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151.
Matrimid–polyaniline/clay mixed‐matrix membranes with plasticization resistance for separation of CO2 from natural gas
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Mixed‐matrix membranes (MMMs) of Matrimid® and polyaniline/clay (PC) are investigated for CO2/CH4 separation and CO2‐induced plasticization. PC particles are synthesized through in‐situ polymerization of aniline in the presence of organophilic clay and then incorporated into Matrimid by solution casting method. Chemical structure and morphology of PC powder and fabricated membranes are analyzed by Fourier transform infrared (FTIR), X‐ray diffraction (XRD), differential scanning calorimetry/thermogravimetric analysis (DSC/TGA) and scanning electron microscopy (SEM). The XRD spectra of PC particles show the exfoliation of silicate layers throughout the polyaniline (PAni) matrix, and SEM images indicate flower‐petal morphology for PC particles. The permeability values of CO2 and CH4 increase 30–35% by incorporation of 10 wt% PC without any significant drop in selectivity. PC particles with flower‐petal morphology plays an important role in increasing the gas permeability values of both gases while Matrimid is the only phase that controls CO2/CH4 selectivity. The plasticization pressure was increased to 30 bar by incorporation of 10 wt% PC in the Matrimid matrix. CO2 permeability and pplast improved 35% and 200%, respectively, resulting in 300% enhancement in the capacity of MMM in the purification of natural gas with a selectivity of about 40. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
152.
Fabrication and characterization of CMC‐based magnetic superabsorbent hydrogel nanocomposites for crystal violet removal
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In this research work, novel magnetic superabsorbent hydrogel nanocomposites (MSHNs) based on carboxymethyl cellulose were prepared via a facile “one‐pot” two step approach. Magnetic iron oxide nanoparticles were in situ synthesized and incorporated into carboxymethyl cellulose/poly(acrylic acid) polymer hydrogel. The morphology and chemical composition of MSHNs as well as the presence of magnetic iron oxide nanoparticles were evaluated by using Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X‐Ray diffraction, ultraviolet–visible spectroscopy, thermogravimetric analysis, and vibrating sample magnetometer. The effect of different reaction parameters on the swelling capacity of MSHNs was investigated. Furthermore, batch adsorption experiments of crystal violet dye onto MSHNs were studied by varying solution pH, initial dye concentration, and temperature. Evaluation of thermodynamic parameters of crystal violet adsorption confirmed that the adsorption was spontaneous and endothermic process in nature. The equilibrium study revealed that the dye adsorption behavior of MHSNs followed the Redlich‐Peterson isotherm model. Finally, the dye adsorption experiment data was well fitted by the pseudo‐second‐order kinetic model with the regression coefficient (R2) of 0.9979. Our results suggest that the MHSNs with facile preparation method, high swelling capacity, and high dye adsorption capacity may be used as promising adsorbents for fast removal of various dyes from aqueous solutions. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
153.
Transparent polymer materials, due to their unique properties, such as light weight, optical transparency, and electrical and mechanical properties, have become very attractive as a replacement for inorganic glass substrates in a wide range of optoelectronic applications. In this research, aluminum zinc oxide nanostructured thin film was deposited on polycarbonate polymer substrates using a magnetron sputtering technique. The structure, morphology, and surface composition of the thin film were investigated by X-ray diffraction and field emission scanning electron microscopy. The optical and electrical properties of the thin film were investigated by UV–VIS-NIR spectrophotometer, ellipsometer, and four point probe method. The X-ray diffraction pattern showed that the aluminum zinc oxide thin film had a polycrystalline structure. The optical and electrical results indicated that the refractive index, band gap, and sheet resistance of the aluminum zinc oxide thin film were 1.8, 3.2 eV, and 265 Ω/sq, respectively. 相似文献
154.
Ali Akbar Ashkarran 《Applied Physics A: Materials Science & Processing》2012,107(2):401-410
Ag:ZnO hybrid nanostructures were successfully prepared by a twice arc discharge method in liquid. The visible light photocatalytic
activities were successfully demonstrated for the degradation of Rhodamine B (Rh. B), Methyl orange (MO), and Methylene blue
(MB) as standard organic compounds under the irradiation of 90 W halogen light for 2 h. The Ag:ZnO nanostructures were characterized
by X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and ultraviolet-visible
absorption spectroscopy (UV-Vis). The results revealed that the Ag:ZnO nanostructures extended the light absorption spectrum
toward the visible region and significantly enhanced the Rh. B photodegradation under visible light irradiation. 3 mM Ag:ZnO
nanostructures exhibited highest photocatalytic efficiency. It has been confirmed that the Ag:ZnO nanostructures could be
excited by visible light (E<3.3 eV). The significant enhancement in the Ag:ZnO nanostructures photocatalytic activity under visible light irradiation
can be ascribed to the effect of physisorbed noble metal Ag by acting as electron traps in ZnO band gap. A mechanism for photocatalytic
degradation of organic pollutant over Ag:ZnO photocatalyst was proposed based on our observations. 相似文献
155.
Mohammad Akbar Ali Ai Ling Tan Aminul Huq Mirza Jose H. Santos Aimi Hanisah Bte Hj Abdullah 《Transition Metal Chemistry》2012,37(7):651-659
Four tridentate ONS ligands, namely 2-hydroxyacetophenonethiosemicarbazone (H2L1), the 2-hydroxyacetophenone Schiff base of S-methyldithiocarbazate (H2L2), the 2-hydroxy-5-nitrobenzaldehyde Schiff base of S-methyldithiocarbazate (H2L3), and the 2-hydroxy-5-nitrobenzaldehyde Schiff base of S-benzyldithiocarbazate (H2L4), and their complexes of general formula [Ni(HL1)2], [ML] (M?=?NiII or CuII; L?=?L1, L2, L3 and L4), [Co(HL)(L); L?=?L1, L2, L3 and L4] and [ML(B)] (M?=?NiII or CuII; L?=?L2 and L4; B?=?py, PPh3) have been prepared and characterized by physico-chemical techniques. Spectroscopic evidence indicates that the Schiff bases behave as ONS tridentate chelating agents. X-ray crystallographic structure determination of [NiL2(PPh3)] and [CuL4(py)] indicates that these complexes have an approximately square-planar structure with the Schiff bases acting as dinegatively charged ONS tridentate ligands coordinating via the phenoxide oxygen, azomethine nitrogen and thiolate sulfur atoms. The electrochemical properties of the complexes have been studied by cyclic voltammetry. 相似文献
156.
Cr doped TiO2-SiO2 nanostructure thin film on glass substrates was prepared by a sol-gel dip coating process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the structural and chemical properties of the films. A UV-vis spectrophotometer was used to measure the transmittance spectra of the thin film. The hydrophilicity of the thin film during irradiation and storage in a dark place was measured by a contact angle analyzer. The results indicated that Cr doping has a significant effect on the transmittance and super-hydrophilicity of TiO2-SiO2 thin film. 相似文献
157.
Marcel Morales Ali Akbar Yazdan Pour Rashid Zaare-Nahandi 《Journal of Pure and Applied Algebra》2012,216(12):2714-2719
In this paper, we introduce some reduction processes on graphs which preserve the regularity of related edge ideals. Using these, an alternative proof for the theorem of R. Fröberg on the linearity of the resolutions of edge ideals is given. 相似文献
158.
Sattar Ebrahimi Akbar Mobinikhaldei Naser Foroughifar 《Journal of heterocyclic chemistry》2012,49(4):955-958
A practical and regioselective synthetic method for the synthesis of cis‐diastereomers of bibracchial lariat ethers (BiBLEs) bearing ester and amide groups is reported. The novel BiBLEs 3a and 4a–e with neutral side arms were prepared by reaction of the corresponding aza‐crown macrocycles 1a – c with ethylchlroacetate and chloroacetamide. The structures of the new compounds have been confirmed by FTIR, 1H, 13C, DEPT, and MS spectroscopy. 相似文献
159.
Akbar Mohebbi Zohreh Asgari Mehdi Dehghan 《Communications in Nonlinear Science & Numerical Simulation》2012,17(12):4602-4610
In this work we investigate the numerical solution of Jaulent–Miodek (JM) and Whitham–Broer–Kaup (WBK) equations. The proposed numerical schemes are based on the fourth-order time-stepping schemes in combination with discrete Fourier transform. We discretize the original partial differential equations (PDEs) with discrete Fourier transform in space and obtain a system of ordinary differential equations (ODEs) in Fourier space which will be solved with fourth order time-stepping methods. After transforming the equations to a system of ODEs, the linear operator in JM equation is diagonal but in WBK equation is not diagonal. However for WBK equation we can also implement the methods such as diagonal case which reduces the CPU time. Comparing numerical solutions with analytical solutions demonstrates that those methods are accurate and readily implemented. 相似文献
160.
Akbar Hashemi Borzabadi Mohammad Heidari 《Journal of Mathematical Modelling and Algorithms》2012,11(1):77-88
In this paper, optimal control problem (OCP) governed by the heat equation with thermal sources is considered. The aim is
to find an optimal control which puts the system in a finite time T, into a stationary regime and to minimize a general objective function. To obtain an approximate solution of this problem,
a partition of the time-control space is considered and the discrete form of the problem is converted to a quasi assignment
problem. Then by using an evolutionary algorithm, an approximate optimal control function is obtained as a piecewise linear
function. Numerical examples are given to show the proficiency of the presented algorithm. 相似文献