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21.
To decrease the water pollution of textile industries with a large amount of toxic and non‐biodegradable colored dye effluents, an efficient technique is required to safely remove harmful pollutants. In this paper, the reaction between azo dyes and NaBH4 catalyzed by nanoparticles (NPs) thin films has been studied. We report insitu degradation of methyl orange (MO) and methyl red (MR) by using Pt‐based thin films monitored by UV–Vis spectroscopy. We have synthesized different thin films such as Pt, PtPd, PtFeFe2O3, PtNi and PtAu films from Pt organometallic precursor in the MO and MR medium (dye degradation and NPs formation is happened simultaneously) and activity of these films were compared in the complete degradation of MO and MR dyes. Rate constants for the catalyzed reactions have been determined. PtPd NPs thin film has shown the highest rate constant for the degradation of MO and MR within only a few seconds due to its well‐ordered structure. Furthermore, the effect of presence of MO on the morphology of NPs was investigated. 相似文献
22.
In this study, the organosilane‐functionalized graphene oxide as a stabilizer was prepared by a facile one‐step silylation approach. [Cu(PPh3)3Cl] complex was successfully immobilized onto the graphene oxide surface through coordination interaction with organosilane ligand spacers. The supported catalyst showed enhanced catalytic performance toward Sonogashira reaction of aryl halides with phenylacetylene in water solvent compared with the homogeneous analogues, and it could be readily recycled and reused several times without discernible loss of its activity. 相似文献
23.
Iraj Salimikia Rouhollah Heydari Fatemeh Yazdankhah 《Journal of the Iranian Chemical Society》2018,15(7):1593-1601
A solid-phase microextraction fiber was prepared by polyaniline/graphene oxide nanocomposite as sorbent on the surface of a platinized stainless steel wire using electrospinning technique. The nanocomposite structure was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The polyaniline/graphene oxide nanocomposite fiber was used for the determination of nicotine from tobacco samples using headspace solid-phase microextraction method and gas chromatography–flame ionization detection. Influential experimental variables on the extraction efficiency of nicotine, such as extraction time and temperature, humidity and desorption conditions, were evaluated and optimized. Under the optimal experimental conditions? the limit of detection, linear dynamic range, intraday and inter-days precisions were found to be 0.01 μg g?1, 0.05–700 µg g?1 (R2?=?0.996), 6.9 and 8.1%, respectively. Comparison of the polyaniline/graphene oxide nanocomposite sorbent with polyaniline and commercial fibers shows longer durability, larger capacity and higher extraction efficiency. The polyaniline/graphene oxide nanocomposite fiber was successfully applied for the determination of nicotine in tobacco samples. 相似文献
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Sima Ahmadi Mohammad Taghi Hamed Mosavian Somayeh Heydari 《Journal of the Iranian Chemical Society》2018,15(11):2605-2614
A rapid and simple approach for the preconcentration and determination of catechin from pistachio green hull samples has been proposed by surfactant-assisted dispersive liquid–liquid microextraction followed by UV–Vis spectrophotometry (SADLLME/UV–Vis). This method involved the formation of a catechin complex with cetylpyridinium chloride (CPC) as cationic surfactant, and subsequently, DLLME was applied to extract the catechin–CPC complex into chloroform. Different parameters affected the extraction efficiency were optimized by central composite design (CCD) and response surface methodology (RSM). In optimum condition, the calibration curve was linear in the range of 0.4–5 µg mL??1 of catechin with correlation coefficient of 0.9982. The relative standard deviation based on five replicated analyses of 1 µg mL??1 catechin was 1.85%. The proposed method was successfully applied for preconcentration and determination of trace amounts of catechin in pistachio hull samples. 相似文献
27.
Let (R,m) be a commutative Noetherian regular local ring of dimension d and I be a proper ideal of R such that mAss R (R/I) = Assh R (I). It is shown that the R- module Hht(I) I (R) is I-cofinite if and only if cd(I,R) = ht(I). Also we present a sufficient condition under which this condition the R-module H i I (R) is finitely generated if and only if it vanishes. 相似文献
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Hossein Aminikhah Jafar Biazar 《Numerical Methods for Partial Differential Equations》2010,26(2):480-489
In this paper, we introduce a new version of the homotopy perturbation method (NHPM) that efficiently solves linear and non‐linear ordinary differential equations. Several examples, including Euler‐Lagrange, Bernoulli and Ricatti differential equations, are given to demonstrate the efficiency of the new method. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010 相似文献
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Qamrul Hasan Ansari Mahboubeh Rezaie Jafar Zafarani 《Journal of Global Optimization》2012,53(2):271-284
In this paper, we consider different kinds of generalized vector variational-like inequality problems and a vector optimization problem. We establish some relationships between the solutions of generalized Minty vector variational-like inequality problem and an efficient solution of a vector optimization problem. We define a perturbed generalized Stampacchia vector variational-like inequality problem and discuss its relation with generalized weak Minty vector variational-like inequality problem. We establish some existence results for solutions of our generalized vector variational-like inequality problems. 相似文献