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Recovery of uranium from UCF liquid waste by anion exchange resin CG-400: Breakthrough curves, elution behavior and modeling studies
, Article Annals of Nuclear Energy ; Volume 54 , April , 2013 , Pages 149-153 ; 03064549 (ISSN) ; Sepehrian, H ; Semnani, F ; Samadfam, M ; Sharif University of Technology
2013
Abstract
Continuous fixed-bed column studies were carried out by using Amberlite CG-400 anion exchange resin for the recovery of uranium from aqueous solutions (synthetic solutions and uranium conversion facility (UCF) liquid waste). Effects of operating parameters such as flow rate and bed height were studied. The breakthrough capacity decreases with increasing flow rate, but this dependence was not significant with a long column. The maximum breakthrough capacity of uranium ions were achieved by CG-400 resin at a flow rate of 0.2 mL min-1 and bed height 9.1 cm (4 g resin). The elution behavior of uranium from CG-400 resin by various eluents have been investigated and the results show that 0.5 mol...
Adsorptive behavior of an amberlite anion exchanger resin for uranium (VI) sorption in the presence of sulfate anions
, Article International Journal of Engineering, Transactions B: Applications ; Volume 29, Issue 2 , 2016 , Pages 170-175 ; 1728144X (ISSN) ; Sepehrian, H ; Fasihi, J ; Arabieh, M ; Mahani, M ; Sharif University of Technology
Materials and Energy Research Center
Abstract
Uranium (VI) sorption using an anionic exchanger resin, namely Amberlite IRA910, in the presence of sulfate anions was the subject of current study. Batch sorption experiments were carried out to evaluate the influence of operational parameters such as pH, contact time, initial concentration and existence of various anions (including phosphate, sulfate, chloride, fluoride, and nitrate) in the solution on Amberlite IRA910 sorption behavior. Experiments revealed that uranium adsorption was fulfiled at pH>3 and 50 min to amount of 80%. Kinetics study revealed that the pseudo-second-order model showed better curve-fitting regression of the experimental data than the pseudo-first-order one....
Investigation on various types of ion-exchange membranes in vanadium redox flow batteries: Experiment and modeling
, Article Journal of Energy Storage ; Volume 54 , 2022 ; 2352152X (ISSN) ; Rahimi, M ; Molaei Dehkordi, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Choosing the appropriate ion exchange membrane in vanadium redox flow batteries plays an important role in achieving optimal system performance. In this article, the implementation of commercial cation exchange membranes (Nafion 115, Nafion 117, and Nafion 212), anion exchange membranes (FAP 450 and QA-PFE), and the combination of them are investigated. In this regard, the effects of membrane type, thickness, electrical conductivity, and the transfer of vanadium species at different current densities are examined carefully. In addition, the influences of the flow rate and the concentration of electrolytes are investigated using a comprehensive developed model. The model predictions are...
Preparation of Polymeric Ion-Exchange Membrane for Water Desalination
, M.Sc. Thesis Sharif University of Technology ; Musavi, Abbas (Supervisor)
Abstract
In present research work, methods of preparing ion exchange membranes, especially anion exchange membranes, were studied and chemical modification of polysulfone was chosen as a safe and economical method for preparing anion exchange membranes. The chloromethylated polysulfone was characterized by HNMR spectroscopy and functionalization degree was determined according to peak area integration. Membranes were produced by mixing and amination of the chloromethylated and normal polysulfone (40-100% wt). Morphology and chemical structure of membranes were investigated by SEM images and FTIR spectroscopy.The ionic conductivity, ion exchange capacity and water content of samples were measured. The...
Visible light photocatalytic performance of Ag2O/ZnCr-LDH nanocomposite
, Article Chemical Physics Letters ; Volume 751 , 2020 ; Rasteh, M ; Gholami, M. R ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Ag2O particles were loaded on the surface of ZnCr-LDH via an anion-exchange precipitation approach by using privilege of the memory trace feature of the LDH-type materials. The structural properties of the resulted photocatalyst were explored by different spectroscopic and microscopic methods. The photocatalytic studies on acid black degradation ascertained that the prepared Ag2O/ZnCr-LDH nanocomposite represented an observably increased degradation performance of organic pollutants compared with pure Ag2O and ZnCr-LDH. This improved photocatalytic performance can be ascribed to the enhanced surface area, good order distributing of particles and effective charge carrier transfer and...
Uranium(VI) sorption behavior onto amberlite CG-400 anion exchange resin: Effects of pH, contact time, temperature and presence of phosphate
, Article Annals of Nuclear Energy ; Volume 48 , October , 2012 , Pages 21-24 ; 03064549 (ISSN) ; Asadi, Z ; Samadfam, M ; Sepehrian, H ; Sharif University of Technology
Elsevier
2012
Abstract
In this paper, uranium sorption onto amberlite CG-400 anion exchange resin in the presence of phosphate anions was studied. The effect of contact time between the sorbent and aqueous solution, pH, initial concentration of uranium and temperature were also investigated. Kinetic studies show that uranium sorption onto amberlite CG-400 resin in the presence of phosphate is a fast process and follows pesudo-second-order kinetics. It was also found that the pH value and the presence of phosphate play very important roles in the uranium sorption onto CG-400 resin. Optimum pH for uranium sorption in the presence of phosphate anions was about 3.5. The experimental sorption isotherm is successfully...
Polymeric ionic liquid nanogel-anchored tungstate anions: A robust catalytic system for oxidation of sulfides to sulfoxides
, Article New Journal of Chemistry ; Volume 39, Issue 2 , 2015 , Pages 1348-1354 ; 11440546 (ISSN) ; Nazari Chamazkoti, M ; Hosseini, S. H ; Sharif University of Technology
Abstract
A new heterogeneous catalytic system was prepared by immobilization of tungstate ions on a cross-linked poly(ionic liquid) nanogel. The solid nanogel was easily synthesized by a surfactant-less method. The resulting catalyst was highly active in selective oxidation of sulfides to sulfoxides by H2O2. The oxidation reactions were successfully performed under solvent-free conditions affording high yields. The catalyst was recycled and reused for several reaction cycles without any significant loss of catalytic activity