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91.
Could Voltammetry be an Effective Alternative Technique to Study Adsorption Kinetics of Electroactive Metal Ions? 下载免费PDF全文
Diele A. G. Araújo Ana C. A. Faria Regina M. Takeuchi André L. Santos 《Electroanalysis》2016,28(3):596-600
The suitability of LSV to study adsorption kinetics of metal ions was evaluated using Cu2+ adsorption on Amberlite® IR‐120 as a model system. LSV provided results in agreement with conventional batch method with remarkable decreasing on analysis time and reagents consumption, since no adsorbent/adsorbate separation is required. Adsorption curves can be obtained in situ using only one portion of adsorbate solution. LSV provides higher temporal resolution for adsorption curves, which is indispensable to evaluate adsorption mechanisms and the performance of new adsorbent materials. Therefore, LSV not only saves time and reagents but also provides better quality of kinetic adsorption data. 相似文献
92.
A productive natural method has been produced for the synthesis of 2-aryl-2-methyl-4,5-diphenyl-2,3-dihydro-2H-imidazoles in great yields under catalyst free-conditions utilizing polyethylene glycol (PEG-400) as a green reaction medium. The highlights of this new method are shorter reaction times, good yields, room temperature, and use of nontoxic, inexpensive, and recyclable PEG-400. 相似文献
93.
An efficient La(OTf)3-catalyzed three-component reaction has been developed for the synthesis of highly substituted spiro[indolo-3,10′-indeno[1,2-b]quinolin]-2,4,11′-triones in polyethylene glycol (PEG-400) under conventional heating and ultrasonic irradiation. The most exciting feature of this methodology is its mechanism involving the unusual ring opening of an isatin moiety followed by recyclization. All the reactions resulted in good yield of products. The important features of this reaction are use of green solvent, good yields, less reaction times, and recyclability of the catalyst. 相似文献
94.
A facile, convenient, environmentally benign, and one-pot synthesis of imidazo[1,2-a]pyridines from 2-aminopyridines and in-situ generated phenacyl bromides under microwave irradiation in polyethylene glycol (PEG-400) and water (1:2) has been developed. The protocol provides a better alternative to the existing method as it involves utilization of in-situ-generated α-bromoacetophenones, avoids the use of lachrymatric α-haloketones as well as volatile toxic organic solvents, and reduces the reaction time to obtain excellent yield. 相似文献
95.
96.
《Analytical letters》2012,45(6):443-454
Abstract Scandium was extracted at pH 5.0 from 0.01 M malonic acid on silica gel column impregnated with Amberlite LA-1. Nickel, zinc, cadmium, mercury, lead, tin, aluminium, and lanthanum in binary mixtures because they could not form malonato complexes. It was separated by the process of selective elution from elements such as zirconium, thorium, uranium, iron(III), gallium, indium, cerium(III), litanium by exploiting difference in stability of malonato complexes. Scandium was separated from multicomponent mixture containing yttrium, titanium, zironium, thorium, uranium and aluminium by a process of selective sorbtion and selective elution. 相似文献
97.
《Physics and Chemistry of Liquids》2012,50(5):682-697
This study intends to portray the nature of polymer solutions by ultrasonic velocity and density data. Acoustical parameters, such as relaxation strength, relative association, molecular constant, fractional free volume, available volume, Beyer's non-linearity parameter, internal pressure, van der Waals’ constants and molecular radius have been computed for the binary mixtures of PEG400?+?methanol, PEG400?+?ethanol, PPG400?+?ethanol and PPG400?+?2-propanol systems at 298.15?K. Flory's theory has been used for computing ultrasonic velocity, surface tension, thermal expansion coefficient, thermal conductivity, excess heat capacity and excess isothermal compressibility. Isothermal compressibilities of mixtures have been theoretically evaluated using different theories. A new relation has been proposed by us for evaluating excess molar volume using ultrasonic velocity of the mixture which gives fairly good result when compared with the experimental values. Excess molar volume has been calculated using Flory's theory and Prigogine–Flory–Patterson theory. The partial molar volume and its excess value at infinite dilution have also been evaluated. 相似文献
98.
《Analytical letters》2012,45(5):1009-1021
Abstract Application of morpholine dithiocarbamate (MDTC) coated Amberlite XAD‐4, for preconcentration of Cu(II), Cd(II), Zn(II), Pb(II), Ni(II) and Mn(II) by solid phase extraction and determination by inductively coupled plasma (ICP) atomic emission spectrometry (AES) was studied. The optimum pH values for quantitative sorption of Cu(II), Cd(II), Zn(II), Pb(II), Ni(II), and Mn(II) were 6.5–8.0, 7.0–8.5, 6.0–8.5, 6.5–8.5, 7.5–9.0, and 8.0–8.5, respectively. The metals were desorbed with 2 mol L?1. The t1/2 values for sorption of metal ions were 2.6, 2.9, 2.5, 2.6, 3.0, and 3.8 min respectively for Cu(II), Cd(II), Zn(II), Pb(II), Ni(II) and Mn(II). The effect of diverse ions on the determination of the previously named metals was studied. Simultaneous enrichment of the six metals was accomplished, and the method was applied for use in the determination of trace metal ions in seawater samples. 相似文献
99.
To monitor the integral dose deposited in the BESⅢ electromagnetic calorimeter whose perfor-mance degrades due to exposure to the BEPCⅡ background, a 400 nm IMPL RadFET dosimeter-based integral dose online monitor system is built. After calibration with the 60Co source and verification with TLD in the pulse radiation fields, an experiment was arranged to measure the BEPC Ⅱ background online. The results are presented. 相似文献
100.