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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  [3175 journals]
  • Ultrafast synthesis of *BEA zeolite without the aid of aging pretreatment
    • Authors: Jie Zhu; Zhendong Liu; Sohei Sukenaga; Mariko Ando; Hiroyuki Shibata; Tatsuya Okubo; Toru Wakihara
      Pages: 1 - 8
      Abstract: Publication date: 15 September 2018
      Source:Microporous and Mesoporous Materials, Volume 268
      Author(s): Jie Zhu, Zhendong Liu, Sohei Sukenaga, Mariko Ando, Hiroyuki Shibata, Tatsuya Okubo, Toru Wakihara
      The present study focuses on the ultrafast synthesis of *BEA zeolite, which constitutes one of the most industrially important zeolites. A pure *BEA phase was successfully synthesized within 10 min at 210 °C by carefully tuning the composition of the initial reactant mixture. To date, the ultrafast synthesis of several industrially important zeolites is achieved with the aid of aging pretreatment, followed by high temperature hydrothermal treatment. In this study, we first demonstrated the 10-min synthesis of *BEA zeolite employing organic structure-directing agents (OSDAs), without any aging process. The employment of sealed pipe reactor in conjunction with the optimization of chemical composition of starting materials are critical in obtaining pure *BEA phase in a short time. The fast-synthesized *BEA zeolite possesses properties that are similar to those synthesized by conventional hydrothermal synthesis methods in terms of crystallinity and micropore volume. A comprehensive investigation on the effects of various parameters on the seed-assisted crystallization of *BEA zeolite was also studied.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.04.012
      Issue No: Vol. 268 (2018)
       
  • Enhanced lithium ion battery performance of nano/micro-size Si via
           combination of metal-assisted chemical etching method and ball-milling
    • Authors: Xiangyang Zhou; Song Chen; Haochen Zhou; Jingjing Tang; Yongpeng Ren; Tao Bai; Jiaming Zhang; Juan Yang
      Pages: 9 - 15
      Abstract: Publication date: 15 September 2018
      Source:Microporous and Mesoporous Materials, Volume 268
      Author(s): Xiangyang Zhou, Song Chen, Haochen Zhou, Jingjing Tang, Yongpeng Ren, Tao Bai, Jiaming Zhang, Juan Yang
      Up to now, designing special Si with high coulombic efficiency and cycling stability in a bulk electrode remains a significant challenge. In this work, nano/micro-structured Si was successfully synthesized via a simple and scalable process with combination of the modified Metal-assisted chemical etching (MACE) method and ball-milling. The modified MACE method was used to purify micro-silicon (mSi) and produce porous structure. Moreover, we decrease the size of porous Si (pSi) and introduce the oxidation layer (∼3.8 nm) through simple ball-milling to prepare nano/micro-structured Si (M-pSi), which delivers a high initial coulombic efficiency of 85.2%, high capacity and good cycle performance. The initial discharge capacity of M-pSi is 2349 mA h g−1 at a current density of 0.2 C (1 C = 4200 mA g−1) and remains 2231 mA h g−1 after 100 cycles, suggesting an average decrease of 0.05% per cycle. Even at a higher current density of 2 C, it delivers a high discharge capacity of 750 mA h g−1.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.035
      Issue No: Vol. 268 (2018)
       
  • Synthesis and characterization of Mn-Silicalite-1 by the hydrothermal
           conversion of Mn-magadiite under the neutral condition and its catalytic
           performance on selective oxidation of styrene
    • Authors: Jing Zhao; Yifu Zhang; Shaoqing Zhang; Qiushi Wang; Meng Chen; Tao Hu; Changgong Meng
      Pages: 16 - 24
      Abstract: Publication date: 15 September 2018
      Source:Microporous and Mesoporous Materials, Volume 268
      Author(s): Jing Zhao, Yifu Zhang, Shaoqing Zhang, Qiushi Wang, Meng Chen, Tao Hu, Changgong Meng
      The incorporation of manganese into the framework of Silicalite-1 (denoted as Mn-Silicalite-1) was achieved by the hydrothermal conversion manganese ion exchanged magadiite (Mn-magadiite) under the neutral condition. The influences of the synthetic conditions (the reaction time, the reaction temperatures and the precursors) on the synthesis of Mn-Silicalite-1 were studied in detail to reveal the successful synthesis of Mn-Silicalite-1. The introduction of the manganese into the framework of Silicalite-1 was demonstrated by the means of X-ray powder diffraction (XRD), energy-dispersive X-ray spectrometer (EDS), elemental mapping, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–Vis), field emission scanning electron microscopy (FE-SEM), N2 adsorption/desorption isotherms and temperature-programmed reduction (TPR). The BET surface area (SBET) and pore volume (Vp) of Mn-Silicalite-1 measured 323 m2/g and 0.052 cm3/g, respectively. All results confirmed that Mn atoms were successfully doped into the framework of Silicalite-1 and homogeneous solid-solutions of Mn-Silicalite-1 were synthesized. Furthermore, the catalytic properties of the as-synthesized Mn-Silicalite-1 were evaluated by the styrene oxidation reaction. Mn-Silicalite-1 significantly increased the active sites of the catalyst and improved the catalytic efficiency. Low temperature was beneficial to the formation of styrene oxide and high temperature was beneficial to the formation of benzaldehyde.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.04.009
      Issue No: Vol. 268 (2018)
       
  • Zeolite/dye hybrid composites: Organization of photoactive azobenzene
           molecules inside AlPO4-5
    • Authors: Michelangelo Polisi; Rossella Arletti; Sara Morandi; Marco Fabbiani; Gianmario Martra; Simona Quartieri; Linda Pastero; Giovanna Vezzalini
      Pages: 25 - 30
      Abstract: Publication date: 15 September 2018
      Source:Microporous and Mesoporous Materials, Volume 268
      Author(s): Michelangelo Polisi, Rossella Arletti, Sara Morandi, Marco Fabbiani, Gianmario Martra, Simona Quartieri, Linda Pastero, Giovanna Vezzalini
      Organic/inorganic hybrid materials - like zeolites + dyes - are currently used in strategic areas, from sustainable energy technologies to biomedical sciences. In these systems, photoactive molecules are organized in one-dimensional nanostructures inside the zeolite channels. In this paper we present the results of a study aimed to the synthesis and the structural and spectroscopic characterization of azobenzene/AlPO4-5 hybrid composites, performed by a multi-technique approach based on material synthesis, thermal gravimetric analysis, synchrotron X-ray powder diffraction, UV-VIS and IR spectroscopies. The results indicate that azobenzene molecules are hosted in the 12-membered ring channel of AFI framework and the maximum loading is 0.9 molecules per unit cell. The combination of spectroscopic and diffractometric methods point out that, being AlPO4-5 starting material affected by Brönsted acidity, a consistent portion of the azobenzene molecules is protonated and interact with the framework oxygen atoms.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.038
      Issue No: Vol. 268 (2018)
       
  • Interaction between adsorbed molecules and tailor made large chelating
           ligands grafted on SBA-15 studied by means of thermoporometry
    • Authors: Agnieszka Węgrzyn; Marcelina Radko; Dorota Majda; Wojciech Stawiński; Michał Skiba; Dariusz Cież
      Pages: 31 - 38
      Abstract: Publication date: 15 September 2018
      Source:Microporous and Mesoporous Materials, Volume 268
      Author(s): Agnieszka Węgrzyn, Marcelina Radko, Dorota Majda, Wojciech Stawiński, Michał Skiba, Dariusz Cież
      Modified mesoporous silicas were examined as adsorbents for efficient removal of model pollutants from wastewaters. Functionalized SBA-15 materials for capture of cationic pollutants such as metal cations and anionic dyes were obtained using post-synthesis grafting method. Large organic ligands containing acetyloacetone, 2-aminopyridine, 2-aminothiazole and 2-aminobenzothiazole groups were incorporated into the adsorbents' structure. The adsorption capacities reached levels of 38.6, 43.1, 64.3, 68.6 and 88.9 mg g−1 for Cu2+, Rose Bengal, Congo Red, Levafix Amber CA gran and Methyl Orange, respectively. Moreover, the adsorption efficiency depended on a type of the model molecule and a type of the surface chelating group. The pores' size and the pores' volume of the hybrid materials before and after adsorption was determined in hydrated state using thermoporometry. For the first time, by means of this methodology, it was possible to propose a model of interactions between the adsorbed molecules and the grafted organosilanes. Adsorption of organic dyes resulted in most cases in formation of J-aggregates.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.04.010
      Issue No: Vol. 268 (2018)
       
  • Using factorial experimental design to optimize biocatalytic biodiesel
           production from Mucor Miehei Lipase immobilized onto ordered mesoporous
           materials
    • Authors: C. Carteret; J. Jacoby; J.L. Blin
      Pages: 39 - 45
      Abstract: Publication date: 15 September 2018
      Source:Microporous and Mesoporous Materials, Volume 268
      Author(s): C. Carteret, J. Jacoby, J.L. Blin
      A supported biocatalyst was prepared by immobilization of Mucor miehei lipase onto mesoporous silica materials. This material was used for the synthesis of biodiesel through the transesterification of rapeseed oil with methanol. The process of biodiesel production was optimized by application of the factorial design methodology. Methanol to oil molar ratio, water addition, reaction temperature and biocatalyst content were chosen as the variables and the response selected was the yield of esterification. Oil/methanol ratio was found to have the strongest influence on conversion, a low ratio is more favorable. To increase the enzyme activity water has to be added. However excess of water favors the hydrolysis reaction. The temperature has a slight influence. The optimal conditions for the transesterification are: reaction temperature of 24 °C, alcohol/oil molar ratio of 1:1, and water content of 2.5% w/w. Under these reaction conditions the methanol is totally consumed and around a third of the triglycerides are converted. Nearly 100% of the oil was converted to methyl esters with incremental additions of methanol (three increments of methanol at regular time).
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.04.004
      Issue No: Vol. 268 (2018)
       
  • Rapid screening of zeolite acidity by thermal response measurements using
           InfraSORP technology
    • Authors: Anja Werner; Michelle Wöllner; Paul Bludovsky; Matthias Leistner; Carolin Selzer; Stefan Kaskel
      Pages: 46 - 49
      Abstract: Publication date: 15 September 2018
      Source:Microporous and Mesoporous Materials, Volume 268
      Author(s): Anja Werner, Michelle Wöllner, Paul Bludovsky, Matthias Leistner, Carolin Selzer, Stefan Kaskel
      Thermal response measurements using the recently developed InfraSORP technology are nowadays established as a versatile and rapid screening tool for the estimation of physicochemical properties of porous materials, such as adsorption capacity, surface area and porosity. In the present work, InfraSORP experiments are explored for fast screening of zeolite acidity especially for test samples available only in small quantity. Twelve MFI and beta type zeolite samples with varying molar Si/Al ratios were examined using ammonia as test gas (0.5% NH3 in nitrogen). Caused by the exothermic adsorption of ammonia on acidic sites of the zeolite samples, a characteristic temperature response curve (temperature vs. time) is observed. The specific peak area under the curve reflects the total NH3 amount adsorbed. In two consecutive adsorption/desorption runs the contributions of physisorbed and chemisorbed NH3 are distinguished. The difference between the first integral of the thermal response (caused by physisorption and chemisorption of NH3) and a second adsorption cycle (reflecting only weakly adsorbed NH3) correlates directly with the sample acidity determined by conventional temperature-programmed desorption of ammonia (TPD). Calibration of the signal versus established TPD techniques results in excellent correlation and renders the new technique as a promising high-throughput screening tool for zeolite acidity assessment in industrial process and product quality control requiring less than 30 min per sample.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.032
      Issue No: Vol. 268 (2018)
       
  • Adsorptive removal of toluene and carbon tetrachloride from gas phase
           using Zeolitic Imidazolate Framework-8: Effects of synthesis method,
           particle size, and pretreatment of the adsorbent
    • Authors: Saeed Jafari; Farshid Ghorbani-Shahna; Abdulrahman Bahrami; Hossein Kazemian
      Pages: 58 - 68
      Abstract: Publication date: 15 September 2018
      Source:Microporous and Mesoporous Materials, Volume 268
      Author(s): Saeed Jafari, Farshid Ghorbani-Shahna, Abdulrahman Bahrami, Hossein Kazemian
      Dynamic adsorption of toluene and carbon tetrachloride was studied on Zeolitic Imidazolate Framework-8 (ZIF-8). The ZIF-8 was synthesized using environmentally friendly procedures in an aqueous solution at ambient temperature with different concentrations of precursors. ZIF-8 samples were characterized by XRD, FTIR, SEM, DLS, and BET, and the results indicated that both synthesis methods lead to pure ZIF-8 products. The adsorption of toluene and carbon tetrachloride from gas phase was studied in a fixed bed reactor. The effects of different pretreatment conditions, particle size, and surface area of ZIF-8 on the adsorption performance were studied using a breakthrough curve. Experimental results revealed that ZIF-8 adsorption performance was improved as pretreatment temperatures was increased and particle size was reduced. The results of the experimental dynamic adsorption of toluene and carbon tetrachloride on ZIF-8 were fitted into the Thomas and Yan models. It was observed that toluene adsorption breakthrough curves were fitted in both models better than those of carbon tetrachloride curves.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.04.013
      Issue No: Vol. 268 (2018)
       
  • Effect of Si/Al ratio and amount of deposited MFI-type seed crystals on
           the separation performance of silicalite-1 membranes for ethanol/water
           mixtures in the presence of succinic acid
    • Authors: Kyohei Ueno; Hideyuki Negishi; Manabu Miyamoto; Shigeyuki Uemiya; Yasunori Oumi
      Pages: 1 - 8
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Kyohei Ueno, Hideyuki Negishi, Manabu Miyamoto, Shigeyuki Uemiya, Yasunori Oumi
      Silicalite-1 zeolite membranes were prepared on porous tubular α-Al2O3 supports by a secondary growth method. The influences of the Si/Al ratio and the amount of deposited MFI (silicalite-1 and ZSM-5) seed crystals on membrane pervaporation (PV) performance for the separation of ethanol/water (binary) and ethanol/water/succinic acid (ternary) mixtures were investigated. The prepared membranes were characterized by X-ray diffraction and scanning electron microscopy, and the Si and Al distributions in the membrane layers were determined by energy-dispersive X-ray line scanning. Each silicalite-1 membrane was composed of two layers: an MFI-seed-crystal layer that grew on the support surface, and another gel-derived silicalite-1 top layer that formed on the seed crystal layer. The texture of the MFI seed layer (i.e., the deposited amount and the Si/Al ratio) was found to play an important role in the separation process. When silicalite-1 seed crystals were used, the ethanol separation factor was high in the binary ethanol/water system, but lower in the presence of succinic acid. However, when ZSM-5 seeds were used, the ethanol separation factor in the ternary system improved. These results suggest that silicalite-1 membranes prepared using ZSM-5 seed crystals are effective for the recovery of ethanol in the presence of organic acids.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.005
      Issue No: Vol. 267 (2018)
       
  • Synthesis and single crystal structures of V(OH)ndc·H2O, V(OH)ndc,
           and VOndc
    • Authors: Xiqu Wang; Pradeep Samarasekere; Allan J. Jacobson
      Pages: 20 - 23
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Xiqu Wang, Pradeep Samarasekere, Allan J. Jacobson
      The vanadium analog of MIL-69, V(OH)ndc·H2O (ndc = 2,6-naphthalenedicarboxylate) was prepared solvothermally and the structure determined by single crystal X-ray diffraction (Space Group P21/c (#14), a = 6.7936(2) Å, b = 14.6816(4) Å, c = 23.9156(6) Å, β = 91.734(2)°, V = 2394.3(1) Å3). Anhydrous V(OH)ndc was obtained from V(OH)ndc·H2O by heating under nitrogen flow at 378 K in situ the crystal used to determine the structure of the as synthesized hydrated compound. The water molecules are removed on heating in a crystal to crystal transformation. Minor changes in the structure occur with no change in the V3+ oxidation state though the space group symmetry changes from P21/c to C2/c. (Space Group C2/c (#15), a = 24.684(4) Å, b = 7.079(2) Å, c = 6.853(1) Å, β = 104.35(1)°, V = 1160.2(4) Å3). The structure of VOndc (Space Group C2/c (#15), a = 24.628 (2) Å, b = 7.1434(5)Å, c = 6.7428(4) Å, β = 104.637(3)°, V = 1147.8 Å3) obtained by heating V(OH)ndc·H2O in air at 573 K, in contrast shows a change in oxidation state from V3+ to V4+ evidenced by bond valence sum calculations and by the appearance of a characteristic distorted VO6 octahedron and an O⋯V(IV) = O chain.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.020
      Issue No: Vol. 267 (2018)
       
  • N-α-acylation of lysine catalyzed by immobilized aminoacylases from
           Streptomyces ambofaciens in aqueous medium
    • Authors: L. Dettori; F. Vibert; Y. Guiavarc'h; S. Delaunay; C. Humeau; J.L. Blin; I. Chevalot
      Pages: 24 - 34
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): L. Dettori, F. Vibert, Y. Guiavarc'h, S. Delaunay, C. Humeau, J.L. Blin, I. Chevalot
      Aminoacylases (EC 3.5.1.1.4) of Streptomyces ambofaciens ATCC 23877 were immobilized by chemical and physical adsorption onto SBA-15 mesoporous silica materials. The activity of the immobilized aminoacylases was firstly evaluated by considering the hydrolysis reactions of N-α-acetyl-lysine, used as rapid method of screening. After chemical adsorption, a significant loss of activity was observed probably due to a conformational change of the aminoacylases structures upon immobilization. When the immobilization was performed by physisorption a higher amount of enzyme (0.20 against 0.05 mg per mg of support) can be adsorbed onto the mesoporous silica material. The physisorbed biocatalyst also presented a higher hydrolytic activity than the chemisorbed enzyme. Recycling of the supported biocatalysts was performed three times with no loss of the specific activity. Furthermore, a better thermostability was also noted in comparison with free enzyme upon aminoacylases physisorption. Finally, lauroyl-lysine synthesis was catalyzed for the first time by immobilized aminoacylases. The crude extract from S. ambofaciens exhibited the rare ability to catalyze the N-acylation on amino group in the α-position of the lysine whereas the lipase B of Candida antarctica catalyzed the acylation of lysine on its amino group in ε-position. This particular and original regioselectivity was maintained with immobilized enzymes.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.018
      Issue No: Vol. 267 (2018)
       
  • Increasing the stability of the Ge-containing extra-large pore ITQ-33
           zeolite by post-synthetic acid treatments
    • Authors: Aída Rodríguez-Fernández; Francisco J. Llopis; Cristina Martínez; Manuel Moliner; Avelino Corma
      Pages: 35 - 42
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Aída Rodríguez-Fernández, Francisco J. Llopis, Cristina Martínez, Manuel Moliner, Avelino Corma
      Extra-large pore ITQ-33 zeolite (ITT, 18 × 10 × 10-rings) is a very promising catalyst for the catalytic cracking of gasoil but, unfortunately, this material shows a limited hydrothermal stability due to the large germanium content present in the ITQ-33 structure. Taking this into account, the Ge-containing ITQ-33 has been post-synthetically modified using different acid procedures with the aim of studying the effect of these treatments on the overall hydrothermal stability of this extra-large pore zeolite. In this sense, the as-prepared ITQ-33 has been treated with different HCl solutions in ethanol (from 0.1 to 1 M), containing also tetraethylorthosilicate (TEOS) as silicon precursor, at different temperatures (150–175 °C). From the different acid treatments, it is observed that treating ITQ-33 with a TEOS-containing 1 M HCl solution in ethanol at 150 °C for 24 h, allows increasing the Si/Ge ratio from 2 to 3.2, mostly preserving the crystalline structure. If this acid-treatment is repeated three consecutive times, the Si/Ge can be increased up to 7.5, resulting in a highly stable extra-large pore zeolite. This post-synthetically modified ITQ-33 zeolite has been characterized by different techniques, including PXRD, FESEM, N2 and Ar adsorption, ICP and 27Al MAS NMR to unravel its physico-chemical properties. Finally, the catalytic behavior of the treated ITQ-33 zeolite has been tested for the catalytic cracking of gasoil, confirming in this way a remarkably higher hydrothermal stability when compared to the as-prepared Ge-rich ITQ-33, permitting its regeneration for successive catalytic cycles.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.006
      Issue No: Vol. 267 (2018)
       
  • Extended-release of chlorpromazine intercalated into montmorillonite clays
    • Authors: Mohamed Amine Djebbi; Saber Boubakri; Zaineb Bouaziz; Mohamed Slim Elayachi; Philippe Namour; Nicole Jaffrezic-Renault; Abdesslem Ben Haj Amara
      Pages: 43 - 52
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Mohamed Amine Djebbi, Saber Boubakri, Zaineb Bouaziz, Mohamed Slim Elayachi, Philippe Namour, Nicole Jaffrezic-Renault, Abdesslem Ben Haj Amara
      Drugs are rarely defined by a single act in a disease treatment but often elicit a cure with few side effects. In this respect, recent clinical analyses of treatment with antipsychotic drugs such as chlorpromazine (CPZ) show that high dose of CPZ leads to severe extrapyramidal side effects. To address the incidence of these side effects, CPZ was incorporated into montmorillonite (MMt) clay in order to gradually release it over a prolonged period. As a consequence of a lamellar structure and biocompatibility, MMt is mainly used as nanocarrier for the controlled release of several chemical drugs. XRD, FT-IR, DSC-TGA and SEM techniques were used to characterize the structure of the prepared formulation, all confirming the successful intercalation of CPZ into MMt interlayer spaces. The potential application was verified through release of CPZ from CPZ/MMt formulation. The drug release profile indicated that the release of the intercalated CPZ was slower than the release of the CPZ lonely (pure). The presence of the MMt clay in CPZ/MMt capsule beads reduced the release rate and upheld the sustained release of the model drug for a longer period. To elucidate the release mechanism of CPZ from CPZ/MMt formulation, the release data were subjected to release kinetic. Thus, the results suggested the feasibility of the use of MMt clay materials for controlled manner of drugs, and thereby, a sustained release is favorable and side effects reduced.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.017
      Issue No: Vol. 267 (2018)
       
  • CO2 adsorption behavior of amine-functionalized ZIF-8, graphene oxide, and
           ZIF-8/graphene oxide composites under dry and wet conditions
    • Authors: Jeewan Pokhrel; Nidhika Bhoria; Stavroula Anastasiou; Theodoros Tsoufis; Dimitrios Gournis; George Romanos; Georgios N. Karanikolos
      Pages: 53 - 67
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Jeewan Pokhrel, Nidhika Bhoria, Stavroula Anastasiou, Theodoros Tsoufis, Dimitrios Gournis, George Romanos, Georgios N. Karanikolos
      Development and optimization of solid adsorbents is highly sought after toward establishment of energy-efficient and high-throughput CO2 capture processes in industry. Herein, graphene oxide (GO), zeolitic imidazolate framework ZIF-8, and composite ZIF-8/GO adsorbents were developed and further functionalized using various amine functionalities, namely, 3-aminopropyl-triethoxysilane (APTES), polyethyleneimine (PEI), and ethylene diamine (ED). Following structural and morphological evaluation, the resulting adsorbents were tested and compared for CO2 adsorption capacity and kinetics, while their performance under the presence of pre-adsorbed water was evaluated as well. GO functionalization by APTES resulted in a 36% increase in adsorption capacity at 1 bar and 30 °C compared to unmodified GO, and a further 33% increase under the presence of pre-adsorbed water (10% RH) compared to the corresponding APTES-GO capacity under dry conditions. Amine functionalization of ZIF-8 resulted in a capacity increase of up to 43% at 1 bar compared to unmodified ZIF-8, while ZIF-8/GO post-functionalization in water enhanced the capacity of this type of composite adsorbent compared to non-functionalized ZIF-8/GO and the pure ZIF-8 particularly at lower pressures. The reported results can be valuable towards devising optimum paths of functionalization and performance enhancement of these types of adsorbents that can pave the way toward design of highly efficient materials and processes for the current and future CO2 capture needs.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.012
      Issue No: Vol. 267 (2018)
       
  • Polyaniline/FeZSM-5 composites – Synthesis, characterization and their
           high catalytic activity for the oxidative degradation of herbicide
           glyphosate
    • Authors: Maja Milojević-Rakić; Danica Bajuk-Bogdanović; Bojana Nedić Vasiljević; Aleksandra Rakić; Sandra Škrivanj; Ljubiša Ignjatović; Vera Dondur; Slavko Mentus; Gordana Ćirić-Marjanović
      Pages: 68 - 79
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Maja Milojević-Rakić, Danica Bajuk-Bogdanović, Bojana Nedić Vasiljević, Aleksandra Rakić, Sandra Škrivanj, Ljubiša Ignjatović, Vera Dondur, Slavko Mentus, Gordana Ćirić-Marjanović
      Semiconducting composites of nanostructured and granular polyaniline (PANI) with FeZSM-5 zeolite were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in water, without added acid and in an aqueous H2SO4 solution, in the presence of FeZSM-5, by using initial weight ratios aniline/FeZSM-5 of 1/1 and 1/5. These novel composite materials, in their as-synthesized (protonated) and deprotonated forms, were characterized by elemental, thermogravimetric and differential thermal analysis, scanning electron microscopy, FTIR and Raman spectroscopy, X-ray powder diffraction and conductivity measurements. The catalytic activity of the PANI/FeZSM-5 composites towards the oxidation of herbicide glyphosate with hydrogen peroxide has been investigated. A significant improvement of the catalytic activity of PANI/FeZSM-5 composites compared to that of pure PANI and FeZSM-5 was observed, manifested by the almost one order of magnitude more efficient oxidative degradation of glyphosate with hydrogen peroxide. The maximum of oxidized/decomposed amount of glyphosate was achieved in the presence of PANI/FeZSM-5 composite synthesized using an initial aniline/FeZSM-5 = 1/5 wt ratio. It has been shown that the method of synthesis and interactions between PANI and zeolite in this complex composite system, leading to more efficient electron transfer and hydrogen peroxide decomposition, are crucial for the catalytic properties of tested PANI/FeZSM-5 materials. It is shown that new PANI/FeZSM-5 composites present advanced catalyst materials for enhanced green catalytic degradation of pesticide/herbicide pollutants in environmental remediation systems.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.019
      Issue No: Vol. 267 (2018)
       
  • Microporous frameworks with conjugated π-electron skeletons for enhanced
           gas and organic vapor capture
    • Authors: Jianwei Guo; Xiong Li; Shuqin Fu; Rui Tong; Paul D. Topham; Jiawei Wang
      Pages: 80 - 83
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Jianwei Guo, Xiong Li, Shuqin Fu, Rui Tong, Paul D. Topham, Jiawei Wang
      Novel conjugated microporous frameworks based on adamantane (CMF-Ads) have been successfully synthesized under mild conditions. Eight-arm tetraphenyl “knots” and a conjugated π-electron skeleton endowed the target CMF-Ads with ultra-high thermal stability (up to 500 °C), high surface area (up to 907 m2 g−1), excellent CO2 uptake capacity of 15.13 wt % at 273 K and 1 bar, as well as superior organic vapor (benzene, hexane) adsorption. The ultra-high gas uptake capacity and selectivity of these CMF-Ads herein exceeds most conjugated microporous frameworks reported to date, highlighting their potential as materials for clean energy application.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.007
      Issue No: Vol. 267 (2018)
       
  • Acid-base bifunctional catalyst: Carboxyl ionic liquid immobilized on
           MIL-101-NH2 for rapid synthesis of propylene carbonate from CO2 and
           propylene oxide under facile solvent-free conditions
    • Authors: Tongtong Wang; Xuedan Song; Qunxing Luo; Xiaodong Yang; Siying Chong; Jie Zhang; Min Ji
      Pages: 84 - 92
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Tongtong Wang, Xuedan Song, Qunxing Luo, Xiaodong Yang, Siying Chong, Jie Zhang, Min Ji
      In terms of ‘green chemistry’ and ‘atom economy’, the cycloaddition of CO2 to yield cyclic carbonate without any additive is an eco-friendly way to utilize CO2. Unfortunately, the low CO2 capture quantity of common catalysts limited its catalytic efficiency. Herein, a novel acid-base bifunctional catalyst was successfully prepared by immobilizing ionic liquid on MIL-101-NH2 (IL/MIL-101-NH2) and tested for propylene carbonate (PC) rapid and facile synthesis from CO2 and propylene oxide (PO). The synergetic interaction between Lewis base with strong CO2 chemical capture capacity and Brønsted acid with strong hydrogen bond donor leads to the high catalytic efficiency of IL/MIL-101-NH2 for carbonate synthesis from CO2 and PO without any additive. The immobilization mode between MIL-101-NH2 and IL is energetically supported by the density functional theory (DFT) calculations. This design idea of specific catalyst and the acid-base synergetic strategy provides new insights into the design of powerful catalyst systems for the CO2 conversion.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.011
      Issue No: Vol. 267 (2018)
       
  • Facile synthesis of mesoporous 3D CoO/nitrogen-doped graphene aerogel as
           high-performance anode materials for lithium storage
    • Authors: Erzhuang Pan; Yuhong Jin; Yu Wang; Chenchen Zhao; Xin Bo; Mengqiu Jia
      Pages: 93 - 99
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Erzhuang Pan, Yuhong Jin, Yu Wang, Chenchen Zhao, Xin Bo, Mengqiu Jia
      CoO has been considered as a novel anode material for lithium storage due to its high theoretical capacity. Herein, mesoporous 3D CoO/nitrogen-doped graphene aerogel (CoO/NGA) is constructed by a facile solvothermal approach followed by subsequent annealing. The NGA is prepared by using dimethylmethanamide (DMF) as a reducing agent and nitrogen source. Ultrafine CoO nanocrystals are homogeneously distributed and tightly anchored on the 3D macroscopic NGA frameworks. The 3D NGA can not only effectively restrain the agglomeration of CoO nanocrystal but also accelerate ion and electron transport through 3D networks. Benefiting from the combine of the two characteristics, the unique CoO/NGA anode exhibits an outstanding cycling stability, showing a specific capacity of 896 mAh g−1 at 200 mA g−1 after 200 cycles.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.025
      Issue No: Vol. 267 (2018)
       
  • Molten salt assisted synthesis of microporous polyaniline nanosheets with
           superior gas sorption properties
    • Authors: Miao Zhang; Lin Liu; Xiaohua Ju; Teng He; Ping Chen
      Pages: 100 - 106
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Miao Zhang, Lin Liu, Xiaohua Ju, Teng He, Ping Chen
      Porous polyaniline (PANI) nanosheet has unique structure and properties that can be applied in gas separation, gas storage, and energy storage and conversion devices. To date, it is still a great challenge to construct microporous PANI nanosheet materials. Here, we present an inorganic salt template pyrolysis route for the direct synthesis of ultrathin PANI nanosheets with well-defined microporous structure from hexaaminobenzene monomer. The obtained PANI nanosheets give an ultrathin thickness of 1.6 nm, high surface area (∼395 m2 g−1), and well-defined microporous structure (centered at ∼0.54 nm). The PANI nanosheets with plenty of micropores exhibit superior gas sorption property for CO2 and CH4 at room temperature, which is also expected to improve the performances of PANI nanosheets in other application fields.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.023
      Issue No: Vol. 267 (2018)
       
  • Transparent, elastic and crack-free polymethylsilsesquioxane aerogels
           prepared by controllable shrinkage of the hydrogels in the aging process
    • Authors: Chaoshuai Lei; Junning Li; Chencheng Sun; Hailong Yang; Tao Xia; Zijun Hu; Yue Zhang
      Pages: 107 - 114
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Chaoshuai Lei, Junning Li, Chencheng Sun, Hailong Yang, Tao Xia, Zijun Hu, Yue Zhang
      Polymethylsilsesquioxane (PMSQ) aerogels have gained extensive attention owing to their improved mechanical properties, good optical transparency and low thermal conductivity. However, the aerogels with high densities prepared by the conventional sol-gel method are fragile and opaque due to the increase in the particles size and the decrease in the uniformity of pore structure. In this research, transparent PMSQ aerogels over a wide range of densities from 0.15 g/cm3 to 0.25 g/cm3 are prepared by controllable shrinkage of the hydrogels in the aging process. Resulted PMSQ aerogels have smaller particle and pore size than that prepared by the conventional method. Surprisingly, the light transmittance of the aerogels with the density of 0.25 g/cm3 at 550 nm wavelength is up to 70%. Meanwhile, the Young's modulus of the aerogel is up to 4.33 MPa. The strength and resilience compressed to 50% can be 3.57 MPa and 99%, respectively. The thermal conductivities of the aerogels prepared by the novel method increase from 18.7 mW m−1 K−1 to 32.9 mW m−1 K−1, with the density increasing from 0.15 g/cm3 to 0.25 g/cm3. These results would extend the range of practical applications for the high density PMSQ aerogels such as the transparent insulators.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.025
      Issue No: Vol. 267 (2018)
       
  • Orchestrating fluoride effect, secondary growth and microwave irradiation
           in the synthesis of EU-1/ZSM-48 intergrowth crystals for the conversion of
           dimethyl ether to olefins
    • Authors: Mohamed H.M. Ahmed; Oki Muraza; Koji Miyake; Yuichiro Hirota; Norikazu Nishiyama
      Pages: 115 - 123
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Mohamed H.M. Ahmed, Oki Muraza, Koji Miyake, Yuichiro Hirota, Norikazu Nishiyama
      A great decrease in the crystallization time of EU-1 zeolite to 10 h was achieved by coupling between the microwave-assisted hydrothermal synthesis and the addition of fluoride as crystallization promoter in the presence of 10% EU-1 seeds in alkaline media. Interesting characterization results were obtained by observing an octahedral coordination of Al incorporated with the fluoride presented in the synthesis in the form of AlO4F2. This finding was confirmed by analyzing the spectra of FTIR and 27Al MAS NMR which showed additional peak attributed to AlO4F2. The short crystallization time offered a significant decrease of EU-1 particle size to ∼500 nm as observed on FE-SEM. A pure phase of EU-1 was synthesized in the range of 25–100 Si/Al ratio. An intergrowth phase of EU-1 and ZSM-48 was observed on XRD when 200 Si/Al ratio gel was prepared. Excellent catalytic performance of DME conversion to olefins was achieved over the co-crystalline EU-1 and ZSM-48 sample. The sample showed exceptional stability for 360 min on stream compared with other samples and the highest olefins selectivity which reached to 78%.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.047
      Issue No: Vol. 267 (2018)
       
  • Effect of Ge/Si substitutions on the local geometry of Si framework sites
           in zeolites: A combined high resolution 29Si MAS NMR and DFT/MM study on
           zeolite Beta polymorph C (BEC)
    • Authors: Sarah R. Whittleton; Aurelie Vicente; Christian Fernandez; Somayeh F. Rastegar; Anna V. Fishchuk; Stepan Sklenak
      Pages: 124 - 133
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Sarah R. Whittleton, Aurelie Vicente, Christian Fernandez, Somayeh F. Rastegar, Anna V. Fishchuk, Stepan Sklenak
      We employed density functional theory/molecular mechanics (DFT/MM) calculations and 29Si magic-angle spinning (MAS) NMR spectroscopy to investigate the effect of single and multiple Ge/Si substitutions on the 29Si NMR parameters as well as the local geometry of SiO4 tetrahedra of the nearest (Ge-O-Si) and next-nearest (Ge-O-Si-O-Si) neighboring Si atoms. The influences of the Ge/Si substitutions are compared with the effects of the corresponding Al/Si substitutions (i.e., Al-O-Si and Al-O-Si-O-Si, respectively). Zeolite Beta polymorph C (BEC), containing double four-membered rings (D4Rs) and exhibiting three distinguishable T sites in the framework, was chosen for this study as a model of germanium containing zeolites. Our computations give a systematic downshift of the 29Si chemical shift of Si by 1–6 ppm for Ge-O-Si sequences. Furthermore, the contributions of two, three, and four Ge atoms as the nearest neighbors to the downshift of Si are not additive and the calculated downshifts lie in the intervals from 2 to 6 ppm, from 1 to 9 ppm, and from 5 to 11 ppm, respectively. Conversely, the contributions of two, three, and four Al atoms as the nearest neighbors are approximately additive. The downshifts caused by Ge nearest neighbors are less than half compared with the corresponding downshifts caused by Al. Moreover, our calculations show that there are no systematic contributions of Ge and Al as next-nearest neighbors (i.e., Ge-O-Si-O-Si and Al-O-Si-O-Si, respectively) to the 29Si chemical shift of Si, and not even the direction (sign) can be predicted without calculating the corresponding sequence.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.021
      Issue No: Vol. 267 (2018)
       
  • Mesoporous Cu-SBA-15 with highly ordered porous structure and its
           excellent CO2 adsorption capacity
    • Authors: Kripal S. Lakhi; Gurwinder Singh; Sungho Kim; Arun V. Baskar; Stalin Joseph; Jae-Hun Yang; Hamid Ilbeygi; Sujanya J.M. Ruban; Van T.H. Vu; Ajayan Vinu
      Pages: 134 - 141
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Kripal S. Lakhi, Gurwinder Singh, Sungho Kim, Arun V. Baskar, Stalin Joseph, Jae-Hun Yang, Hamid Ilbeygi, Sujanya J.M. Ruban, Van T.H. Vu, Ajayan Vinu
      CuOx loaded mesoporous silicas with highly ordered mesoporous structures (Cu-SBA-15) and different silicon to copper ratios were synthesized by using P123 as a template under mild acidic conditions. XRD and N2 sorption results confirm the well-ordered 2D mesoporous structure with a high specific surface area and a large pore volume. The pore diameter of Cu-SBA-15 increases from 7.9 to 8.5 nm with a concomitant decrease of the specific surface area from 865 to 802 m2/g as the amount of Cu in the silica framework is increased. We also show the introduction of Cu in the SBA-15 makes a significant change in the final morphology, which changes from rod to curve shaped morphology when the amount of Cu in the SBA-15 is increased. XRD results confirm the presence of CuO nanoparticles inside the nanochannels of SBA-15. The materials were used as adsorbents for high pressure CO2 adsorption at different temperatures −5, 0, 10 and 25 °C and pressures up to 30 bar. The highest CO2 adsorption of 27.6 mmol/g at −5 °C was achieved for Cu-SBA-15 sample with a n Si/Cu ratio of 5 and was found to be much higher than that of pure SBA-15 silica under similar conditions, illustrating the role of CuOx doping in the SBA-15 framework.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.024
      Issue No: Vol. 267 (2018)
       
  • Tailoring of ordered mesoporous silica COK-12: Room temperature synthesis
           of mesocellular foam and multilamellar vesicles
    • Authors: Maria Gracia Colmenares; Ulla Simon; Franziska Schmidt; Shirin Dey; Johannes Schmidt; Arne Thomas; Aleksander Gurlo
      Pages: 142 - 149
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Maria Gracia Colmenares, Ulla Simon, Franziska Schmidt, Shirin Dey, Johannes Schmidt, Arne Thomas, Aleksander Gurlo
      Ordered mesoporous silica materials are known for their high surface area and highly ordered structure. One of the main advantages of the synthesis of ordered mesoporous silica by soft-templating with amphiphilic molecules is the ability to tailor the mesostructure by using micellar swelling agents. In this context, the addition of hexane and polypropylene glycol (PPG) as micellar swelling agents in the facile room-temperature synthesis of COK-12 was studied to tailor the mesoporous structure of the system. Hexane was used as a micelle expander and as an agent to produce silica mesocellular foams (MCF), resulting in a material with “ink-bottle” pores with a larger diameter than that of the original COK-12, with up to 8.5 nm in cell diameter and 5.3 nm in window diameter. By adding PPG into the synthesis, a shift of the mesostructure of COK-12 from 2D hexagonal to a multilamellar vesicular (MLV) configuration was observed, resulting in the progressive formation of this type of material with increasing concentration of PPG.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.015
      Issue No: Vol. 267 (2018)
       
  • Desilication of *BEA zeolites using different alkaline media: Impact on
           catalytic cracking of n-hexane
    • Authors: H. Sammoury; J. Toufaily; K. Cherry; T. Hamieh; Y. Pouilloux; L. Pinard
      Pages: 150 - 163
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): H. Sammoury, J. Toufaily, K. Cherry, T. Hamieh, Y. Pouilloux, L. Pinard
      The desilication of two commercial nano- and one synthesized microcrystal *BEA zeolites via different alkaline solutions have led to several observations. In the nanocrystal *BEA zeolites, the use of NaOH alone reduced the crystallinity and microporosity, which was recovered after the use of pore directing agents as tetrapropylammonium bromide (TPABr). The use of tetrabutylammonium hydroxide (TBAOH) was not as much effective with NaOH as TPABr in terms of crystallinity and microporosity recovery, as it wasn't also as much effective as was NaOH alone in introducing intracrystalline mesopores to these nanocrystals. In the microcrystal series, the use of NaOH with TBAOH was seen to be more effective than NaOH alone or NaOH with TPABr. The increase of relative Brønsted acidity was observed at lower alkaline concentrations with a pronounced decrease at higher alkaline media. The company of the pore directing agents was seen to provoke the formation of new Lewis acid sites. In the cracking of n-hexane, the desilication treatments were not seen to improve the catalytic performance of the requested catalysts, as the slight deactivation of the catalysts was at the basis of coke formation. The activity was seen to drop due to even the diffusional limitations occurring or due to loss of acidity after desilication. More olefin and isomers products were produced despite of coke formed which was considered non-toxic being located inside the mesopores.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.022
      Issue No: Vol. 267 (2018)
       
  • Solid state transformations of (NH4, Pb)-clinoptilolite through heating
    • Authors: Antonio Brundu; Eleonora Sale; Guido Cerri
      Pages: 164 - 170
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Antonio Brundu, Eleonora Sale, Guido Cerri
      Three clinoptilolite-based materials, having Pb2+/NH4 + ratios of 1.60, 0.56 and 0.16, were prepared starting from a powder containing ≈90% of NH4-clinoptilolite. The samples were submitted to a set of thermal treatments of 2 h up to 1000 °C. Further treatments were performed at 900 and 1000 °C for 4, 8, 16 and 32 h. (NH4, Pb)-clinoptilolite underwent dehydration, de-ammoniation, and dehydroxylation, the latter accompanied by amorphization that occurred between 600 and 700 °C, whereas crystallization of new phases started at 800–900 °C. The products, obtained through solid state reactions, were: i) Pb-feldspar + cristobalite/tridymite + glass, when Pb2+/NH4 + ≥ 0.16; ii) mullite + cristobalite/tridymite + glass, when 0 ≤ Pb2+/NH4 + ≤ 1.60, hence both Pb-feldspar and mullite were obtained for 0.16 ≤ Pb2+/NH4 + ≤ 1.60. XRD data showed that, for a given composition, temperature and duration of the heating influenced the quantity of the phases formed, but also the occupancy of Pb- and T-sites of Pb-feldspar. Crystalline products (amorphous 10–12%) were obtained from all samples. When Pb2+/NH4 + ≥ 0.56, the highest amounts of Pb-feldspar and the lowest quantities of residual glass were recorded after 32 h at 900 °C, but a 2-h treatment at 1000 °C allowed to speed up the transformation, confining over 70% of lead within feldspar. The sample with Pb2+/NH4 + = 0.16 required 32 h at 1000 °C to reduce glass at 10%, but most of the lead (≈70%) remained in the amorphous fraction.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.026
      Issue No: Vol. 267 (2018)
       
  • High-throughput fabrication of zeolite thin films via ultrasonic nozzle
           spray deposition
    • Authors: Chon Hei Lam; Wan-Ju Hsu; Heng-Yu Chi; Yu-Hao Kang; Jiun-Jen Chen; Dun-Yen Kang
      Pages: 171 - 180
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Chon Hei Lam, Wan-Ju Hsu, Heng-Yu Chi, Yu-Hao Kang, Jiun-Jen Chen, Dun-Yen Kang
      Zeolite thin films with ordered nanopores and a low dielectric constant can serve as an insulation layer in microelectronic devices. However, the absence of a high-throughput deposition technique is a major technical hurdle in the industrial-scale production of zeolite thin films. Herein, we report on a scalable method, ultrasonic nozzle spray deposition (UNSD), which addresses this issue. A high-frequency standing wave introduced by the ultrasonic nozzle produces uniform sized droplets of the cast suspensions at a scale of tens to hundreds of micrometers, which results in a uniform thin film following the removal of the solvent. In this paper, we focus on the deposition of thin films comprising pure-silica zeolite MFI on a silicon wafer substrate. We systematically investigated how the quality of the zeolite thin films is affected by the composition of the cast suspensions and UNSD operating parameters. We identified the UNSD operating window that allows for the fabrication of uniform dense zeolite thin films at thicknesses ranging from hundreds of nanometers to 3 μm. We determined that zeolite MFI thin films prepared using UNSD outperformed those fabricated using conventional spin-on deposition in terms of uniform film thickness, low leakage current, and high Young's modulus.
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      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.031
      Issue No: Vol. 267 (2018)
       
  • High value activated carbons from waste polystyrene foams
    • Authors: Fabiano G.F. de Paula; Mateus C.M. de Castro; Paulo F.R. Ortega; Clara Blanco; Rodrigo L. Lavall; Ricardo Santamaría
      Pages: 181 - 184
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Fabiano G.F. de Paula, Mateus C.M. de Castro, Paulo F.R. Ortega, Clara Blanco, Rodrigo L. Lavall, Ricardo Santamaría
      Activated carbons (AC) with excellent textural properties have been obtained for the first time from waste polystyrene foam (PF), without any previous treatment, following a simple and conventional two-step procedure (formation of char followed by chemical activation). Even considering that the PF is not a graphitizable material, the best AC produced from this precursor has a very high BET surface area larger than 2700 m2 g−1 and a pore volume of 1.2 cm2 g−1, with a significant contribution of small mesopores. As a consequence, this AC reveals a surprising capacity to adsorption of relatively large molecules and a high specific capacitance when applied as a supercapacitor electrode. The maximum amount of adsorbed methylene blue obtained by batch equilibrium experiments are greater than 1 g g−1. In the context of the technical difficulties and low economic return of the reuse and recycling of waste PF, this work offers a strategic destination for this environmentally unfriendly residue.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.027
      Issue No: Vol. 267 (2018)
       
  • MoO3 nanoparticle formation on zeolitic imidazolate framework-8 by rotary
           chemical vapor deposition
    • Authors: Matteo Ciprian; Peng Xu; Somboon Chaemchuen; Rong Tu; Serge Zhuiykov; Philippe M. Heynderickx; Francis Verpoort
      Pages: 185 - 191
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Matteo Ciprian, Peng Xu, Somboon Chaemchuen, Rong Tu, Serge Zhuiykov, Philippe M. Heynderickx, Francis Verpoort
      For the first time, MoO3 nanoparticles (NPs) with a size ranging from 1.5 to 60 nm were deposited on spray dried zeolitic imidazolate framework-8 (ZIF-8) by rotary chemical vapor deposition (RCVD) in order to improve its photocatalytic performance. A direct effect of the deposition time on the metal oxide loading was observed. In a time frame between 0.9 and 2.7 ks the metal oxide loading can be increased from 1 to 3 wt%. All the MoO3-NPs/ZIF-8 catalysts were tested towards the methylene blue photodegradation using sunlight. MoO3-NPs/ZIF-8 3 wt% RCVD reached a conversion of 82% and 95% after 180 and 300 min, respectively.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.028
      Issue No: Vol. 267 (2018)
       
  • Synthesis of phosphorus-modified AFX zeolite using a dual-template method
           with tetraethylphosphonium hydroxide as phosphorus modification agent
    • Authors: Emi Mitani; Yoshitaka Yamasaki; Nao Tsunoji; Masahiro Sadakane; Tsuneji Sano
      Pages: 192 - 197
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Emi Mitani, Yoshitaka Yamasaki, Nao Tsunoji, Masahiro Sadakane, Tsuneji Sano
      Hydrothermal conversion of FAU zeolite was carried out in the presence of both 1,1'-(1,4-butanediyl)bis(1-azonia-4-azabicyclo[2,2,2]octane) (Dab-4) cation as a structure-directing agent and tetraethylphosphonium (TEP) cation as a phosphorus modification agent. By optimizing the synthesis parameters such as the TEPOH/SiO2, [Dab-4](OH)2/SiO2, NaOH/SiO2, and H2O/SiO2 ratios in the starting reaction mixtures, we successfully synthesized highly crystalline phosphorus-modified (P-modified) AFX zeolite with truncated hexagonal bipyramidal morphology. The P-modification of the AFX zeolite needed a TEP/(Dab-4+TEP) ratio higher than 0.9 because TEP cations have no structure-directing ability for the AFX phase. The obtained P-modified AFX zeolite with a Si/Al ratio of 5–6 and a P/Al ratio of 0.07–0.2 exhibited high thermal stability compared to the P-free one.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.033
      Issue No: Vol. 267 (2018)
       
  • Ambient temperature gas phase sulfonation: A mild route towards acid
           functionalized ordered mesoporous organosilica
    • Authors: Lennart Sandbrink; Timon Lazaridis; Marcus Rose; Regina Palkovits
      Pages: 198 - 202
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Lennart Sandbrink, Timon Lazaridis, Marcus Rose, Regina Palkovits
      Sulfonation is a versatile method for the production of acidic materials, e. g. for applications in catalysis. In this study different sulfonation techniques for the production of acidic ordered mesoporous materials are investigated. SBA-15-like mesoporous organosilanes bearing aromatic moieties are sulfonated in the liquid phase with oleum as well as in the gas phase under significantly milder conditions with sulfur trioxide. Functionalization via liquid phase sulfonation at elevated temperatures proceeds at the expense of partial or complete collapse of the pore system. In contrast, gas phase sulfonation with sulfur trioxide at ambient temperature allows for similar sulfonation yields, while maintaining the textural properties due to the milder reaction conditions. Overall, acid functionalization of mesoporous organosilica using a gas phase sulfonation route is reported for the first time, enabling both high acid capacities and preservation of the pore structure.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.030
      Issue No: Vol. 267 (2018)
       
  • Comparison study between a series of new type functional diatomite on
           methane adsorption performance
    • Authors: Yang Mu; Miao Cui; Shaoqing Zhang; Jing Zhao; Changgong Meng; Qi Sun
      Pages: 203 - 211
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Yang Mu, Miao Cui, Shaoqing Zhang, Jing Zhao, Changgong Meng, Qi Sun
      Organosilanes with different head groups and chemical properties, including phenyltriethoxysilane (PTES), aminopropyltriethoxysilane (APTES), and trimethylchlorosilane (TMCS), were used to modify the adsorption properties of diatomite (DE). Characterizations of the as-synthesized samples were investigated by scanning electron microscopy (SEM), infrared spectroscopy (IR), thermogravimetric analysis (TGA), nitrogen adsorption–desorption and solid-state 29Si magic angle spinning nuclear magnetic resonance (MAS NMR). SEM imagines show that the morphology of DE was remained during the modification. IR spectra provide clear evidence that they were indeed modified as intended. The results of TGA show that the weigh losses of all samples were increased after silylation. And the MAS NMR indicated that large amounts of isolated silanols condense with the organolsilanes, which further proved the organic groups have been loaded onto the diatomite. The adsorption experiments of methane by raw and three modified diatomite were also studied. Results showed that the adsorption amount increases constantly with the increasing of pressure and the equilibrium have not been reached at the room temperature. The adsorption data indicate that the sorption of CH4 on modified products and diatomite are dominated by multilayer coverage and they all fit the Freundlich isotherm equation well. The PTES-DE and APTES-DE have excellent CH4 adsorption capacity and they can reach the adsorption target proposed by DOE far below 35 bar, at 3 bar and 7.5 bar respectively. These two materials exhibit excellent adsorption performance for CH4 and have the potential to provide improved methods for reducing greenhouse gas emissions.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.037
      Issue No: Vol. 267 (2018)
       
  • Zeolitic imidazole Framework-8 (ZIF-8) fibers by gas-phase conversion of
           electroblown zinc oxide and aluminum doped zinc oxide fibers
    • Authors: Jani Holopainen; Mikko J. Heikkilä; Leo D. Salmi; Kaisu Ainassaari; Mikko Ritala
      Pages: 212 - 220
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Jani Holopainen, Mikko J. Heikkilä, Leo D. Salmi, Kaisu Ainassaari, Mikko Ritala
      Electroblowing was used to prepare ZnO and aluminum doped zinc oxide (AZO, 1–3 cation-% of Al) fibers. The as-blown fibers were calcined at 500 °C to obtain the target material. The average fiber diameters ranged from 240 ± 60 nm for ZnO fibers to 330 ± 80 nm for AZO with 3% Al. Smaller crystallite size was measured with x-ray diffraction for the Al doped fibers. Electroblowing was found out be an effective method to increase the fiber productivity over electrospinning and other methods reported in literature to prepare AZO fibers as a high production rate of 0.32 g/h was achieved. The ZnO and AZO fibers could be converted to zeolitic imidazole framework-8 [ZIF-8, zinc(2-methylimidazolate)2] by a solvent free thermal treatment in an autoclave under 2-methylimidazole (HmIM) vapor at 150 and 200 °C while preserving the fibrous structure. The conversion process to ZIF-8 occurred faster at higher temperatures and on fibers with smaller crystallite size. Depending on the conversion treatment time either ZnO/ZIF-8 and AZO/ZIF-8 core/shell fibers or ZIF-8 fibers could be obtained. At best the prepared ZIF-8 fibers had a very high BET specific surface area of 1340 m2/g.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.04.003
      Issue No: Vol. 267 (2018)
       
  • Adsorption of pure and predicted binary (CO2:CH4) mixtures on 13X-Zeolite:
           Equilibrium and kinetic properties at offshore conditions
    • Authors: Firas A. Abdul Kareem; A.M. Shariff; Sami Ullah; Nurhayati Mellon; L.K. Keong
      Pages: 221 - 234
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Firas A. Abdul Kareem, A.M. Shariff, Sami Ullah, Nurhayati Mellon, L.K. Keong
      The growth in energy demand for natural gas has led to the exploration of sub-quality natural gas reserves with high CO2 content up to 80% at the offshore condition with temperature and pressure approximately 50 °C and 70 bar. In this work, a gravimetric technique is used to study CO2 and CH4 adsorptions on 13× zeolites at 50 °C and up to 70 bar pressure as an adequate range for offshore operations. 13× zeolite shows high CO2 adsorption capacity with 5.226 mmol/g at 50 °C compared to 4.29 mmol/g at 70 °C. The same trend is noticed for CH4 adsorption on both temperatures. Four equilibrium isotherm models are used to analyze the adsorption data i.e. Langmuir, Freundlich, Toth, and Sips. Virial isotherm model is applied on the experimental data to illustrate the isosteric heat of adsorption and it shows an excellent agreement with R2 = 0.998 for 13× MSZ. Henry's law constant is estimated utilizing Virial coefficients, which shows higher molar selectivity ratio for CO2 on 13× with α ˜ 3.957 at 50 °C as compared to the α ˜ 3.736 at 70 °C. Extended Langmuir (EL) Model and Multisite Langmuir (MSL) models are applied for 30:70, 50:50, and 70:30 CO2:CH4 binary mixtures. The outcomes of MSL exhibit high agreement with the quadrupole and polarizability of the single component and the mixtures. The kinetic rate constant is estimated according to the applied LDF model at higher operational regions. The 13× MSZ shows feasibly good isosteric heat of adsorption, which might refer to the large surface area and pore volume that can accommodate CO2 at higher speed and quantity at offshore conditions.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.04.007
      Issue No: Vol. 267 (2018)
       
  • Structure and thermal stability in hydrophobic Pluronic F127-modified
           silica aerogels
    • Authors: Taína Z. Fermino; Carlos M. Awano; Leandro X. Moreno; Dimas R. Vollet; Fabio S. de Vicente
      Pages: 242 - 248
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Taína Z. Fermino, Carlos M. Awano, Leandro X. Moreno, Dimas R. Vollet, Fabio S. de Vicente
      Hydrophobic ambient pressure drying (APD) aerogels were prepared from hydrolysis of tetraethylorthosilicate (TEOS) in solutions with different concentrations of poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (F127). APD was carried out after silylation of wet gels with 20% by volume of hexamethyldisilazane (HMDZ) in n-hexane. The samples were analyzed by small-angle X-ray scattering (SAXS) and nitrogen adsorption. The APD aerogels obtained in this process were submitted to heat treatment at 300, 500, 700 and 900 °C to study the pores stability. The samples were characterized by nitrogen adsorption. Wet gels are formed by mass-fractal domains, with fractal dimension close to 2.1 and characteristic size (ξ) spanning from about 9 nm (for the gel prepared without the addition of F127) up to values that exceed the maximum limit of the SAXS experimental setup, with increasing the concentration of F127. Nitrogen adsorption data showed that the pore volume (V p) and the mean pore size (l p) of the aerogels increased with increasing the concentration of F127. The drying process diminished the characteristic size ξ and increased the dimension D of the mass-fractal domains and the size (r 0) of the primary particles of the aerogels with respect to the wet gels. The characteristic size ξ of the mass-fractal of the aerogels was found significantly larger with increasing the concentrations of F127. Thermally treated aerogels exhibited a similar general behavior with temperature independent of the concentration of F127. The porosity was found fairly stable up to about 500 °C. The porosity started to be eliminated at 700 °C and it was found practically collapsed at 900 °C. The silylation layer on the silica surface of the present APD aerogels was promptly eliminated at about 350 °C yielding complete loss of hydrophobicity.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.039
      Issue No: Vol. 267 (2018)
       
  • Pore structure development of silica particles below the isoelectric point
    • Authors: A. Lazaro; K. Sato; H.J.H. Brouwers; J.W. Geus
      Pages: 257 - 264
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): A. Lazaro, K. Sato, H.J.H. Brouwers, J.W. Geus
      The textural properties of amorphous silica play a fundamental role in its final properties and, therefore, in its possible applications. The aim of this study is to gain comprehensive understanding about how the process conditions influence the pore structure of silica synthesized below the isoelectric point and find possible solutions to tailor the final properties of nano-silica. This study was conducted using the mineral olivine as silica source and dissolving it in sulfuric acid. This synthesis method is an interesting and sustainable alternative to the existing commercial methods. This nano-silica exhibits a specific surface area in the range of 100–500 m2/g and a pore size distribution of 1–100 nm for silicas with a purity above 99%. At the beginning of the reaction, silica is microporous and mesoporous, showing no macroposity. As the reaction conversion progresses, silica particles become larger and macroporous, and internal porosity is developed. The process conditions have an important influence on the textural properties of nano-silica. By modifying the process conditions the small mesopores can be removed featuring no porosity below 9 nm and the large pores can be reduced to pore sizes as small as 30 nm. The possibility of tailoring the porosity of silica in this large range makes this material suitable for a wide range of applications.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.031
      Issue No: Vol. 267 (2018)
       
  • Corrigendum to “Rapid one-pot synthesis of ultrafine titania
           nanocrystals and their conversion into transparent mesoporous thin layer
           films” [Microporous Mesoporous Mater. 261 (2018) 207–213]
    • Authors: Yoshitaka Kumabe; Masataka Ohtani; Kazuya Kobiro
      Pages: 265 - 266
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Yoshitaka Kumabe, Masataka Ohtani, Kazuya Kobiro


      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.033
      Issue No: Vol. 267 (2018)
       
  • Organic groups influencing microporosity in organosilicas
    • Authors: A. Petra Dral; Johan E. ten Elshof
      Pages: 267 - 273
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): A. Petra Dral, Johan E. ten Elshof
      The micropore structure of a series of organosilica materials with various organic groups in bridging (methylene, ethylene, hexylene, octylene, p-phenylene) and terminal (methyl, n-propyl) positions was analyzed and compared to that of inorganic amorphous silica. Vapor thermogravimetry with water, methanol, 1-propanol and cyclohexane vapors was used to measure accessible pore volumes, pore entrance sizes and surface chemistries. Gas pycnometry with He, Ar and N2 was used to measure skeletal densities, semi-quantitative surface-to-volume ratios and surface areas, pore entrance sizes and semi-quantitative pore cavity sizes. Conventional adsorption isotherms were measured for N2 at −196 °C to check for mesoporosity and for CO2 at 0 °C to obtain Brunauer-Emmett-Teller surface areas for comparison. The known classification of 1) short or rigid organic bridges that open up the pore structure, 2) longer and more flexible bridges that cause pore filling and 3) terminal organic groups that reduce pore formation is further specified. The incorporation of any organic group in the silica network increased the dispersity in micropore entrance sizes as compared to inorganic silica in the probed size range. A critical discussion is given of the commonly accepted ‘spacing concept’ of organic bridges.
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      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.03.036
      Issue No: Vol. 267 (2018)
       
  • A porous and luminescent metal-organic framework containing triazine group
           for sensing and imaging of Zn2+
    • Authors: Tianen Fan; Tifeng Xia; Qi Zhang; Yuanjing Cui; Yu Yang; Guodong Qian
      Pages: 1 - 6
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Tianen Fan, Tifeng Xia, Qi Zhang, Yuanjing Cui, Yu Yang, Guodong Qian
      The rapid development of functionalization of lanthanide metal organic frameworks (Ln-MOFs) offers the potential for biomarkers sensing. It is closely associated with biology science and clinic medicine. In this work, a porous and luminescent terbium metal-organic framework TbTATB has been designed and solvothermally synthesized. The PXRD results demonstrated the commendable stability of this sensor. Enhanced luminescence of TbTATB origin from Tb3+ was observed in the presence of Zn2+, which is a kind of biologically important ion. This turn-on pattern was utilized for sensing Zn2+. TbTATB exhibited excellent sensitivity and selectivity towards Zn2+ in aqueous solution with the detection limit of 10.5 nM. What's more, it has fairly acceptable biocompatibility which was fully verified by cytotoxicity test. In the state of coexistence with living cells, visible increased green light of TbTATB emerged after the addition of Zn2+, while the survival state of cells was hardly disturbed. Markedly, this is the first time that a luminescent Tb-MOF can act as a sensor for sensing and imaging of Zn2+ ions simultaneously. What's more, the results also guide a new application direction of MOFs and supply a new way for the detection of other analytes in biological systems.
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      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.050
      Issue No: Vol. 266 (2018)
       
  • Efficient thiophene capture with a hydrophobic Cu-BTC-(n)Br adsorbent in
           the presence of moisture
    • Authors: Le Yu; Qing Liu; Wei Dai; Ning Tian; Na Ma
      Pages: 7 - 13
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Le Yu, Qing Liu, Wei Dai, Ning Tian, Na Ma
      A novel hydrophobic adsorbent, Cu-BTC-(n)Br, was successfully synthesized by Cu(NO3)2 (metal ions source) and BTC-(n)Br (organic ligand) using a hydrothermal synthesis technology. Nitrogen adsorption-desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and water contact angle are employed to characterize our obtained materials. Successful modification of these certain materials has been confirmed and the structural changes of them have been further explored. The efficient adsorption properties of as-prepared adsorbents for thiophene were evaluated by means of batch experiments. Compared with undressed Cu-BTC, Cu-BTC-(n)Br showed distinguished hydrophobicity and remarkable adsorption effectivity under aqueous circumstance. In addition, the adsorption process performance could be perfectly described by Langmuir adsorption model and pseudo-second-order equation. The hydrophobic Cu-BTC-(n)Br material might be a hopeful desulphurizer for real fuel in the presence of moisture.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.032
      Issue No: Vol. 266 (2018)
       
  • Intercalation and in situ formation of coordination compounds with ligand
           8-hydroxyquinoline-5-sulfonic acid in the interlayer space of layered
           silicate magadiite by solid-solid reactions
    • Authors: Yifu Zhang; Qiushi Wang; Shengnan Gao; Hanmei Jiang; Changgong Meng
      Pages: 14 - 23
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Yifu Zhang, Qiushi Wang, Shengnan Gao, Hanmei Jiang, Changgong Meng
      Intercalation and in situ formation of three fluorescent complexes, Al(III)-, Ca(II)- and Zn(II)-8-hydroxyquinoline-5-sulfonic acid (M-8HqS, M = Al, Ca and Zn) in the interlayer spaces of magadiite (mag) were synthesized by solid-solid reactions between metal ions exchanged mags (M-mag, M = Al, Ca and Zn) and 8HqS at room temperature. The intercalation and in situ formation of 8HqS molecules into the interlayer spaces of M-mags were evaluated by XRD, ICP-AES, EDS, elemental mappings, TG/DTA, elemental analysis, FE-SEM, FTIR, UV-Vis, PL and XPS. Results show that the basal spacings of the intercalated composites increase after the intercalation of 8HqS into M-mags. A new peak at 1461 cm−1 is observed, supporting the formation of the coordination complexes between 8HqS and metal cations. The slight shift of the absorption and luminescence bands of the complexes suggests the different microstructures including molecular packing of the complexes in the interlayer spaces of mags, which indicating that the process is a host-guest interaction. The amount of 8HqS in the intercalated compounds is different due to the diversification of coordination ability of metal ions, and the order of the coordination ability of these three metal ions is Ca2+ > Zn2+ > Al3+. The amount of the metal cations (Al3+, Ca2+ and Zn2+) in the interlayer of mag is enough for the in situ complex formation of M-8HqS complexes. Thus, the intercalation and in situ formation of M-8HqS complexes (M = Al, Ca and Zn) in the interlayer space of mag are successfully achieved in the present work.
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      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.038
      Issue No: Vol. 266 (2018)
       
  • Selective pore filling of mesoporous CMK-5 carbon studied by XRD:
           Comparison between theoretical simulations and experimental results
    • Authors: Christian Weinberger; Marc Hartmann; Sai Ren; Thomas Sandberg; Jan-Henrik Smått; Michael Tiemann
      Pages: 24 - 31
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Christian Weinberger, Marc Hartmann, Sai Ren, Thomas Sandberg, Jan-Henrik Smått, Michael Tiemann
      It is possible to infiltrate a guest species selectively in one pore system of bimodal mesoporous CMK-5 carbon by an optimized nanocasting procedure. The selective filling has a drastic impact on the low-angle X-ray diffraction pattern of this novel class of materials. The structures of CMK-5, CMK-5 composite materials (sulfur and SnO2 as guest species), and CMK-3 carbon were simulated to investigate the influence of the pore filling with different guest species on the diffraction pattern and compared with experimental results. Additionally, the impact of structural defects is taken into account. The nature of the guest species strongly influences the relative intensity of the diffraction peaks. It turns out that the diffraction patterns of sulfur-carbon composite materials are nearly identical as those of CMK-3 carbon, which is attributed to a similar electron density of carbon and sulfur. Thus, sulfur is an ideal guest species to investigate the selective pore filling in CMK-5 carbon.
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      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.035
      Issue No: Vol. 266 (2018)
       
  • Influence of pretreatment and reaction conditions on the catalytic
           activity of HAlBEA and CoHAlBEA zeolites in vinyl chloride formation from
           1,2-dichloroethane
    • Authors: Izabela I. Kamińska; Dmytro Lisovytskiy; Laetitia Valentin; Christophe Calers; Yannick Millot; Emil Kowalewski; Anna Śrębowata; Stanislaw Dzwigaj
      Pages: 32 - 42
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Izabela I. Kamińska, Dmytro Lisovytskiy, Laetitia Valentin, Christophe Calers, Yannick Millot, Emil Kowalewski, Anna Śrębowata, Stanislaw Dzwigaj
      HAlBEA and CoHAlBEA zeolite catalysts treated at 523 K or 873 K for 3 h in Ar, H2/Ar or air flows, respectively, were investigated in catalytic dehydrochlorination of 1,2-dichloroethane (DCE). The dehydrochlorination of DCE on these zeolite catalysts resulted in almost 100% selectivity to vinyl chloride (VC) monomer. It was demonstrated that different conditions of pretreatment of zeolite catalysts resulted in varied amount of Lewis and Brønsted acid sites responsible of the catalytic activity, stability and selectivity. HAlBEA and CoHAlBEA zeolites treated in the Ar flow showed the best activities in the dehydrochlorination of DCE, while the same zeolites treated in the air flow demonstrated the best time-on-stream stability. To clarify the reasons of differences in the catalytic behavior of HAlBEA and CoHAlBEA treated in the various conditions N2 physisorption, XRD, TPH, TEM, XPS, NMR and FTIR measurements were performed.
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      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.041
      Issue No: Vol. 266 (2018)
       
  • Silica beta synthesized under alkaline conditions
    • Authors: Baorong Wang; Min Lin; Jianming Yang; Xinxin Peng; Bin Zhu; Yao Zhang; Changjiu Xia; Weilin Liao; Xingtian Shu
      Pages: 43 - 46
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Baorong Wang, Min Lin, Jianming Yang, Xinxin Peng, Bin Zhu, Yao Zhang, Changjiu Xia, Weilin Liao, Xingtian Shu
      Zeolite β is an important material in catalysis, however the material with molar ration of silicon and aluminum more than 200 is difficult to synthesize. Typically, the pure silica β and heteroatom zeolite β are prepared at near neutral pH using HF as the mineralization agent. However, the HF is highly toxic and corrosive, and the zeolites formed are usually more than 10 μm. In this paper, alkaline and fluorine-containing salts was applied, and pure silica β was hydrothermally synthesized from a basic precursor. The silica resource and alkali metal cations in the precursor would influence the crystallization process, tetraethyl orthosilicate and sodium cations are preferred. The pure silica β is plate-like, the crystals formed on the third day are about 50 × 300 × 300 nm, which keep growing with the time, and pure silica zeolite β with uniform size of about 200 × 700 × 700 nm are synthesized in a week. More importantly, the pure silica β is defects-free, and it's highly hydrophobic.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.049
      Issue No: Vol. 266 (2018)
       
  • Regulation of the adsorption affinity of metal-organic framework MIL-101
           via a TiO2 coating strategy for high capacity adsorption and efficient
           photocatalysis
    • Authors: Na Chang; Hao Zhang; Meng-Shan Shi; Jia Li; Chen-Jia Yin; Hai-Tao Wang; Liang Wang
      Pages: 47 - 55
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Na Chang, Hao Zhang, Meng-Shan Shi, Jia Li, Chen-Jia Yin, Hai-Tao Wang, Liang Wang
      TiO2-MIL-101 nano-composite was synthesized through the growth of TiO2 crystals on MIL-101 substrate under solvothermal conditions, and was applied into the adsorption and photocatalytic degradation of methylene blue (MB), rhodamine B (RhB) and crystal violet (CV). The fabricated TiO2-MIL-101 nano-composite was characterized by thermogravimetric analysis (TGA), X-ray diffractometry (XRD), fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDAX), scanning electron microscope (SEM), transmission electron microscopy (TEM) and N2 adsorption experiments. As a result, we found that TiO2-MIL-101 nano-composite remained good porosity because of the MIL-101 substrate, and the TiO2 crystals were coated on the surface of MIL-101 without agglomeration. Furthermore, on basis of experiments, remarkable enhancement of adsorption affinity of TiO2-MIL-101 towards MB, RhB and CV could be mainly attributed to the regulation of the surface charge compared to original MIL-101 materials after coated by TiO2 crystals. Meanwhile, the fabricated TiO2-MIL-101 exhibited excellent photocatalytic activity for the degradation of MB, RhB and CV based on the TiO2 coatings.
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      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.051
      Issue No: Vol. 266 (2018)
       
  • Enhanced mass transfer on hierarchical porous pure silica zeolite used for
           gas separation
    • Authors: Jiangfeng Yang; Ning Yuan; Mai Xu; Jiaqi Liu; Jinping Li; Shuguang Deng
      Pages: 56 - 63
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Jiangfeng Yang, Ning Yuan, Mai Xu, Jiaqi Liu, Jinping Li, Shuguang Deng
      Two types of ultra-high silica silicalite-1 (2000–4400 SiO2/Al2O3) were prepared using a seed crystal synthesis method; silicalite-1-M, which is microporous (0.5 nm) and silicalite-1-H, which is hierarchical porous (0.5 nm and 10–15 nm). From the experimental results, silicalite-1-H/M have almost the same adsorption isotherms for CO2, CH4, C2H6 and N2, surface area and equilibrium adsorption selectivity, however, silicalite-1-H has a shorter adsorption equilibrium time when compared with silicalite-1-M at a given pressure, which shows a mass transfer enhancement phenomenon due to its mesoporous structure. A mixed gas breakthrough test and simulation was carried out to verify the mass transfer upgrade theory to determine whether the material could be applied for adsorption separation. Interestingly, their performances on the breakthrough experiment were different; silicalite-1-H has a shorter breakthrough time for CO2, CH4, C2H6 and N2 when compared with silicalite-1-M. All the experiment data are consistent with the simulation results. A variety of flow rates were used to investigate and compare the breakthrough time and hold time, and the separation efficiency of CO2/CH4, CH4/N2 and CH4/C2H6 was improved based on the use of the hierarchical porous sorbent over a certain flow rate range.
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      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.030
      Issue No: Vol. 266 (2018)
       
  • Pd NPs supported on N-doped carbon layer coated ZrSBA-15 for efficient
           heterogeneous catalysis reactions
    • Authors: Yan-Yun Meng; Qing-Da An; Zuo-Yi Xiao; Shang-Ru Zhai; Zhan Shi
      Pages: 64 - 74
      Abstract: Publication date: August 2018
      Source:Microporous and Mesoporous Materials, Volume 266
      Author(s): Yan-Yun Meng, Qing-Da An, Zuo-Yi Xiao, Shang-Ru Zhai, Zhan Shi
      Through hydrothermal synthesis and impregnation-reduction processes, a series of Pd-based nanocomposites using N-doped carbon layers coated ZrSBA-15 as the supports have been manufactured, aiming to upgrade the catalytic activity and stability of the catalysts. Pentaethylenehexamine (PEHA) was served as a nitrogen source to generate N-doped carbon (CN) layers that were pre-deposited into the acidic platelet framework ZrSBA-15, and then followed by introducing Pd0 nanoparticles (NPs) onto it, finally leading to the formation of target composite Pd/CN-ZrSBA-15. The samples were characterized by XRD, TEM, SEM, N2 adsorption-desorption isotherm, FTIR, XPS etc. The catalytic performance of as-prepared catalysts was evaluated by the aerobic oxidation of benzyl alcohol and the reduction of 4-NP, respectively. Duo to the platelet-like morphology with shortened channels and the modification of N-doped carbon layers, which could effectively decrease pore blocking in the process of preparation and reactions as well as enhance the metal-support interaction, the derived catalysts could afford 85% conversion of benzyl alcohol and 100% selectivity of benzaldehyde, and the conversion of 4-NP was also up to 96%. More remarkably, the catalysts could be reused at least ten times without significantly loss in catalytic activity.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
      DOI: 10.1016/j.micromeso.2018.02.042
      Issue No: Vol. 266 (2018)
       
  • Enhanced activity of CO2 hydrogenation to CH4 over Ni based zeolites
           through the optimization of the Si/Al ratio
    • Authors: M.C. Bacariza; J.M. Lopes Henriques
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): M.C. Bacariza, I. Graça, J.M. Lopes, C. Henriques
      The effect of the Y zeolite framework composition (Si/Al ratio) on the catalytic performances of 15%Ni-based samples for the CO2 methanation reaction was studied. Different USY commercial zeolites with global Si/Al ratios ranging from 3 to 38 were then impregnated with the same Ni content and deeply characterized, namely by ICP analysis, TGA-DSC, XRD, N2 adsorption, CO2 adsorption, H2-TPR, DRS UV–Vis and TEM. Zeolites were also ion-exchanged with different compensating cations (Na+ and Cs+). It was observed that higher Si/Al ratio lead to lower affinity of the zeolites to water, lower basicity and also to the presence of mesopores able to locate some of the Ni particles. The catalytic performances were verified to be remarkably favoured by higher Si/Al ratios, regardless the compensating cation present on the zeolite supports. This could be explained by the lower surface affinity of high Si/Al ratio zeolites to the produced adsorbed water molecules, which should normally induce an inhibitory effect on the transformation process. Therefore, the effect of the hydrophobicity of the zeolites resulting from the lower Al content appears to be more preponderant for the rate of the reaction than the decrease of basicity (reported in the literature as a relevant factor for methanation). In addition, no sintering or loss of crystallinity was observed after the catalytic tests. Thus, this work clearly shows that important improvements on the catalytic performance of zeolites for the CO2 methanation can be achieved by adjusting their properties, namely the Si/Al ratio.
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      PubDate: 2018-04-15T06:33:47Z
       
  • Scaling-up of mesoporous silica films via an eco-efficient UV processing
           method. Part 2: Photoinduced calcination
    • Authors: Mathilde Sibeaud; Rigolet Michelin Lebeau Vidal Abraham Chemtob
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Mathilde Sibeaud, C. Croutxé-Barghorn, S. Rigolet, L. Michelin, B. Lebeau, L. Vidal, Abraham Chemtob
      We describe a fast photocalcination process to prepare highly ordered silica mesoporous films through the use of a low-pressure amalgam arc (λ: 185/254 nm). Because radiant power is 2–3 times higher than conventional low-pressure UV lamps, the elimination of the PEO-b-PPO-b-PEO copolymer template in the 2D hexagonal hybrid film has been completed within 50 min, without damage to the mesostructure. The degradation kinetics are impacted by film thickness and irradiance, but hardly copolymer concentration. Compared to thermocalcination, a narrower pore size distribution and lower energy consumption have been found. Photodegradation mostly originates from a photoablation mechanism induced by radiation at 185 nm, while oxidation due to photogenerated reactive oxygen species plays a minor role. Photocalcination has been combined with an initial photoinduced mesostructuration (detailed in Part 1: Microporous Mesoporous Mater., 257 (2017) 42–50), resulting in an unprecedented “all UV” method to mesoporous silica films. The final process relies on dual wavelength photoactivation: UVB to form the hybrid copolymer/silica network, a flash intermediate thermal consolidation, and UVC to decompose the copolymer chains.
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      PubDate: 2018-04-15T06:33:47Z
       
  • Ammonium tagged Hoveyda-Grubbs catalysts immobilized on magnetically
           separable core-shell silica supports for ring-closing metathesis reactions
           
    • Authors: Bengi
      Abstract: Publication date: 1 September 2018
      Source:Microporous and Mesoporous Materials, Volume 267
      Author(s): Bengi Özgün Öztürk
      Ammonium tagged Hoveyda-Grubbs (Ru-1) catalyst was immobilized on core-shell structured silica gel bearing a magnetic nano-sized α-Fe2O3 core via non-covalent interactions. Core-shell silica gel materials were synthesized using a two-step coating procedure of α-Fe2O3 in the presence of cationic (dodecyl trimethyl ammonium chloride, DTMAC) and non-ionic (Synperonic F108) surfactants and tetraethoxysilane (TEOS) as the silica source. Double SiO2 coated SiO2(2)@α-Fe2O3 supports with a high surface area of 646 m2/g and pore size/volumes of 2.88 nm/0.393 cm3 were obtained after removal of template surfactants from silica gel by extraction. Supported catalyst, Ru-1@SiO2(2)@α-Fe2O3, was found to be very active in ring-closing metathesis (RCM) reactions of diethyl diallyl malonate (DEDAM) and various dienes. The catalyst can be easily separated from the reaction mixture with the aid of a magnet and was reusable up to eight times with low Ru leaching levels.
      Graphical abstract image

      PubDate: 2018-04-15T06:33:47Z
       
 
 
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