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Polyaniline (PANI) as an excellent conducting polymer was used to prepare an organic–inorganic hybrid nanocomposite based on nitrogen (N)‐doped titanium dioxide (TiO2) under different synthesis conditions. Based on the DRS, XRD, FESEM, BET, XPS, and FT‐IR results, the optical and structural properties of the as‐prepared composites were found to be affected by N‐TiO2 to aniline (ANI) molar ratio, reaction time, and initial pH of solution, which in turn influence the photocatalytic performance of nanocomposites. The experimental design methodology was used to study the simultaneous effect of these synthesis parameters on the Vis activity performance of N‐TiO2/PANI nanocomposites for degradation of Acid Red 73. The degradation efficiency was significantly affected by the reaction time of polymerization, initial pH of solution, and interaction between the reaction time and N‐TiO2/ANI molar ratio. The optimal synthesis conditions for maximum Acid Red 73 degradation efficiency (58.25%) were found to be a molar ratio of N‐TiO2/ANI of 106.13 M, the reaction time of 487.42 min, and pH of 3.37. TEM images, N2 adsorption–desorption isotherms and BET analysis of the as‐prepared nanocomposites show the increase in surface area and porosity and decrease in agglomeration formation by adding nitrogen and PANI. The N‐TiO2/PANI nanocomposites prepared at optimal synthesis conditions show higher visible activity compared to those modified with nitrogen or PANI only due to the synergistic effect between PANI and N doping. The mineralization studies of Acid Red 73 using the as‐prepared nanocomposites show their ability to decompose approximately all organic compounds present in the solution. POLYM. COMPOS., 39:4605–4616, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In order to calculate the permeability of gases in mixed matrix membranes (MMMs) filled with porous particles, the first step is to calculate the permeability of filler particles. Because particle pore sizes of the considered sodium zeolite Y (NaY) in this study is greater than the molecular sizes of the tested gases (CO2 and N2), it is assumed that diffusion of the gases in the zeolite particles is from Knudsen type. Moreover, the gas sorption data (isotherms) were measured experimentally and then fitted with Langmuir and Freundlich model equations to calculate the related constants. Finally, the experimental CO2 and N2 permeabilities of cellulose acetate (CA)/NaY MMMs were compared with the corresponding data predicted by the well‐known permeability models in this field. It was concluded that the Bruggeman model has better predictions among the other models, especially for the higher particle loadings. POLYM. COMPOS., 39:4560–4568, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

CuBTC and NH2-CuBTC metal organic frameworks (MOF) were used to produce mixed matrix membranes (MMM) with a block copolymer of poly(ether-b-amide-6) (Pebax® MH 1657) as the polymer matrix to investigate the effect of amine functionalized group (-NH2) on the CO2/CH4 gas separation performance of the MMM. The MOF were fully characterized by XRD, FTIR-ATR, TGA, N2, CO2, and CH4 adsorption, while the MMM were characterized using FTIR-ATR, TGA, DSC, and SEM. Permeability and selectivity of the MMM were studied at different MOF mass contents (5 to 20 g/g) and feed pressures (0.3 to 1.5 MPa) for pure and mixed gases. The CO2 permeability for 20 g/g of both Pebax/CuBTC and Pebax/NH2-CuBTC MMMs was nearly twice that of the neat polymeric membrane, while the presence of amine functionalized group in NH2-CuBTC produced an increasing trend of CO2/CH4 ideal selectivity at high NH2-CuBTC loading and about a 60 % increase was observed at 20 g/g of NH2-CuBTC. [ABSTRACT FROM AUTHOR]

In this work, poly (ether-block-amide) (Pebax MH 1657) mixed matrix membranes (MMMs) were prepared using nanoporous ZSM-5 as a filler. The fabricated membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimeter (DSC) analysis, thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). Effects of zeoilte loading (5, 10 and 15 wt. %), and feed pressure (1, 3 and 5 bar) on CO2/CH4 separation of MMMs were investigated using constant volume/variable pressure system. SEM analysis represents a proper morphology along with proper dispersion of ZSM-5 particles within the polymer matrix. TGA analysis demonstrated that the thermal degradation temperature (Td) of MMMs increased by increasing the ZSM-5 loading. The obtained experimental results showed that both permeability and CO2/CH4 selectivity enhanced by addition of zeolite compared to neat Pebax. At low concentration of zeolite (5 wt. %), the CO2 permeability increased significantly from 122.4 Barrer to 217.9 Barrer at pressure of 1 bar. MMM that incorporated by 15 wt. % of zeolite showed the best CO2/CH4 selectivity of 33.9 at pressure of 1 bar. The CO2 permeability of MMM with 5 wt. % ZSM-5 enhanced from 217.9 to 292.4 Barrer with increase in feed pressure from 1 to 5 bar. Copyright © 2016 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Polyethylene glycols have received worldwide attention as a highly permeable CO2-philic polymer in carbon dioxide separation applications. In this study, we investigated the influence of a low molecular weight polyethylene glycol (PEG 200) on physicochemical, morphological, and gas separation properties of Matrimid®5218 as a novel polymer blend. Both symmetric and asymmetric Matrimid flat sheet membranes with 0-20 wt.% PEG were prepared via a dense film-casting method. The miscibility of blends at low PEG concentrations (3-5 wt.%) was confirmed by differential scanning calorimetry (DSC) and polarized light microscopy (PLM). Moreover, the blends were partially miscible at higher PEG concentrations (10-20 wt.%). Matrimid/PEG molecular interactions were further studied by FTIR and XRD analysis. SEM images indicated an impressive influence of PEG on the symmetric structure of Matrimid membrane. An asymmetric structure with a dense thin skin layer and a highly porous sub-layer was observed for the blends containing 10-20 wt.% PEG. The CO2 permeability and CO2/CH4 selectivity of the best-yield CO2-selective blend membrane (Matrimid/PEG (95:5)) incvreased about 25% (from 7.68 to 9.62 Barrer) and 15% (from 35 to 40) compared to pure Matrimid, respectively. Furthermore studying the plasticization pressures of the membranes revealed that the more PEG content in blend the less the plasticization pressure obtained. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Oxidative desulfurization of thiophenic sulfur compounds of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) with MoO x /Al 2 O 3 catalyst and H 2 O 2 oxidant has been facilitated and more selective under ultrasonic irradiation. The catalyst with the optimum 10% of Mo loading consisted of isolated tetrahedral molybdenum oxide species based on FTIR analysis. The increase of Mo loading to 15% and 20% caused to generation of polymolybdate and MoO 3 crystals which decreased desulfurization activity. Sonication enhanced the apparent reaction rate constants in oxidation of all three sulfur compounds. An increase in the Arrhenius factor ( A 0 ), which is the total number of collisions per second, could explain the acceleration in the rate constants by sonication. The apparent activated energy ( E a ) of BT oxidation was reduced from 96.6 to 75.3 kJ/mol by using ultrasound. This indicated that ultrasound had also a chemical effect, like a catalytic influence, in the acceleration of BT removal. DBT oxidation was reduced when investigated in the presence of tetralin, naphthalene and 2-methyl naphthalene as the model aromatic compounds of actual light oils. A higher selectivity toward DBT elimination in the presence of aromatics was obtained by sonication when compared with the silent treatment. Ultrasound cleaned the catalyst surface from adsorbed aromatics. On the basis of the obtained results, a mechanistic proposal for this desulfurization was explained. Oxidation was performed by nucleophilic attack of sulfur atom to the molybdenum peroxide species of tetrahedral molybdates, which was more advanced by sonication. [ABSTRACT FROM AUTHOR]

In this study, gas separation properties of Matrimid/MIL-53 mixed matrix membranes with different MOF weight percentages (0-20 wt.%) were investigated. TEM, XRD and DLS analysis were implemented to investigate MIL-53, structure and particles size distribution. SEM, FTIR, DSC and TGA analyses were conducted to characterize the fab-ricated membranes. The SEM images of these membranes showed good adhesion between polymer and particles, although for 20% MIL-53 loading, particles agglomeration was observed in some areas. Moreover, surface images of the membranes showed adequate dispersion of the particles in the polymer matrix, especially at lower MOF loadings. The permeability of pure CO2 and CH4 gases for all membranes were measured and the ideal CO2/CH4 selectivity was calculated. CH4 permeability of membranes increased slightly as the percentage of loading increased. At 20 wt.% MOF loading, void formation led to a significant increase in CH4 permeability (300% over pure Matrimid). CO2 per-meability showed the same trend; there was a 94% increase in permeability compared to pure Matrimid for 15 wt.% MMMs. CO2/CH4 selectivity also increased as MOF loading increased. The highest selectivity was shown for 15 wt.% MOF loading. This membrane had 84% growth in selectivity over pure Matrimid. Although at 20 wt.% MIL-53 loading, membrane separation performance was destroyed. [ABSTRACT FROM AUTHOR]

The drive toward greater application of membrane has resulted in its rapid development in natural gas processing industry. In this work, amine-mediated membranes were tailored for CO2 removal from CO2/CH4 stream. The effects of various parameters such as amine concentration, microporous support, feed pressure and composition were examined to study the permeation behavior of pure and mixed gases. Generally, CO2 transport through the DEA-PVA membranes was higher than that of MEA-PVA membranes for approximately 70%. The membrane containing 15 wt% DEA and 35 wt% MEA revealed higher permselectivity. CO2 permeance enhancement of amine-PVA membranes in comparison with neat PVA membrane, confirmed that CO2-amine reaction was the dominant transport mechanism. Additionally, with increasing feed pressure, CO2/CH4 permselectivity decreased due to carrier saturation. However, lower partial pressure of CO2 was in favor of reaction mechanism in pure and mixed gas tests. On the other hand, CH4 is not significantly affected by feed pressure confirming that solution-diffusion is the governing transport mechanism. Additionally, PTFE support with higher wettability showed better performance (+8%) regardless of amine type, concentration and feed pressure. DEA-PVA membrane has exhibited good stability during 2 weeks, unlike MEA-impregnated membrane, which was probably due to carrier degradation over time. POLYM. ENG. SCI., 54:1268-1279, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Highlights: [•] A new sonocatalytic system was developed for oxidative desulfurization of diesel. [•] The sonocatalytic process provided higher efficiency contrary to the silent system. [•] CCD method was applied to investigate the effects of main process variables. [•] Ultrasonication accelerated ODS process interestingly for high sulfur concentration. [•] Ultrasonication significantly promoted the catalyst stability and properties. [Copyright &y& Elsevier]

In this paper, polyvinyl alcohol (PVA) membranes impregnated with amines (monoethanolamine and diethanolamine) were prepared for CO2/N2 separation. The cross-linking of DEA impregnated PVA by glutaraldehyde (GA) with different mass ratios (GA/PVA: 0.5, 1, 3, 5, 7%) were investigated with no use of acid catalyst or organic solvents. The effects of the amine type-concentration, cross-linking agent content, and feed pressure as well as stability were examined in both pure and mixed gases. Generally, CO2/N2 performance through the DEA-PVA membranes was higher than that of MEA-PVA membranes. The fabricated membranes were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The cross-linked membranes showed reasonable CO2/N2 permselectivities in comparison with uncross-linked membranes and these are recommended for high performance membrane for CO2/N2 separation. The best-yielding membranes (DEA-PVA/GA(1 wt%)/PTFE) represented the greatest CO2/N2 selectivity of 122.04 and 907.06 for pure and mixed gas experiments, respectively. [ABSTRACT FROM AUTHOR]

In this research, Pebax1657 as an organic phase and silver nanoparticles as an inorganic phase were used for preparation of binary mixed matrix membranes (MMMs). Silver nanoparticles as a filler could enter the polymer chains and enhance the gas permeability by increasing the fractional free volume of membranes. Afterward, ternary MMMs were fabricated by addition of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]) ionic liquid, in order to have better polymer/filler adhesion and eliminate interfacial defects and nonselective voids. In addition, positively polarized silver nanoparticles in the presence of the IL could interact with PEO segment of the polymer and increase the CO 2 affinity of membranes, which results in increasing the CO 2 /light gases permselectivity of MMMs. Gas permeation properties of MMMs were studied at a temperature of 35 °C and operating pressures from 2 to 10 bar. Moreover, fabricated membranes were characterized by fourier transform infrared-attenuated total reflectance (FTIR-ATR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimeter (DSC). The analysis revealed that there is a proper adhesion between positively charged surface of nanoparticles and the polymer, and both filler and IL decrease the crystallinity of the membranes, which could enhance the polar gas transport properties. Gas permeation results showed significant enhancement in CO 2 permeability (325 Barrer) for binary membrane (Pebax 1657/1%Ag) at 35 °C and 10 bar. Moreover, ternary MMM (Pebax 1657/0.5%Ag/50%IL) encountered significant increase in both permeability and selectivity in comparison with neat membrane. Indeed, the CO 2 permeability increased from 110 Barrer to 180 (about 64%). Moreover, the related CO 2 /CH 4 and CO 2 /N 2 selectivities were increased from 20.8 to 61.0 (more than 193%) and from 78.6 to 187.5 (about 139%), respectively.