increasing grafting density resulted in higher molecular weight and polydispersity index (PDI) values for the grafted polymer chains. This work provides a facile route for preparation of well-defined mesoporous silica/polymer hybrids.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.019
      Issue No: Vol. 263 (2017)
       
  • Thermodynamics and kinetics of CH4/CO2 binary mixture separation by
           metal-organic frameworks from isotope exchange and adsorption
           break-through
    • Authors: Renju Zacharia; Luis Fernando Gomez; Richard Chahine; Daniel Cossement; Pierre Benard
      Pages: 165 - 172
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Renju Zacharia, Luis Fernando Gomez, Richard Chahine, Daniel Cossement, Pierre Benard
      We combine the isotope exchange technique (IET) with the conventional Sieverts method, microcalorimetry, breakthrough experiments and multi-scale modelling to comprehensively and quantitatively investigate the thermodynamics and kinetics of equimolar CH4/CO2 mixture separation in metal organic frameworks. The prototypical MOF-5 is selected for this work as it allows benchmarking our binary mixture results with the pure gas data widely reported in the literature. For the first time, an experimental binary gas adsorption isotherm of CH4/CO2 on MOF-5 is reported and compared with the respective pure gas isotherms. The equilibrium thermodynamic selectivity from the IET experiments for the equimolar CH4/CO2 separation is found to be 8.3 while a much lower value of 2.83 is obtained from the ideal adsorption solution theory (IAST). The large standard deviation of the model selectivities and the significant deviation of averaged model selectivity from the experimental one clearly reinforces the necessity to determine the selectivity reliably using experiments. The kinetic selectivity for the binary mixture separation determined by combining the results of IET with the linear driving force (LDF) model is 0.73. The co-adsorption heats and excess uptake of both gases in mixtures are lower than those of pure gases; we observe that the intrinsically weaker sorption of CH4 on MOF-5 is further weakened by the presence of strongly interacting CO2. Thermodynamic and kinetic selectivities and the co-adsorption heats quantitatively suggests that CH4/CO2 separation is driven by the equilibrium thermodynamic factors with no significant contribution from kinetic factors.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.011
      Issue No: Vol. 263 (2017)
       
  • Supported choline hydroxide (ionic liquid) on mesoporous silica as
           heterogeneous catalyst for Knoevenagel condensation reactions
    • Authors: Isabel del Hierro; Yolanda Pérez; Mariano Fajardo
      Pages: 173 - 180
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Isabel del Hierro, Yolanda Pérez, Mariano Fajardo
      In this work hybrid mesoporous SBA-15 and mesoporous silica microspheres functionalized with choline hydroxide ionic liquid have been prepared. A two-step process inspired by the industrial production of choline hydroxide has been developed to synthesize the hybrid SBA-15 material with choline hydroxide ionic liquid (Chol-SBA-15) and the hybrid SBA-15 material with choline hydroxide ionic liquid and hexamethyldisilizane as capping agent (Chol-HMDS-SBA-15). For the preparation of hybrid mesoporous silica microspheres (Chol-MSMs), a co-condensation method has been employed with an ionic liquid prepared by reaction of 3-(glycidyloxypropyl)trimethoxysilane and trimethylamine in aqueous media. The synthesized materials have been fully characterized by elemental analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), N2 adsorption-desorption, transmission electron microscopy (TEM) and 13C CP/MAS NMR spectroscopy. These materials have been tested successfully as catalysts in Knoevenagel condensation of benzaldehyde with RCH2C≡N (R = CN (malononitrile), CO2Et (ethyl cyanoacetate)). The catalyst Chol-MSMs showed high catalytic activity, 99% of conversion and 99% of selectivity towards ethyl 2-cyano-3-phenylacrylate in 2 h of reaction and using ethanol as solvent. In addition, their reusability without loss of activity has been demonstrated.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.024
      Issue No: Vol. 263 (2017)
       
  • The impact of thermal activation conditions on physicochemical properties
           of nanosheet-derived Mg-Al mixed oxides
    • Authors: Isao Ogino; Rei Tanaka; Shuichiroh Kudo; Shin R. Mukai
      Pages: 181 - 189
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Isao Ogino, Rei Tanaka, Shuichiroh Kudo, Shin R. Mukai
      Mg-Al mixed oxides with highly accessible basic sites were synthesized from Mg-Al layered double hydroxides bearing interlayer isethionates (Ise). Anion-exchange of interlayer carbonates in synthetic hydrotalcites with Ise induces stacking disorders in layered structure, and subsequent delamination in water followed by drying causes further disordering as characterized by X-ray diffraction technique. However, thermal activation of these materials in air formed Mg-Al mixed oxides with low surface area and low CO2 adsorption capacity. In contrast, thermal activation in N2 or N2 followed by air formed materials exhibiting marked increases in CO2 adsorption capacity up to ∼800% relative to those obtained by thermal activation in air. Thermogravimetric and elemental analyses and IR spectroscopy characterization indicate that thermal activation in N2 enables removal of sulfur species formed from Ise at ∼400 °C, and limits the formation of sulfate species that bridge nanosheets and cause irreversible stacking of them. The proper thermal activation procedure in addition to disordered structure of aggregates of Mg-Al double hydroxide nanosheets enabled the formation of Mg-Al mixed oxides with higher surface area and larger micropore volume than those obtained from the initial hydrotalcites. These results highlight the critical importance of thermal activation steps for such materials, and demonstrate a prospective route to synthesize new porous materials based on Mg-Al mixed oxides.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.014
      Issue No: Vol. 263 (2017)
       
  • Atom economical benzylation of phenol with benzyl alcohol using 20 %
           (w/w)Cs2.5H0.5PW12O40 supported on mesocellular foam silica (MCF) and its
           kinetics
    • Authors: Kalpesh H. Bhadra; Ganapati D. Yadav
      Pages: 190 - 200
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Kalpesh H. Bhadra, Ganapati D. Yadav
      Traditionally benzylation of phenol is carried out with benzyl chloride which is corrosive and difficult to handle, and the resultant reaction is not atom economical. Benzyl alcohol is an alternative to benzyl chloride which is safe and easy to handle. Benzyl phenols are industrially important products particularly in plastic, rubber and petroleum industries. In present study, cesium salt of dodecatungstophosphoric acid (Cs2.5H0.5PW12O40, Cs-DTP) supported on mesocellular foam (MCF) silica was used as catalyst among others. The activity of prepared catalyst, 20% (w/w) Cs-DTP/MCF was compared with Amberlyst-15, montmorillonite clay K10, S-ZrO2 and unsupported Cs-DTP catalyst. The supported catalyst showed better performance because of even distribution of acidic sites on MCF. The effect of reaction parameters were studied in detail and it was found that reaction follows second order kinetics. The activation energy was found to be 15.94 kcal/mol. The catalyst was found reusable.
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      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.017
      Issue No: Vol. 263 (2017)
       
  • Tailoring the hierarchical architecture of beta zeolites using base
           leaching and pore-directing agents
    • Authors: Sergio Fernandez; Michele L. Ostraat; John A. Lawrence; Ke Zhang
      Pages: 201 - 209
      Abstract: Publication date: June 2018
      Source:Microporous and Mesoporous Materials, Volume 263
      Author(s): Sergio Fernandez, Michele L. Ostraat, John A. Lawrence, Ke Zhang
      The tailoring of hierarchical structures in beta zeolites of differing Al contents (Si/Al: 14-250) has been systematically investigated through a top-down base leaching process with various cationic tetraalkylammonium (TAA) salts and organic amines as pore-directing agents (PDAs) to examine their effectiveness in protecting beta zeolite framework while directing the formation of mesopores. The structure-property relationship was established between PDA structure and average mesopore sizes in resulting hierarchical zeolites, especially for high Si beta zeolites when the presence of PDA is necessary to avoid framework amorphization during NaOH desilication. All PDAs studied are effective in directing the mesopore formation in alkaline solutions without experiencing significant decrease in microporosity and crystallinity of parent beta zeolites. For high Si beta zeolites, hierarchical structures with non-ionic amines possess larger mesopores (average mesopore sizes, d a : 5-8 nm) than those treated with TAA cationic PDAs (d a : 2-6 nm), which should be due to better accommodation of TAA-type cationic PDAs within the inner channel of beta framework and more favorable interaction and protection of parent framework as compared to organic amines. For similarly structured TAA cations, the resulting mesopore sizes and surface areas are correlated with the molecular weights of different cations, i.e. higher molecular weight cations result in smaller d a and correspondingly larger surface areas. Therefore, it is feasible to tailor the mesopore sizes by a top-down base leaching with an appropriate selection of PDAs for beta zeolites. The successful introduction of mesopores in beta zeolites also led to significantly improved catalytic conversion for the acid-catalyzed alpha-pinene isomerization, as compared to the parent beta catalysts.
      Graphical abstract image

      PubDate: 2017-12-27T06:17:41Z
      DOI: 10.1016/j.micromeso.2017.12.023
      Issue No: Vol. 263 (2017)
       
 
 
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