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Journal Cover Microporous and Mesoporous Materials
  [SJR: 1.306]   [H-I: 102]   [6 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1387-1811
   Published by Elsevier Homepage  [2817 journals]
  • Storage and delivery of nitric oxide by microporous titanosilicate ETS-10
           and Al and Ga substituted analogues
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Moisés L. Pinto, Ana Cristina Fernandes, Fernando Antunes, João Pires, João Rocha
      Exogenous administration of nitric oxide may be a therapy for several pathologies because this molecule regulates many biological systems. Here, the storage and release of NO by microporous titanosilicate ETS-10 and samples where the silicon was substituted by aluminium (ETAS-10) or gallium (ETGS-10) are studied. The Al- and Ga-doped materials exhibit an increase in the storage capacity of 95% and 55%, respectively, the highest values observed, so far, for microporous titanosilicates. ETAS-10 releases more NO and ETGS-10 almost the same amount as ETS-10. In ETAS-10 and ETGS-10, the irreversibly adsorbed NO amount increases relatively to ETS-10. Tests of NO release in haemoglobin solutions indicate that biologically relevant amounts are release and that ETS-10 and ETGS-10 display a release slower than ETAS-10, more adequate for a sustained delivery. Cytotoxicity studies show that the samples have very low toxicity (cell viability above 87%, after 72 h) at high concentration (0.45 mg cm−3). Tests at variable ETS-10 concentration further confirm the low cytotoxicity of this material, even at high concentrations (up to 1.8 mg cm−3).
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      PubDate: 2016-04-28T01:55:24Z
       
  • Bifunctional periodic mesoporous organosilicas with sulfide bridges as
           effective sorbents for Hg(II) extraction from environmental and drinking
           waters
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Mustafa Imamoglu, Damián Pérez-Quintanilla, Isabel Sierra
      A well-ordered two-dimensional hexagonal periodic mesoporous organosilica have been prepared with a high content of disulfide groups in the pore wall (PMO-S-S). This material was obtained by co-condensation of bis(triethoxysylilpropyl)disulfide and tetraethyl orthosilicate under acidic conditions, using non-ionic surfactant P123 as the template. In order to obtain bifunctional disulfide-bridged materials (PMO-S-S-MTTZ and PMO-S-S-MP), the PMO-S-S was modified in a second step with the organic derivatives of 5-mercapto-1-methyltetrazole (MTTZ) or 2-mercaptopyridine (MP) with sulphur and nitrogen active groups in their molecular structures. The characterization of the materials was carried out by XRD, TEM and SEM, nitrogen adsorption-desorption isotherms, 13C MAS-NMR, 29Si MAS-NMR, FTIR, elemental and thermogravimetric analysis. All prepared materials showed excellent adsorption efficiency and selectivity for Hg(II). The results confirmed the existence of additional active sulphur and nitrogen groups on the material surface, in addition to the disulfide groups of the framework, gave a significant enhancement of Hg(II) maximum adsorption capacity of the materials, being the highest Hg(II) adsorption capacity obtained 437 mg g−1 at pH 5. The prepared materials could be potential sorbents for the extraction of this heavy metal from environmental and drinking waters.
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      PubDate: 2016-04-28T01:55:24Z
       
  • Titania-silica monolithic multichannel microreactors. Proof of concept and
           fabrication/structure/catalytic properties in the oxidation of
           2,3,6-trimethylphenol
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Agnieszka Koreniuk, Katarzyna Maresz, Klaudia Odrozek, Julita Mrowiec-Białoń
      Titania-silica monoliths with 3D hierarchical porosity in μm and nm scales were fabricated using either direct or post-synthesis method, to find that they enable very fast continuous-flow oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-1,4-benzoquinone with hydrogen peroxide as the oxidant. Extensive characterization of the monoliths using N2 adsorption, mercury porosimetry, SEM, energy dispersive X-ray mapping, FT-IR and UV–Vis spectroscopy showed a strong impact of the fabrication method on the structural properties and also coordination/dispersion of the titanium ions incorporated into the silica. Systematic study of the monolithic microreactors and corresponding powders in the continuous-flow and batch systems, revealed a large complexity of performance/structure/catalytic properties relationships. A direct method resulted in titanium active centres highly dispersed in microporous skeleton, and therefore larger TOF, compared to the surface titanium entities in monoliths obtained from the post-synthesis approach. However, owing to the lower porosity and much smaller flow-through (macro)pores the pressure drops were almost two orders of magnitude larger. The highly porous monolithic microreactors fabricated by the post-synthesis incorporation of titanium appeared to be superior; the substrate conversions of 85% were obtained in about 12 min compared to those of ca. 75% obtained in batch systems after 1 h. This could be explained by very intensive mass transport in macro- and mesopore size scales.
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      PubDate: 2016-04-28T01:55:24Z
       
  • Polyethyleneglycol grafting of y-alumina membranes for solvent resistant
           nanofiltration
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Cheryl R. Tanardi, Romina Catana, Mihai Barboiu, André Ayral, Ivo F.J. Vankelecom, Arian Nijmeijer, Louis Winnubst
      A method is presented for grafting mesoporous γ-alumina (pore size 5 nm), supported on an α-alumina ceramic membrane, with polyethylene glycols (PEG). The grafting performance of γ-Al2O3 powders with various PEG grafting agents, having different molecular weights, alkoxy groups, and ureido functionality, was analyzed by TGA, 29Si-NMR, FTIR, and the BET method. FTIR analysis indicated that grafting has occurred. It was found that the molecular weight, the presence of an ureido functionality and the number of hydrolyzable groups of the grafting agents influenced the grafting density. The highest grafting density in this work was obtained by using a silylated ureido PEG with the shortest chain length (n = 10), while the number of alkoxy groups of the grafting agents influenced the structural configuration of the grafted moiety. The grafted membrane surface showed a hydrophilic character. A decrease in solvent permeation of both ethanol and hexane after grafting was observed, due to the presence of the grafted moiety inside the membranes reducing the membrane pore diameter. The permeability with respect to different types of solvents (polar and nonpolar) was investigated. Lower permeability of ethanol than hexane was observed accompanied by a higher retention of Sudan Black in ethanol than in hexane. This effect is explained by the difference in solvent sorption in the grafted moiety for different types of permeating solvents.
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      PubDate: 2016-04-28T01:55:24Z
       
  • In vitro stimulation of MC3T3-E1cells and sustained drug delivery by
           a hierarchical nanostructured SiO2CaOP2O5 scaffold
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): M. Lourdes Ramiro-Gutiérrez, Leonor Santos-Ruiz, Sara Borrego-González, José Becerra, Aránzazu Díaz-Cuenca
      A hierarchical scaffold, SP1_h_HA, consisting of a biomimetic nano-hydroxyapatite surface coating growth onto a reticulated structure having a nano-organized porous texture was fabricated and functionally studied in vitro using osteoprogenitor cells. Three scaffold materials (designated as SP0_l, SP0_h and SP1_h) were also prepared through modifications of the processing variables as control materials. The scaffolds were characterized showing well-interconnected micron-sized voids and a nano (4–6 nm)-organized porosity. In order to evaluate potential local risks and performance over mammalian cells the scaffolds were studied in comparison with a commercial clinical grade scaffold material, ProOsteon® 500R. MC3T3-E1 pre-osteoblast viability was evaluated using the resazurin assay and field emission gun scanning electron microscopy (FEG-SEM), showing in all cases good proliferative response. Alkaline phosphatase (ALP) production and analysis of the differentiation marker osteocalcin (OC), both in non-osteoinductive and osteoinductive media, were assessed using colorimetric and RT-PCR methods. The implementation of the new scaffold processing variables enhanced ALP activity with respect to the SP0_l control material. The cell proliferation, ALP activity, and mRNA OC expression response to SP1_h_HA scaffold were higher than those observed after the use of ProOsteon® 500R. In addition, SP1_h_HA scaffold showed a two stage sustained release of gentamicin sulfate (GS) instead of the quick release shown by ProOsteon® 500R. These results suggest that our synthesized scaffold could be effective for antibiotic delivery and bone regeneration and a better option than ProOsteon® 500R.
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      PubDate: 2016-04-24T02:05:32Z
       
  • Synthesis of mesoporous geopolymers containing zeolite phases by a
           hydrothermal treatment
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): N.K. Lee, Hammad R. Khalid, H.K. Lee
      The present study investigates the synthesis of mesoporous geopolymers containing different nano-crystalline zeolite phases. A hydrothermal treatment procedure was utilized to synthesize the mesoporous geopolymers using fly ash, slag and alkaline solution. The effects of slag addition and molar ratio of alkaline solution on the microstructure and mechanical strength of the geopolymers were investigated and evidenced by XRD analysis, compressive strength and nitrogen adsorption tests. The test results showed that the geopolymers incorporating fly ash and slag consisted of Na-P1 and Sodalite zeolite phases, and had the characteristic of mesoporous materials (2 nm < pore size < 50 nm) in which capillary condensation may occur. The highest compressive strength of the geopolymers was 16.57 MPa, and the desired mesoporous characteristics were met by adding 20% slag content to fly ash and adopting the hydrothermal process at a relatively low temperature. The highest BET surface area and single point adsorption pore volume of the mesoporous geopolymers were 114.16 m2/g and 0.2677 cm3/g, respectively.
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Effect of catalyst loading on hydrogen storage capacity of ZIF-8/graphene
           oxide doped with Pt or Pd via spillover
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Hu Zhou, Jian Zhang, Dong Ji, Aihua Yuan, Xiaoping Shen
      In this work, a series of zeolitic imidazolate framework (ZIF-8)/graphene oxide (GO) supported Pt or Pd nanoparticles (NPs) with different loading amounts were obtained via a simple liquid impregnation of ZIF-8/GO with metal salt solution followed by a reduction treatment. Powder X-ray diffraction, Fourier transform infrared spectra, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-emission spectroscopy, and nitrogen adsorption-desorption measurements were employed to investigate the physical and chemical properties of as-prepared samples. The Pt and Pd particles in the corresponding composites have average diameters of about 4.5 and 4.6 nm, respectively. All metal-doped ZIF-8/GO composites maintained the host framework of pure ZIF-8, although their specific surface areas were significantly reduced. The introduction of metal catalysts into the ZIF-8/GO matrix does not favor the hydrogen adsorption performance at 77 K due to the physisorption mechanism. In contrast, the adsorption isotherms at 298 exhibited dramatically improved storage capacities, by factors of 3.8–11.8 (Pt-doped ZIF-8/GO) and 7.9–12.6 (Pd-doped ZIF-8/GO) times over pristine ZIF-8 at the hydrogen pressure of 860 mmHg. This enhancement is mainly attributed to the spillover mechanism by metal catalysts into the ZIF-8/GO support. More importantly, the effect of catalysts dispersion and content on the level of hydrogen storage was also explored, which showed that the composites with the most homogeneous metal distribution and moderate loading amount would display the highest hydrogen adsorption performance.
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      PubDate: 2016-04-24T02:05:32Z
       
  • Radiofrequency controlled release from mesoporous silica nano-carriers
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Marek Šoltys, Pavel Kovačík, Miloslav Lhotka, Pavel Ulbrich, Aleš Zadražil, František Štěpánek
      Composite porous silica-iron oxide nanoparticles with the ability to store chemical payloads and release them upon triggering a radiofrequency field were prepared. The particle structure consisted of a hollow porous silica core, covered with a layer of iron oxide nanoparticles bound to the silica surface by electrostatic forces. The particle size distribution, morphology, porosity and stability was systematically studied together with their sorption capacity and heating properties under the effect of a radiofrequency magnetic field. It was observed that the particles are able to achieve a heat dissipation rate of nearly 200 W/g, which was high enough for using the radiofrequency field as a trigger mechanism for the remote release (desorption) of a chemical payload from the particles.
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      PubDate: 2016-04-24T02:05:32Z
       
  • Carbon dioxide capture with amino-functionalised zeolite-β: A
           temperature programmed desorption study under dry and humid conditions
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): David Madden, Teresa Curtin
      Novel functionalised adsorbents have been synthesised by the immobilization of aminopropyltriethoxysilane (APTES) on zeolite β. APTES modified β-25 zeolite was shown to have excellent CO2 adsorption/desorption properties, with a CO2 adsorption capacity of up to 207 mg CO2 g−1 and desorption occurring from 60 °C. The APTES modified zeolite-β most likely adsorbs CO2 via both carbamate and bicarbonate mechanisms with desorption of CO2 from the bicarbonate species occurring at a lower regeneration temperature compared to CO2 release from anhydrous carbamates. The silicon anchoring group in APTES was found to be an important characteristic in support modification with APTES molecules forming stable covalent bonds on the surface of the support which was not always observed in non-silane molecules such as tetraethylenepentamine (TEPA) particularly regarding stable bond formation on the external surface. The use of zeolite β was found to be a good support for functional amines as well as being an inexpensive starting material for the synthesis of CO2 adsorbents. The APTES modified zeolite β was found to be highly adsorbent compared with amine modified zeolites reported in literature. The adsorption capacity was maintained over a wide range of adsorption conditions and was found to be stable with repeated CO2 adsorption/desorption cycles for the APTES modified β-25 zeolite materials. The addition of moisture to the gas adsorption stream was found to further improve the CO2 adsorption capacity of the APTES modified zeolite β.
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Disordered mesoporous KIT-1 synthesized by DABCO-based ionic liquid and
           its characterization
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Haleh Sanaeishoar, Maryam Sabbaghan, Fouad Mohave, Roya Nazarpour
      The disordered mesoporous material, KIT-1, has been successfully synthesized in a facile route in the presence of mixtures of cteyltrimethylammonium bromide (CTAB) and dodcyl-4-aza-1-azaniabicyclo[2.2.2]octane bromide ([C12dabco]Br) ionic liquid as dual template for the first time. KIT-1 was characterized via FT-IR, XRD, N2 adsorption-desorption analysis, SEM and high-resolution TEM. The synthesized KIT-1 showed total BET surface area of 1012 m2 g-1, it shows slight decrease comparing to MCM-41 with BET surface area of 1029 m2 g-1. The XRD pattern of KIT-1 shows that all the diffractions are weakened and broadened compare to MCM-41. The TEM image of KIT-1 exhibits that the pore structure is a disordered network of short wormlike pores of mesopores and interconnecting to each other in a three-dimensional disordered way with relatively uniform pore size. A possible mechanism was proposed to explain the effect of ionic liquid in formation of KIT-1 sample.
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Incorporation of Ni into HZSM-5 zeolites: Effects of zeolite morphology
           and incorporation procedure
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Yadolah Ganjkhanlou, Elena Groppo, Silvia Bordiga, Mariia A. Volkova, Gloria Berlier
      Insertion of Ni species into H-ZSM5 catalysts with high Si/Al ratio (around 50) and different morphology (micron sized particles vs nanosheet ones) has been carried out by two different methods, namely impregnation and ion exchange routes. The resultant samples have been characterized by IR spectroscopy using CO as probe molecule after thermal treatment in oxygen or vacuum. In all samples different Ni2+ surface sites (counterions, grafted or on the surface of NiO particles) have been observed, but their distribution and concentration were found to be greatly influenced by morphology of zeolite particles as well as Ni incorporation method. For instance, the nanosheet morphology was found to favour ion exchange, probably in relation to high amount of surface tetrahedral Al sites. Moreover, a small fraction of sites was found to be reduced, both to Ni+ counterions and Ni0 (nano) particles, when the activation was carried out in vacuum in some of the samples. This could be related to changes in the population of surface OH groups (Brønsted sites and hydrogen bonded silanols), and to the formation of surface defects (strained SiOSi bridges). These observations give indications about the mechanism governing ion reactivity and migration in zeolite matrices, and confirm the fact that silanol groups are of the utmost importance in affecting the dispersion of the metal phase, and therefore the corresponding redox properties.
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Dative and covalent-dative postsynthetic modification of a two-fold
           interpenetration pillared-layer MOF for heterogeneous catalysis: A
           comparison of catalytic activities and reusability
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Zahra Saedi, Vahid Safarifard, Ali Morsali
      Two MOF-supported Mo(VI) oxidation catalysts bearing N,O-chelating ligand were synthesized via dative and covalent-dative postsynthetic modifications of a two-fold interpenetration pillared-layer amine-functionalized MOF known as TMU-16-NH2. These post-functionalized catalysts were characterized by FT-IR spectroscopy, thermogravimetric analysis, ICP and X-ray powder diffraction techniques. The Mo(VI)-containing MOFs exhibit both epoxide selectivity and fully reusability for alkenes epoxidation by tert-butylhydroperoxide (TBHP).
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Zinc ferrites hosted in activated carbon from waste precursors as
           catalysts in methanol decomposition
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Tanya Tsoncheva, Alexandra Mileva, Daniela Paneva, Daniela Kovacheva, Ivanka Spassova, Diana Nihtianova, Pavel Markov, Nartzislav Petrov, Ivan Mitov
      Activated carbons from peach stones and waste polyolefin wax were prepared and tested as a host matrix of nanodispersed zinc ferrite. Nitrogen physisorption, Boehm method, XRD, TPR with hydrogen, FTIR, UV–Vis and Moessbauer spectroscopy were applied to investigate the activated carbon characteristics and the state of loaded on it metal oxide particles. The higher microporosity and lower surface functionality, typical of activated carbon from waste biomass, facilitated the formation of more finely dispersed, located into the micropores iron and zinc oxide nanoparticles. This promoted formation of Zn rich ferrite phase which ensures high catalytic activity in methanol decomposition.
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Increasing mesoporosity by a silica hard template in a covalent organic
           polymer for enhanced amine loading and CO2 capture capacity
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): HaYeon Lee, Cafer T. Yavuz
      Solid sorbents for chemisorptive carbon dioxide uptake in post-combustion scenarios require strong binding groups like amines. Post-synthetic impregnation of reactive amines requires large pore volumes. Covalent organic polymers (COPs) are microporous (or narrow mesoporosity) network polymers with physisorptive behavior. Herein as the first of such attempt in porous organic polymers, we modified COP-1, which is an inexpensive, scalable porous polymer for effective amine loading. By expanding the pore of COP-1 through hard templation by silica, the surface area and pore volume are increased by 2.3 and 2.9 times, respectively. It was shown that the increase of pore volume was mostly from pores larger than 5 nm and it correlates well with the silica particle size (12 nm) and the inter-particle pore sizes of silica (31 nm). As a result, amine impregnated Si-COP-1 adsorbs CO2 with the increase of 2.44 at 273 K and 4.06 times at 298 K (at flue gas relevant partial pressure of 0.15 bar) over the parent COP-1. Our results show the possibility of tuning porosity for developing industrially feasible CO2 capturing sorbents.
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Controlled release of alendronate from nitrogen-doped mesoporous carbon
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Dipendu Saha, Amanda Spurri, Jihua Chen, Dale K. Hensley
      We have synthesized a nitrogen doped mesoporous carbon with the BET surface area of 1066 m2/g, total pore volume 0.6 cm3/g and nitrogen content of 0.5%. Total alendronate adsorption in this carbon was ∼5%. The release experiments were designed in four different media with sequential pH values of 1.2, 4.5, 6.8 and 7.4 for 3, 1, 3 and 5 h, respectively and at 37 °C to imitate the physiological conditions of stomach, duodenum, small intestine and colon, respectively. Release of the drug demonstrated a controlled fashion; only 20% of the drug was released in the media with pH = 1.2, whereas 64% of the drug was released in pH = 7.4. This is in contrary to pure alendronate that was completely dissolved within 30 min in the first release media (pH = 1.2) only. The relatively larger uptake of alendronate in this carbon and its sustained fashion of release can be attributed to the hydrogen bonding between the drug and the nitrogen functionalities on carbon surface. Based on this result, it can be inferred that this formulation may lower the side effects of oral delivery of alendronate.
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Well-dispersed gold nanoparticles anchored into thiol-functionalized
           hierarchically porous materials for catalytic applications
    • Abstract: Publication date: 15 July 2016
      Source:Microporous and Mesoporous Materials, Volume 229
      Author(s): Yang Xu, Tianqi Wang, Zidong He, Aiqing Zhong, Kun Huang
      In this work, we demonstrate a novel method that enables the fabrication of thiol-functionalized hierarchically porous materials (SH-HPMs) by combination of hyper-cross-linking and molecular templating of core-shell bottlebrush copolymers. Well-dispersed gold (Au) nanoparticles with an average size of 3.0 nm, synthesized by in situ reduction of HAuCl4, were then anchored into the SH-HPMs support, which showed remarkable catalytic performances on the reduction reaction of 4-nitrophenol.
      Graphical abstract image

      PubDate: 2016-04-24T02:05:32Z
       
  • Equilibrium and kinetic studies for adsorption of iron from aqueous
           solution by synthetic Na-A zeolites: Statistical modeling and optimization
           
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Moaaz K. Seliem, Sridhar Komarneni
      In this study, two different methods were used in the synthesis of Na-A zeolites from kaolinite collected from Aswan area, Egypt: (I) kaolinite was fused with sodium hydroxide prior to hydrothermal treatment to prepare Na-A zeolite (ZAF) and (II) kaolinite was subjected to calcination followed by reaction with alkaline solution to synthesize Na-A zeolite (ZAC). The synthetic Na-A zeolites were characterized by XRD and SEM; surface area was measured using N2 adsorption and the BET equation. The behavior of each synthetic zeolite for iron uptake was evaluated by studying the influence of different experimental parameters such as contact time, initial iron concentration and zeolite mass. Optimization of iron uptake by the synthetic Na-A zeolites was performed using a central composite rotatable design (CCRD) under response surface methodology (RSM). The results showed that the maximum removed amounts of iron by ZAF (5.62 mg/g) was obtained after 5 min of contact time while the highest amount of iron by ZAC (4.3 mg/g) was given after 8 h. By increasing the adsorbent mass from 0.4 g to 0.6 g, the removal efficiency of iron onto the synthetic zeolites increased from 45% to 87.6% for ZAF and from 35% to 86.7% for ZAC. The adsorption process fitted the Langmuir model and the adsorption kinetics correlated very well with the pseudo-second-order equation. Based on the predicted optimized solutions for iron adsorption, the removal efficiency of iron could be enhanced in both of ZAF and ZAC.
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      PubDate: 2016-04-19T10:03:23Z
       
  • Impact of plasma reactive ion etching on low dielectric constant porous
           organosilicate films' microstructure and chemical composition
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Matthieu Lépinay, Daniel Lee, Riccardo Scarazzini, Michel Bardet, Marc Veillerot, Lucile Broussous, Christophe Licitra, Vincent Jousseaume, François Bertin, Vincent Rouessac, André Ayral
      The impact of plasma reactive ion etching on hybrid organic/inorganic polymer materials is investigated in detail regarding chemical (composition) and physical (porosity) aspects. Porous low dielectric constant insulating films are used in integrated circuits and these experience plasma etching before the deposition of conductive copper lines. We show that this induces detrimental changes in the film. Notably, chemical composition modifications were characterized by Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and depth-profiled by Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), whereas fine structural changes were analyzed with 1H, 13C, and 29Si solid-state Nuclear Magnetic Resonance (ssNMR). Evolution of surface properties was measured with Contact Angle (CA) analysis, while porosity variations were probed with Ellipsometric Porosimetry (EP). We show how the complementarity of these techniques enables a thorough description of the impact of the etching process on this low-dielectric constant material, which in turn enables recommendations for the manufacture of microelectronic devices.
      Graphical abstract image

      PubDate: 2016-04-19T10:03:23Z
       
  • Synthesis and characterization of NiO/ MgAl2O4 nanocrystals with high
           surface area by modified sol-gel method
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): M. Boroujerdnia, A. Obeydavi
      In this work, NiO/MgAl2O4 nanocrystals were prepared by modified sol–gel method and the effects of molar ratio of diethylene glycol monoethyl ether (DGME) to citric acid (2, 4, 7) and the content of nickel (5, 10, 12, 15 and 20 Wt.%) were investigated on the structural properties of nanocrystals. The prepared powders were characterized by XRD, FTIR, TGA-DSC, FESEM with the energy dispersive X-ray spectroscopy (EDX), TEM and BET. The results obtained by X-ray and BET showed that NiO/MgAl2O4 nanocrystals prepared by the modified sol-gel method have small crystal size, meso-pore structure with a high specific surface area in different amounts of nickel. The specific surface area of NiO/MgAl2O4 nanocrystals was reduced from 147 m2 g−1 to 118.4 m2 g−1 as the content of Ni increased from 5 to 20 wt %. It was observed that in the molar ratios of DGME: CA: 4, the smallest size of crystalline NiO and MgAl2O4 phase was estimated about 12.5 nm and 13.5 nm, respectively. Also, The results from FESEM showed that the morphology of surface NiO/MgAl2O4 powders with 20 wt %Ni in molar ratios of DGME: CA: 2, 4 and 7 were spherical, cubic and sponge, respectively. Furthermore, the results from TEM showed that NiO/MgAl2O4 powders with 15 wt %Ni and in molar ratios of DGME: CA: 4 had nanometric particles about 10 nm, polycrystalline and mesopores structure.
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      PubDate: 2016-04-19T10:03:23Z
       
  • Rhodamine 6G loaded zeolitic imidazolate framework-8 (ZIF-8)
           nanocomposites for highly selective luminescent sensing of Fe3+, Cr6+ and
           aniline
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Ting-Ting Han, Jin Yang, Ying-Ying Liu, Jian-Fang Ma
      Fluorescence-based probes exhibit apparent superiority in high sensitivity, selectivity and easy operation. As a typical representative of zeolitic imidazolate frameworks (ZIFs), highly porous ZIF-8 has attracted intense interests because of its potential applications. In this work, the organic dye Rhodamine 6G (R6G) loaded ZIF-8 nanocomposites were prepared and well characterized by transmission electron microscope (TEM), powder X-ray diffraction (PXRD) and N2 adsorption. The R6G loaded ZIF-8 (R6G@ZIF-8) nanocomposites exhibit intense luminescence with wide wavelength band in the visible light region. The luminescent detections of metal ions, anions, organic small molecules and polyoxometalates were fully studied using the as-synthesized R6G@ZIF-8 nanocomposites as sensory materials. Strikingly, the luminescent detections indicate that R6G@ZIF-8 nanocomposites are capable of highly selective sensing of Fe3+, highly toxic Cr 6+ and organic aniline with a low detection limit of 5 μM, 50 μM and 5 mM, respectively. More significantly, luminescence quenching and recovery tests demonstrate that R6G@ZIF-8 nanomaterials are reusable for the detections of Fe3+, Cr 6+ and organic aniline.
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      PubDate: 2016-04-19T10:03:23Z
       
  • Antiphlogistic effect by zeolite as determined by a murine inflammation
           model
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Javiera Cervini-Silva, Antonio Nieto-Camacho, Stephan Kaufhold, Kristian Ufer, Eduardo Palacios, Ascención Montoya, Wilfried Dathe
      Natural zeolites are microporous crystalline aluminosilicates with channels and cavities of molecular dimensions of interest for biomedical applications. The antiphlogistic effect was investigated on the basis of a murine inflammation model using 12-O-tetradecanoylphorbol-13-acetate (TPA) as inflammatory agent and the quantification of the activity of myeloperoxidase (MPO), an enzyme that serves as an indicator for neutrophil migration. The zeolite used in this study was collected from San Andrés, Cuba, and it provided evidence to show the quantitative adsorption of histamine, a biogenic compound strongly involved in inflammation processes. Furthermore, a related work showed that this zeolite sample is free of hazardous materials and apt for health use. The zeolite of this study contained 65% clinoptilolite, 30% mordenite, and 5% smectite. The application of this zeolite reduced the edema formation induced by TPA within 24 h by 57.2 ± 18%, while the migration of neutrophils was not altered. The anti-inflammatory activity of zeolite was explained in part due to the quantitative adsorption of histamine, whilst natural cell repair mechanisms appeared not to be influenced. The outcome of this work expanded on reports concluding that antiphlogistic properties of zeolite proven in vivo with mice for inflammatory diseases are important for both oral application (gastrointestinal tract) and topical treatment (skin), too.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • A new method for the generation of realistic atomistic models of siliceous
           MCM-41
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Christopher D. Williams, Karl P. Travis, Neil A. Burton, John H. Harding
      A new method is outlined for constructing realistic models of the mesoporous amorphous silica adsorbent, MCM-41. The procedure uses the melt-quench molecular dynamics technique. Previous methods are either computationally expensive or overly simplified, missing key details necessary for agreement with experimental data. Our approach enables a whole family of models spanning a range of pore widths and wall thicknesses to be efficiently developed and yet sophisticated enough to allow functionalisation of the surface – necessary for modelling systems such as self-assembled monolayers on mesoporous supports (SAMMS), used in nuclear effluent clean-up. The models were validated in two ways. The first method involved the construction of adsorption isotherms from grand canonical Monte Carlo simulations, which were in line with experimental data. The second method involved computing isosteric heats at zero coverage and Henry law coefficients for small adsorbate molecules. The values obtained for carbon dioxide gave good agreement with experimental values. We use the new method to explore the effect of increasing the preparation quench rate, pore diameter and wall thickness on low pressure adsorption. Our results show that tailoring a material to have a narrow pore diameter can enhance the physisorption of gas species to MCM-41 at low pressure.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • Preparation of a graphitic ordered mesoporous carbon and its application
           in sorption of ciprofloxacin: Kinetics, isotherm, adsorption mechanisms
           studies
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Xiaoming Peng, Fengping Hu, Jiale Huang, Yajun Wang, Hongling Dai, Zhanmeng Liu
      A graphitic ordered mesoporous carbon (OMC) was fabricated by a nanocasting process by using silica SBA-15 as a template and pitch resin as carbon precursor. The modification and application of the OMC for Ciprofloxacin (CIP) removal from the aqueous solution were investigated. The results exhibited that the OMC modified with different chemical agent were more efficient than the unmodified one. The CIP adsorption increased with the increase of their neutral (CIP0) or zwitterionic (CIP±) formed on the adsorbents because of hydrophobic effect. The adsorption amount of CIP onto the adsorbents increased with NaCl concentration. The data was analyzed by the Langmuir, Freundlich and Temkin isotherms. The results indicated that adsorption of CIP onto the four adsorbents fitted better with the Langmuir model. The adsorption process follows pseudo second-order kinetic model. The results of the present study suggested that the original and modified OMC were effective sorbents for removal of antibiotics from aqueous solutions.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • Role of cation size for hydrogen carbonate stabilization and modification
           of the zeolite–CO2 interaction energy: Computational analysis in
           alkali Y zeolites
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): A.V. Larin
      The energies of CO2 interaction with MeY zeolites containing different alkali cations (Me = Li, Na, K, Cs) at small coverage of MeY zeolites are studied using DFT modeling (PBE, PBE-D2, optPBE-vdW, optB88-vdW, and optB86b-vdW functionals). The role of CO2 interaction with HCO3 − is analyzed to explain unusual decreasing order of the heats of CO2 adsorption in the sequence CsY > KY > NaY > LiY recently observed. The largest isosteric heat of adsorption in CsY is assigned to the interactions with HCO3 − whose maximum concentration in CsY was confirmed via IR tools.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • Experimental and theoretical study of quercetin complexes formed on pure
           silica and Zn-modified mesoporous MCM-41 and SBA-16 materials
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Margarita Popova, Ivalina Trendafilova, Ágnes Szegedi, Judith Mihály, Péter Németh, Sylvia G. Marinova, Hristiyan A. Aleksandrov, Georgi N. Vayssilov
      SBA-16 and MCM-41 silica materials were synthesized and modified by post-synthesis method with different amounts of Zn (2 and 4 wt.%). Quercetin, a flavonol compound, was loaded by incipient wetness impregnation method on the pure silica and Zn-modified mesoporous MCM-41 and SBA-16 supports. The parent and drug loaded formulations were characterized by powder XRD, N2 physisorption, thermal analysis, TEM, UV Vis and FT-IR spectroscopies. The formation of Zn:quercetin complex was studied by FT-IR spectroscopy and quantum-chemical calculations. Loading of quercetin on mesoporous carriers made the sustained delivery of the bioactive compound possible in a buffer with pH = 5.5, typical of dermal formulations. The results from the release experiments are in good accordance with the interaction energy between the bioactive molecule and non-modified and Zn-modified mesoporous materials, predicted by the quantum-chemical calculations. For the first time the formation of the most stable Zn quercetin complexes loaded on the mesoporous silica materials were determined. The obtained mesoporous delivery systems with Zn-quercetin complex are promising as dermal formulations.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • A novel hyper-cross-linked polymeric adsorbent with high microporous
           surface area and its adsorption to theophylline from aqueous solution
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Guqing Xiao, Ruiming Wen, Dongmei Wei, Dan Wu
      According to the planar structure and the small molecular size of theophylline (TP), a novel hyper-cross-linked polymeric adsorbent with high microporous surface area (denoted GQ-06) was synthesized and its adsorption to TP was explored from aqueous solution. The results showed that GQ-06 possessed a high microporous surface area of 1223 m2/g and bimodal pore size distributions. The equilibrium adsorption capacity of TP on the five polymeric adsorbents followed an order as: XAD-4 < NDA-88 < H103 <NDA-150 <GQ-06, which was in agreement with the order of the microporous surface area. The adsorption as a function of the solution pH was accordant with the dissociation curve of TP from aqueous solution. The equilibrium adsorption capacity of TP on GQ-06 increased with increasing of the ionic strength due to the predominant contribution of the hydrophobic effect. The pseudo-first-order rate equation described the adsorption in two stages according to the bimodal pore size distributions. The adsorption isotherms were correlated to the Freundlich equation. The breakthrough capacity and the total capacity of TP on GQ-06 were up to 45.9 and 105.8 mg/mL respectively, and it could be regenerated by 4 BV of anhydrous ethanol.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • Evidence for the formation of stable CO2 hydrates in zeolite NaY:
           Structural characterization by synchrotron X-ray powder diffraction
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Rossella Arletti, Lara Gigli, Francesco di Renzo, Simona Quartieri
      Preferential adsorption of water is a major problem in the processes of CO2 adsorption on molecular sieves. Adsorption and desorption of CO2 on partially hydrated zeolite NaY have been monitored by in situ synchrotron X-ray powder diffraction. The structural refinement of the CO2-saturated diffraction pattern highlighted the formation of tetrameric CO2 clusters connected by water bridges to the sodium cations of two adjacent faujasite supercages. The CO2 desorption was followed by collecting a series of diffraction patterns upon heating from room temperature up to 350 °C. The hydrated CO2 clusters are completely desorbed between 250 °C and 350 °C. This high thermal stability suggests that the formation of hydrated complexes could represent a potentially important mechanism of retention of CO2 during the regeneration of CO2 adsorbents.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • Preparation of Y zeolite composites with adjustable, highly dispersed
           intra-crystal mesoporosity: Effect of lactic acid treatment in
           CTAB-assisted two-step approach
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Wen Qian Jiao, Jian Ding, Zong Bo Shi, Xiao Min Liang, Yi Meng Wang, Ya Hong Zhang, Yi Tang, Ming-Yuan He
      Series of meso/microporous zeolite Y composites with adjustable hierarchy factors (HF) from 0.04 to 0.16, are prepared from commercial NaY zeolite (Si/Al = 2.5) by the two-step method with first lactic acid leaching and then CTAB-assisted ammonia treatment. The essential effect of lactic acid on the formation of diverse mesoporous domains in microporous crystals are systematically investigated. A possible scheme is proposed. The lactic acid leaching process is found to be very crucial to controllably remove the framework aluminum and regulate the amount/size of intra-crystal amorphous silicon-rich domains, which then evolve to mesostructures within the microporous crystals via structural re-arrangement/dissolution-reassembly process during the CTAB-assisted ammonia treatment. Varying the lactic acid concentrations would result in different crystallinity preservations and diverse proportions/dispersity of mesoporous regions, and thus well tune the HF values of the final composites. The zeolite Y composites with moderate mesoporosities allow much better performances in the acetalization reactions of cyclohexanone with pentaerythritol due to the improved diffusion ability of large sized guest molecules, whereas accompanying loss of acidity would depress reactivities of the treated samples for dehydration of small isopropanol.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • Indolo[3,2-b]carbazole-containing hypercrosslinked microporous polymer
           networks for gas storage and separation
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Dan Chang, Miao Yu, Chong Zhang, Yang Zhao, Rui Kong, Fangyuan Xie, Jia-Xing Jiang
      Two indolo[3,2-b]carbazole-containing hypercrosslinked microporous organic polymers have been successfully synthesized via Friedel-Crafts alkylation reaction in the presence of anhydrous FeCl3. It was found that the polymer InCz-HCP2 produced from the monomer with more reaction active sites shows a higher Brunauer-Emmet-Teller specific surface area up to 1421 m2 g−1 than InCz-HCP1. Both polymers show high isosteric heats of CO2 adsorption over 27 kJ mol−1 because the incorporation of indolo[3,2-b]carbazole unit into the skeleton of the polymers enhanced the binding affinity between the pore wall of the polymer and CO2 molecules. InCz-HCP2 shows a hydrogen uptake ability of 1.68 wt% (77.3 K/1.13 bar) and a carbon dioxide capture capacity of 3.58 mmol g−1 at 273 K/1.13 bar with a good CO2/N2 selectivity of 29:1 at 273 K. With those adsorption properties, these materials could be considered as potential candidates for gas storage and separation.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • Synthesis of Ag-loaded 4A-zeolite composite catalyst via supercritical CO2
           fluid for styrene epoxidation
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Xiaosong Hu, Jie Bai, Hailong Hong, Chunping Li
      In this paper, the silver nanoparticles (Ag NPs) were uniformly distributed to the 4A-zeolite via supercritical carbon dioxide (scCO2), and polyvinylpyrrolidone (PVP) was used as the capping agents. The transmission electron microscopy (TEM) detection of composite catalyst displayed that the Ag NPs had a narrow size distribution (3–6 nm). Catalytic property evaluation resulting showed the excellent catalytic activity of the Ag NPs/4A-zeolite samples. The high conversion of styrene and the superior selectivity of styrene oxide (SO) were shown to us when tert-butyl hydroperoxide (TBHP) was used as the oxidant in short reaction time. Solvents effects played a important role in the reaction, and acetonitrile was the optimal solvent for the styrene epoxidation via the investigation of solvents.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • Interaction mechanism of Ni(NO3)2·6H2O and P123 in preparing
           highly-dispersed Ni/SBA-15 catalytic materials
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Weiwei Yang, Huimin Liu, Yuming Li, Dehua He
      P123 (PEG-PPG-PEG triblock copolymer) was employed as a modifying agent to prepare highly-dispersed Ni/SBA-15 via a simple wetness impregnation method. A detailed molecular-level pathway had been illuminated to interpret the role of P123 during the catalyst preparation process with Raman, 1H-NMR, UV–Vis, DLS, FTIR, and TPO measurements. There existed no interaction between Ni(NO3)2·6H2O and P123 during impregnation and evaporation steps with the existence of H2O in the media. The oxygen atoms of PEO blocks would coordinate with Ni2+, NO3 − and H2O to form crown-ether-type complexes when the water was evaporated out from the solution during the drying step, which improved the dispersion and stabilization of the precursor. And the complexes ultimately inhibited the redistribution and affected the decomposition of Ni(NO3)2·6H2O precursor during calcination. All in all, the above specific interaction between Ni(NO3)2·6H2O and P123 would lead to a critical influence of P123 addition on the NiO dispersion on the support.
      Graphical abstract image

      PubDate: 2016-04-14T09:59:18Z
       
  • AlPO4-5 zeolite at high pressure: Crystal–fluid interaction and
           elastic behavior
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Paolo Lotti, G. Diego Gatta, Davide Comboni, Marco Merlini, Linda Pastero, Michael Hanfland
      The high-pressure behavior of the aluminophosphate zeolite AlPO4-5 (AFI-topology) has been investigated by in situ single-crystal synchrotron X-ray diffraction with a diamond anvil cell, using the “non-penetrating” silicone oil and the “penetrating” 16:3:1 methanol:ethanol:water (m.e.w.) mixture as P-transmitting fluids. The crystals used in this study showed diffraction patterns typical of an incommensurate modulated structure, with modulation vector q ≈ 0.37c*. Compression in silicone oil showed that AlPO4-5 is one of the softest zeolites reported so far, being its refined bulk modulus (K V0 = 1/β V ) at ambient conditions only 13.2(11) GPa (β V  = 0.076(6) GPa−1), with an elastic anisotropy K a :K c  = 1.6. The high-pressure experiment performed using m.e.w. showed a significantly lower compressibility of AlPO4-5, if compared to the behavior in silicone oil, suggesting the occurrence of a P-induced intrusion of the fluid molecules into the zeolitic cavities. An indirect evidence for the molecules intrusion is provided by the comparative analysis of the structure deformation mechanisms at the atomic scale. When zeolite AlPO4-5 is compressed in m.e.w., a lower degree of distortion of the secondary building units is observed, with respect to the compression in silicone oil. Overall, this study suggests zeolite AlPO4-5 as a promising microporous material for the pressure-mediated intrusion and hyper-confinement of molecules into the structural micropores.
      Graphical abstract image

      PubDate: 2016-04-09T13:22:14Z
       
  • A metal dicyanamide cluster with high CO2/N2 selectivity
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Aysun Tekin, Ozan Karalti, Ferdi Karadas
      A new microporous metal dicyanamide cluster, Co(hmt)(dca)2 (hmt: hexamethylenetetramine, dca: dicyanamide), with accessible N-donor sites exhibits high CO2/N2 selectivity, 83 at 295 K and 1 bar, for a mixture with a 15:85 CO2 to N2 ratio. Adsorption studies show that the use of hmt and dca moieties as building blocks for solid adsorbents can enhance the CO2:surface interactions due to N atoms available inside the pores, which is confirmed by X-ray single crystal studies.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • Influence of crystal size on the uptake rate of isooctane in plain and
           hollow silicalite-1 crystals
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): N. Novruzova, A. Tuel, D. Farrusseng, F.C. Meunier
      The sorption kinetics of isooctane at 150 °C over a series of silicalite-1 materials comprising small and large crystals and their corresponding hollow forms were followed by in situ diffuse reflectance FT-IR spectroscopy. The results suggest that sorption rate was mostly limited by surface effects in the case of small (i.e. 100 nm diameter) crystals, while this was not the case for much larger crystals.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • Crystallization and assembling of FAU nanozeolites on porous ceramic
           supports for zeolite membrane synthesis
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Teresa F. Mastropietro, Enrico Drioli, Sebastiano Candamano, Teresa Poerio
      In this study, a novel route for preparing nanocrystalline porous FAU layers s stably supported on porous α-Al2O3 tubular substrates is reported. A highly reactive sodium hydroxide rich hydrogel was used to promote the nucleation process on the support surface. After 24 h of treatment at near ambient condition, a heavily nucleated quasi-solid gel layer containing nanozeolite precursor species was first formed on the support surface. This matrix was used as starting material for the synthesis of nanozeolite-based membranes. The support coated with the extensively nucleated gel phase was isolated and cured at higher temperature in different conditions. A rapid and diffuse crystallization was observed by treating the gel matrix with a synthesis solution of lower alkalinity, leading to the formation of a dense nanocrystalline FAU layer firmly adhered to the substrate surface. The FAU layers (Si/Al ratio of ca. 2) have a thickness of ca. 2 μm and are constituted by closely packed, well intergrown nanocrystals (crystallite dimension of ca. 20–30 nm). The results of this study indicate that supersaturation as well as the elevate amount of sodium ions synergistically contribute to induce the assembling of soluble aluminosilicate species on the support surface and to effectively promote the heterogeneous nucleation process.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • Polystyrene-silica aerogel nanocomposites by in situ simultaneous reverse
           and normal initiation technique for ATRP
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Khezrollah Khezri, Hossein Mahdavi
      Hexamethyldisilazane (HMDS) was employed to surface modification of hydrophilic silica aerogel nanoparticles. Then, the resultant modified nanoparticles were used for in situ polymerization of styrene by simultaneous reverse and normal initiation technique for atom transfer radical polymerization (SR&NI ATRP) to synthesize tailor-made polystyrene nanocomposites. Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) were employed for demonstrating success surface modification of hydrophilic silica aerogel nanoparticles with HMDS. Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the synthesized hydrophobic silica aerogel nanoparticles. Evaluation of size distribution and morphological studies were also performed by SEM and TEM. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography respectively. Addition of 3 wt% hydrophobic silica aerogel nanoparticles results in a decrease of conversion from 97 to 77%. Molecular weight of polystyrene chains decreases from 11095 to 8755 g.mol-1 by addition of 3 wt% hydrophobic silica aerogel nanoparticles; however, polydispersity index (PDI) values increases from 1.15 to 1.46. Appropriate agreement between theoretical and experimental molecular weight in combination with low PDI values demonstrate the living nature of the polymerization. Thermal stability of the neat polystyrene and its different nanocomposites are studied by TGA. Differential scanning calorimetry shows a decrease in glass transition temperature from 94.8 to 83.5 °C by adding 3 wt% of hydrophobic silica aerogel nanoparticles.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • A novel approach to adsorption kinetics calculation
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Miroslav Kukučka, Nikoleta Kukučka, Andrej Kukučka
      A new model for synthetic zeolite adsorption kinetics calculation was developed. Investigations were carried out using dynamic fixed-bed pilot plant on natural groundwater with ammonia concentration of 2.24 mgNH4 +-N/L. The new approach for computing the pseudo-equilibrium adsorption capacity of zeolite toward ammonia was applied and specific adsorption rate was theoretically defined and empirically putted to use. Three-stage adsorption kinetic process was cognized on the base of experimental data. The first stage characterized slow decrease and then slow rise of effluent ammonia concentrations until 20 h of experimental time and 200 BV. Subsequently, fast ammonia increase across the breakthrough point comprised the second stage. After 530 BV and 50 h of overall experimental time slow rise of effluent concentrations toward the inlet ammonia concentration value was observed until 96.5 h and 1017 BV and characterized as the third stage. Applied pseudo-first and pseudo-second kinetic modeling showed that all experiments data can be explained by the pseudo-first kinetic model with Qe = 112.31 mgNH4 +-N/g and k1 = 0.068 h−1 while the third stage better fits to the pseudo-second model where obtained values for Qe and k2 were 125 mgNH4 +-N/g and 7.5·10−4 g mgNH4 +-N−1 h−1, respectively. It was found that investigated adsorption process was non-equilibrium in all stages with the exception of the final part of the third stage. Pseudo-equilibrium occurred at the end of the third stage with adsorption capacity of 109.60 mgNH4 +-N/g.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • A novel synthetic route to obtain RUB-15 phase by pseudo solid-state
           conversion
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Fethi Kooli, Yan Liu, Kais Hbaieb, Rawan Al-Faze
      The conventional method of zeolite synthesis consists of the hydrothermal treatment of a mixture of a silica source, structure-directing agent, water, and/or organic solvent. In this study, a simple physical mixture of a layered silicate (protonated magadiite) and solid tetramethylammonium pentahydrate (TMAOH.5H2O) was treated in a Teflon-lined autoclave at 150 °C–170 °C for different periods of time. The protonated magadiite was completely transformed to RUB-15 after three days at 170 °C, the shortest time ever reported for this type of zeolite. By increasing the reaction time to five days, a different phase than RUB-15 was obtained and identified as PLS material. The conversion of the protonated magadiite depended on the amounts of water and TMAOH.5H2O used. The addition of several drops of water to the mixture enhanced the formation of the PLS-1 phase within three days, and no RUB-15 was detected. These phases contain TMA cations in different environments, as supported by thermogravimetric analysis and 13C solid state NMR. This method minimizes the use of water and the production of waste, in addition to reducing the reaction time compared to the conventional method.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • Static in-situ hydrothermal synthesis of small pore zeolite SSZ-16 (AFX)
           using heated and pre-aged synthesis mixtures
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): P. Hrabanek, A. Zikanova, T. Supinkova, J. Drahokoupil, V. Fila, M. Lhotka, H. Dragounova, F. Laufek, L. Brabec, I. Jirka, B. Bernauer, O. Prokopova, V. Martin-Gil, M. Kocirik
      The conditions of static in-situ hydrothermal synthesis were optimized to prepare crystalline, pure phase and template-free small pore zeolite SSZ-16 (AFX) particles. The type of silica source and prolonged ageing process at an elevated temperature were decisive in obtaining pure phase zeolite SSZ-16 particles under static conditions and conventional heating. Colloidal and fumed silica-based synthesis mixtures were successful in forming the zeolite SSZ-16. The zeolite particle size was reduced from 46 to 5 μm when the fumed silica was replaced by colloidal silica. Uniform, fine-grained and fully crystalline zeolite SSZ-16 particles were synthesized only from the colloidal silica-based mixtures that were aged at 80 °C for 7 days. The elevated temperature of the ageing stage is supposed to promote nucleation of viable nuclei leading to the reduction of the induction period. The two cycle calcination procedure with maximal temperature of 550 °C, ensured the removal of template molecules from the bulk phase of zeolite SSZ-16 particles. Carbonaceous residua were observed in zeolite subsurface region and mainly in the core shell morphology of zeolite SSZ-16 particles. The phase purity of zeolite SSZ-16 particles was checked by XRD and sorption properties were determined by N2 adsorption at −196 °C. Zeolite SSZ-16 particles showed the micropore volume of 0.24 cm3/g and BET surface area of 496 m2/g.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • Complex investigation of charge storage behavior of microporous carbon
           synthesized by zeolite template
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Marija Stojmenović, Milica Vujković, Ljiljana Matović, Jugoslav Krstić, Anđelka Đukić, Vladimir Dodevski, Sanja M. Živković, Slavko Mentus
      Microporous zeolite templated carbon (ZTC) was synthesized by impregnation method using zeolite Y (Na-form) as a template, and furfuryl alcohol as a carbon precursor. The characterization was carried out by X-ray diffractometry, Raman spectroscopy, scanning electron microscopy, nitrogen physisorption, elemental analysis and electrochemical methods. Physisorption measurements evidenced high micropore volume of obtained material (∼0.43 cm3 g−1). The charge storage ability in aqueous KOH, H2SO4 and Na2SO4 solutions was systematically studied by cyclic voltammetry, galvanostatic charging/discharging and complex impedance measurements. Specific coulombic capacitance, the hydrogen storage, HZTC bonding and relaxation time of adsorption were found to be dependent on the type of electrolyte. Neutral Na2SO4 aqueous solution was found to be the best for supercapacitor application, thanks to: i) the highest available voltage window ii) lowest corrosion and iii) highest capacitance amounting to 123 F g−1 at 1 A g−1.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • Synthesis and characterization of zeolite L prepared from hydrothermal
           conversion of magadiite
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Yu Wang, Tianming Lv, Ye Ma, Fuping Tian, Li Shi, Xiaoyu Liu, Changgong Meng
      Zeolite L has been synthesized by magadiite conversion method. The crystallization behavior and changes of medium-range structure during the crystallization were investigated by X-ray diffraction, scanning electron micrograph, vibrational spectroscopy and 27Al magic angle spinning nuclear magnetic resonance. It is indicated that parts of 6 member-rings in magadiite still exist as secondary building units although the long-range order of magadiite was collapsed in the initial stage. The 4 member-rings and 8 member-rings were formed after the sample was heated for 3 h and 4 h, respectively. The influence of various parameters such as reaction temperature, time and substrate composition was examined. Highly crystallized and pure zeolite L could be prepared from the substrates with molar composition: 0.56M2O–xAl2O3 SiO2 49H2O (M2O = K2O + Na2O, x = 0.0033–0.04) by heating at 140 °C for 18 h, 160 °C for 12 h or 180 °C for 8 h.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • Understanding fluid transport through claystones from their 3D nanoscopic
           pore network
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Yang Song, C.A. Davy, P. Bertier, D. Troadec
      This paper investigates the complex and nanoscopic pore network of claystones, after their retrieval from the geological layer, and their further conditioning and drying, as it is usually done to assess their fluid permeability (i.e. their transport properties). Following the leading research of Keller et al. [1] on the Swiss Opalinus clay, and because no percolating pore network is obtained at bigger scales, we provide micrometric pore volumes for a French Toarcian claystone and for a Callovo-Oxfordian claystone [2], by Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) imaging. The voxel size ranges from 5.94 × 7.54 × 10 nm3 to 8.49 × 10.78 × 50 nm3, and the investigated volumes range between 28 and 553 μm3. Comparison with nitrogen adsorption data is proposed. One originality of our research is to prepare the samples as for the assessment of macroscopic fluid transport, by moderate drying at centimetric size. It is observed that, at the scale imaged by FIB/SEM, fluid transport occurs through very limited percolating parts of the pore network (0.7–2.1%). For both claystones, pore volumes generally percolate by sub-micrometric cracks, attributed to drying, and more seldomly by tortuous parts (not of a crack nature). Fluid transport is predicted by Katz–Thompson equation from the 3D geometry of the shortest percolating path. This provides permeability values on the order of 10−21–10−20 m2 (1–10 nD), in good agreement with experimental data. This study hints at a mechanism of fluid transport by fingering through pores as small as 20 nm diameter, rather than homogeneously through the whole claystone volume.
      Graphical abstract image

      PubDate: 2016-04-04T13:23:19Z
       
  • Microwave synthesis of zeolite CHA (chabazite) membranes with high
           pervaporation performance in absence of organic structure directing agents
           
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Na Hu, Yuqin Li, Shenglai Zhong, Bin Wang, Fei Zhang, Ting Wu, Zhen Yang, Rongfei Zhou, Xiangshu Chen
      Thin and compact zeolite chabazite membranes were prepared by microwave heating using symmetric stainless steel tubular supports. The microstructures (crystal size and membrane thickness) and separation performances of supported chabazite layers were strongly affected by heating method, synthesis time and synthesis temperature. The best membrane prepared by microwave heating under optimized conditions showed fluxes of 7.3 and 9.1 kg/(m2 h) and separation factors of 2000 and 2500 for 90 wt.% ethanol and isopropanol aqueous solutions at 348 K, respectively. These fluxes were twice as high as those of the chabazite membranes prepared by conventional heating due to the thinner zeolite layers and lower resistance of the support layer in the microwave heating system. The membrane prepared on the 3-time-reused stainless steel support showed comparable separation performance with the membrane on the fresh support, suggesting that the stainless steel supports had a good reuse prospect for chabazite membrane preparation. Synthesis reproducibility and hydrothermal stability of chabazite membranes by microwave heating were also investigated.
      Graphical abstract image

      PubDate: 2016-03-30T13:21:04Z
       
  • Mesoporous In-Sn binary oxides of crystalline framework with extended
           compositional variation
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Jangkeun Cho, Changbum Jo, Jae Won Shin, Seung Hyeon Ko, Ryong Ryoo
      Indium-tin oxide is considered a highly promising mixed-metal oxide system, because it shows good performance in various industrial processes. Therefore, it will be of great importance to explore the possibility of obtaining new In-Sn oxides with controlled contents whose properties could be tailored. However, In or Sn content in In-Sn oxides has generally been restricted to <10% because of their low solid solubility into counterpart metal oxide framework. Herein, we report for the first solvothermal synthesis of crystalline mesoporous In-Sn oxides with a broad range of In/Sn ratios and their opto-electrochemical properties. For the synthesis, we use phenolic polymer as a structure-directing agent. Surprisingly, we observe that the phenolic polymer plays a critical role in overcoming their low solubility by manipulating kinetics of crystal nucleation and subsequet growth. As a result, we obtain In-rich rutile SnO2 phase without phase separation with up to 50% In content and Sn-rich rhombohedral In2O3 structure with higher In content. The synthesized materials are highly transparent regardless of In content. The electrochemical properties are sensitive to In content. Our strategy offers possibility of realizing crystalline mesoporous mixed-metal oxides with tunable contents, thus opening a new perspective for the development of optoelectronic materials.
      Graphical abstract image

      PubDate: 2016-03-30T13:21:04Z
       
  • Self-templating synthesis of hollow spheres of zeolite ZSM-5 from
           spray-dried aluminosilicate precursor
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Veronika Pashkova, Venceslava Tokarova, Libor Brabec, Jiri Dedecek
      Synthesis of hollow spheres consisting of ZSM-5 zeolite crystals, prepared by a cost- and time-saving self-templating process, requires neither a hard/soft template for sphere formation nor tetraalkylammonium compound as a zeolite structure-directing agent. A preshaped aluminosilicate precursor, obtained by spray drying of a mixture of colloidal solution of silicic acid and aluminum butoxide, plays the role of a shape-directing agent for the formation of spheres, and is used as a source of silica and alumina for zeolite growth. The zeolite structure is directed using ZSM-5 seeds. This method yielded highly stable hollow spheres with diameters of 15–25 μm, consisting of inter-grown ZSM-5 crystals (Si/Al 14) with a size of 0.5–2.0 μm.
      Graphical abstract image

      PubDate: 2016-03-30T13:21:04Z
       
  • Ultrafast microwave synthesis of all-silica DDR zeolite
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Lu Bai, Guizhen Nan, Yihui Wang, Deng Hu, Gaofeng Zeng, Yanfeng Zhang, Meng Li, Wei Wei, Yuhan Sun
      Non-seeded ultrafast microwave synthesis of all-silica DDR zeolite was realized using 1-adamantane amine and tetraethylammonium hydroxide. XRD, SEM, NMR, FT-IR, TGA and nitrogen adsorption were used to characterize the obtained samples. The presence of TEAOH suppressed the formation of other phases which allowed the synthesis to be carried out at high temperature. High quality DDR crystals were obtained in only 30 min without seeding, which is the fastest synthesis up to now. 1-Adam serves as template for zeolite DDR and TEAOH is not occluded in zeolite channels. The ultra fast synthesis is the synergy of fast heating from microwave energy, fast kinetics (nucleation and crystallization) at high temperature and phase selectivity from the TEAOH. The obtained DDR crystals have similar properties as those prepared with traditional method.
      Graphical abstract image

      PubDate: 2016-03-30T13:21:04Z
       
  • Ionothermal synthesis of LTA-type aluminophosphate molecular sieve
           membranes with gas separation performance
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Xiaolei Li, Keda Li, Shuo Tao, Huaijun Ma, Renshun Xu, Bingchun Wang, Ping Wang, Zhijian Tian
      LTA-type aluminophosphate molecular sieve membranes with gas separation performance were ionothermally synthesized by using δ-alumina substrates as both the supports and the aluminum sources. The effects of the synthesis parameters, such as the concentrations of H3PO4, TAMOH, and HF, and the detailed formation process of the membrane were thoroughly investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Furthermore, the subsequent membrane syntheses by using recycled mother liquids were also studied. The results demonstrated that continuous and compact LTA molecular sieve membranes can be prepared over a relatively wide range of the synthesis composition. The membranes prepared with fresh and recycled mother liquids exhibit the same crystallinity, morphology and the gas separation performance. Typically, for single-component gases at 293 K, the ideal separation factors of H2/CO2, H2/O2, H2/N2, and H2/CH4, are 10.9, 8.1, 6.8, and 4.8, respectively, which suggests the good gas separation performance of the membranes.
      Graphical abstract image

      PubDate: 2016-03-30T13:21:04Z
       
  • SBA-15:TiO2 nanocomposites. I. Synthesis with ionic liquids and properties
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Alice A.M.L.F. Jardim, Rebeca Bacani, Fernanda F. Camilo, Márcia C.A. Fantini, Tereza S. Martins
      Nanosized titanium dioxide (TiO2) has been extensively studied due to its unique properties and broad applicability. However, to our knowledge, the assessment on how reaction media and synthesis routes affect TiO2 properties synthesized with SBA-15 type mesoporous silica is unprecedented. In this work, SBA-15/TiO2 nanocomposites were prepared in different reaction media, varying ionic liquids (CMITf2N and CMIBF4) with and without isopropyl alcohol. X-ray diffraction results showed that CMIBF4 greatly favors TiO2 anatase crystalline phase, and a single phase material was obtained using 0.032 of CMIBF4 without alcohol. On the other hand, the presence of CMITf2N slightly favored TiO2 rutile crystalline phase. Small Angle X-ray diffraction patterns revealed that ordered mesoporous SBA-15/TiO2 nanocomposites were obtained with lower ionic liquid concentration, whilst materials prepared with higher concentration lost their ordered mesoporous structure. Scanning electron microscopy images showed that materials prepared with ionic liquid and isopropyl alcohol displayed much smaller SBA-15 particle size: around 0.1 μm, instead of the standard 1 μm. Nitrogen adsorption–desorption analysis showed that the nanocomposites exhibited a narrow pore size distribution with high surface areas of up to 680 m2/g, pore volumes of up to 1.8 cm3/g and mean pore diameter of up to 10.4 nm, thus being very promising for application in photocatalysis and photoprotection.
      Graphical abstract image

      PubDate: 2016-03-30T13:21:04Z
       
  • High azobenzene functionalization enhances stability of the cis isomer:
           Periodic mesoporous organosilica network on the way to new light triggered
           applicable materials
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Jana Timm, Ulrich Schürmann, Lorenz Kienle, Wolfgang Bensch
      Azobenzene and its derivatives are in the focus of research for the application as molecular switch for medical uses or industrial processes. An optical switchable azobenzene molecule was covalently anchored on the pore walls of a benzene molecule bridged periodic mesoporous organosilica material (abbreviated bz-PMO). The two step synthesis allowed the preparation of a hybrid material with a very high switch density exhibiting an extraordinary long half-life time of 87 h of the cis-isomer. The material was thoroughly characterized applying UV/Vis- and solid state NMR-spectroscopy demonstrating the successful covalent anchoring of the switch onto the pore walls.
      Graphical abstract image

      PubDate: 2016-03-30T13:21:04Z
       
  • Preparation and characterization of novel microporous ultrafiltration PES
           membranes using synthesized hydrophilic polysulfide-amide copolymer as an
           additive in the casting solution
    • Abstract: Publication date: 1 July 2016
      Source:Microporous and Mesoporous Materials, Volume 228
      Author(s): Aazam Jalali, Abbas Shockravi, Vahid Vatanpour, Mohsen Hajibeygi
      Novel asymmetric microporous polyethersulfone (PES)/polysulfide-amide (PSA) blended ultrafiltration membranes with superior properties were prepared using the phase inversion induced by immersion precipitation method. The hydrophilic PSA copolymer with nitro groups, thiazole rings, and thioether linkages was synthesized via phosphorylation polycondensation. Different concentrations of the copolymer were used in the PES casting solutions for improving membrane properties and the results were compared with polyvinyl pyrrolidone (PVP)/PES membrane. The presence of amide band, correlated with the stretching vibration of the carbonyl group and bending vibration of NH group on the ATR-FTIR spectra of the modified membranes confirmed the existence of PSA in the PES membrane structure. The cross-section SEM images showed that the membranes with lower skin layer thickness were formed by addition of PSA in the casting solution. Not only the pure water and BSA solution flux of the blended membranes were increased by enlarging PSA concentrations in the casting solutions up to 2% PSA, but also antifouling properties were improved. Comparing PSA with PVP additive showed that the PSA could improve membrane hydrophilicity, porosity, permeability and antifouling properties. However, the PVP has better performance in case of the porosity and the permeability improvement. Therefore, for coupling of the effect of these two additives, the membrane with 1 wt% PVP and 1 wt% PSA was prepared. The results showed that the prepared membrane had good solution flux with good antifouling properties.
      Graphical abstract image

      PubDate: 2016-03-30T13:21:04Z
       
 
 
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