Efficient removal of low concentration methyl mercaptan by HKUST-1 membrane constructed on porous alumina granules

A HKUST-1 metal-organic framework membrane was constructed on porous Al2O3 granules for the first time for the removal of low concentration CH3SH. The granules exhibited higher sulfur capacity than the pure HKUST-1 powders owing to the excellent dispersion of the MOF membrane on the Al2O3 substrate. The granules also showed good water resistibility

mechanismofdichloromethanedisproportionationovermesoporoustio2underlowtemperature

Mesoporous tio2 was synthesized via nonhydrolytic template-mediated sol-gel route. catalytic degradation performance upon dichloromethane over as-prepared mesoporous tio2, pure anatase and rutile were investigated respectively. disproportionation took place over as-made mesoporous tio2 and pure anatase under the presence of water. the mechanism of disproportionation was studied by in situ ftir. the interaction between chloromethoxy species and bridge coordinated methylenes was the key step of disproportionation. formate species and methoxy groups would be formed and further turned into carbon monoxide and methyl chloride. anatase (001) played an important role for disproportionation in that water could be dissociated into surface hydroxyl groups on such structure. as a result, the consumed hydroxyl groups would be replenished. in addition, there was another competitive oxidation route governed by free hydroxyl radicals. in this route, chloromethoxy groups would be oxidized into formate species by hydroxyl radicals transfering from the surface of tio2. the latter route would be more favorable at higher temperature. (c) higher education press and springer-verlag gmbh germany, part of springer nature 201

mechanismofdichloromethanedisproportionationovermesoporoustio2underlowtemperature

Mesoporous TiO2 was synthesized via nonhydrolytic template-mediated sol-gel route.Catalytic degradation performance upon dichloromethane over as-prepared mesoporous TiO2,pure anatase and rutile were investigated respectively.Disproportionation took place over as-made mesoporous TiO2 and pure anatase under the presence of water.The mechanism of disproportionation was studied by in situ FTIR.The interaction between chloromethoxy species and bridge coordinated methylenes was the key step of disproportionation.Formate species and methoxy groups would be formed and further turned into carbon monoxide and methyl chloride.Anatase(001)played an important role for disproportionation in that water could be dissociated into surface hydroxyl groups on such structure.As a result,the consumed hydroxyl groups would be replenished.In addition,there was another competitive oxidation route governed by free hydroxyl radicals.In this route,chloromethoxy groups would be oxidized into formate species by hydroxyl radicals transfering from the surface of TiO2.The latter route would be more favorable at higher temperature

Reactive adsorption of low concentration methyl mercaptan on a Cu-based MOF with controllable size and shape

A copper-based metal organic framework (MOF-199) with controllable size and shape was synthesized and used to remove gaseous methyl mercaptan (CH3SH). Characterizations of the synthesized MOF-199 samples before and after desulfurization were carried out by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) to observe the adsorption mechanism of CH3SH on MOF-199. The adsorption performance of the synthesized MOF-199 materials and commercialized activated carbon (AC) and Cu loaded AC were evaluated by breakthrough experiments. All three synthesized MOF-199 materials show better performance than commercialized AC. The morphology and texture of MOF-199 materials have great influence on the performance of the adsorption process. The MOF-199 material synthesized by a hydrothermal method exhibited the highest sulfur compound capacity among the synthesized MOF-199 materials (74.7 mg of CH3SH/1 g MOF-199). The color change of MOF-199 during the CH3SH capturing process, indicated a strong interaction between the unsaturated copper sites and -SH group which finally formed CuS and gave rise to obvious damage to the MOF structure.</p

Mechanism of dichloromethane disproportionation over mesoporous TiO2 under low temperature

Mesoporous TiO2 was synthesized via nonhydrolytic template-mediated sol-gel route. Catalytic degradation performance upon dichloromethane over as-prepared mesoporous TiO2, pure anatase and rutile were investigated respectively. Disproportionation took place over as-made mesoporous TiO2 and pure anatase under the presence of water. The mechanism of disproportionation was studied by in situ FTIR. The interaction between chloromethoxy species and bridge coordinated methylenes was the key step of disproportionation. Formate species and methoxy groups would be formed and further turned into carbon monoxide and methyl chloride. Anatase (001) played an important role for disproportionation in that water could be dissociated into surface hydroxyl groups on such structure. As a result, the consumed hydroxyl groups would be replenished. In addition, there was another competitive oxidation route governed by free hydroxyl radicals. In this route, chloromethoxy groups would be oxidized into formate species by hydroxyl radicals transfering from the surface of TiO2. The latter route would be more favorable at higher temperature. (c) Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature 201

mechanismofdichloromethanedisproportionationovermesoporoustio2underlowtemperature

Mesoporous TiO2 was synthesized via nonhydrolytic template-mediated sol-gel route.Catalytic degradation performance upon dichloromethane over as-prepared mesoporous TiO2,pure anatase and rutile were investigated respectively.Disproportionation took place over as-made mesoporous TiO2 and pure anatase under the presence of water.The mechanism of disproportionation was studied by in situ FTIR.The interaction between chloromethoxy species and bridge coordinated methylenes was the key step of disproportionation.Formate species and methoxy groups would be formed and further turned into carbon monoxide and methyl chloride.Anatase(001)played an important role for disproportionation in that water could be dissociated into surface hydroxyl groups on such structure.As a result,the consumed hydroxyl groups would be replenished.In addition,there was another competitive oxidation route governed by free hydroxyl radicals.In this route,chloromethoxy groups would be oxidized into formate species by hydroxyl radicals transfering from the surface of TiO2.The latter route would be more favorable at higher temperature

Removal of low concentration CH3SH with regenerable Cu-doped mesoporous silica

Mercaptans are highly volatile compounds responsible for disagreeable odors and very low olfactory threshold, especially for CH3SH (0.4 ppvb). To the best knowledge of us, approach for controlling low concentrated odors (i.e. 1-10 ppm) is scarcely reported. In this research, Cu-doped mesoporous silica was synthesized for removal of low-concentrated CH3SH. The as-prepared samples show considerably thermal and mechanical stability and could be thermal-regenerated. Copper loading ratio and humidity have significant impacts on eliminating odors. According to XRD, TEM, BET, NMR and EPR, we deduce that surface groups on CuO nanoparticles and the Si-O-Cu group are highly possibly transformed into a hydrated complex which is much more effective in capturing CH3SH with its empty Cu-3d orbit. Although CH3SH has to compete with water for absorption sites, it is always the &quot;winner&quot; owing to the strong chelating ability between-SH group and Cu (II). (C) 2017 Elsevier Inc. All rights reserved.</p

Promotional effects of Ce on the activity of Mn-Al oxide catalysts derived from hydrotalcites for low temperature benzene oxidation

Ce/MnAl and MnAl mixed metal oxides catalysts have been obtained by calcination of layered double hydroxides precursors. The composite oxides catalysts were studied in total oxidation of benzene. Physicochemical properties of all the catalysts were characterized by using a series of specific analytical techniques. The results revealed that the 0.2Ce/MnAl catalyst exhibited the highest catalytic performance with T-90 about 210 degrees C at a high space velocity (SV = 60,000 mL g(-1), h(-1)), ascribed to its lower-temperature reducibility, the abundant surface lattice oxygen (O-latt), and synergetic effect between Mn4+ and Ce3+/Ce. (C) 2016 Published by Elsevier B.V.</p

Spherical Al2O3-coated mullite fibrous ceramic membrane and its applications to high-efficiency gas filtration

Porous ceramic membranes (PCMs) have been widely used in gas filtration to reduce the Particulate Matters (PMs) emission from industrial systems. Generally, the filter materials are composed of two parts: the support layer and filter layer. However, the typical PCMs prepared through accumulation of particles have existing problems like heavy self-weight, low porosity and high pressure drop, which limit their use in practical applications. In this paper, fibrous PCMs with three-dimensional structures were prepared and then coated with a layer of spherical alpha-Al2O3 membrane on the surface via spray-coating process. The effect of binder composition and sintering temperature on the porosity, phase composition, bulk density and mechanical strength of PCMs, as well as the effect of the coating thickness of spherical alpha-Al2O3 on PMs filtration efficiency and pressure drop were investigated. The results showed that samples with an added binder weight of 50 wt% and sintered at 1250 degrees C resulted to an optimal structure with material properties such as low bulk density (0.88 g/cm(3)), high porosity (70.36%), low linear shrinkage (0.40%), high mechanical strength (5.54 Mpa), and excellent corrosion resistance against both acid and alkali solutions. Furthermore, a spherical alpha-Al2O3 coating thickness of 150 mu m was found to effectively reduced the concentration of PMs from dust-laden air through the filtration tests, achieving enhanced dust removal efficiencies of almost 100% for 3-10 mu m, 99.2% for 1.0 mu m, 95.0% for 0.5 mu m and 91.6% for 0.3 mu m PMs with the pressure drop was only 280 Pa when the airflow linear velocity reached to 2.00 m min(-1). The membranes displayed a 10% increase efficiency in fine particles (d = 1.0-0.3 mu m) removal compared to those without alpha-Al2O3 coating layer

Highly porous fibrous mullite ceramic membrane with interconnected pores for high performance dust removal

Porous fibrous mullite ceramic membranes with different content of fibers were successfully fabricated by molding method for dust removal. The properties of the samples, such as microstructure, porosity, bulk density and mechanical behavior were analyzed. Owing to the highly porous three-dimensional structure of ceramic membranes, all the samples exhibited low density (lower than 0.64 g/cm(3)), high porosity (higher than 73%), low linear shrinkage (lower than 1.0%) and low thermal conductivity (lower than 0.165 W/mK). Significantly, the as-prepared porous ceramic membrane possessed of enhanced dust removal efficiency with almost 100% for 3-10 mu m, 97% for 1.0 mu m, 87% for 0.5 mu m and 82% for 0.3 mu m dust particles in diameter from dust-laden air passed through the test module. Moreover, the pressure drop was lower than 80 Pa when the airflow linear velocity reached 1.25 m min(-1). The results indicated that the ceramic membranes prepared in this work were promising high efficiency dedusting materials for the application in gas filtration field.</p