Adsorption of Zn(II) ions from diluted aqueous solutions by the acrylic copolymer based on ethylacrylate : acrylonitrile : divinylbenzene matrix with different crosslinking degrees and ethylenediamine and triethylenetetramine functional groups was investigated. Adsorption experiments were carried out by batch method. The effects of the pH, initial concentration of zinc, time of contact, and the crosslinking degree of the copolymers were studied. On the basis of Langmuir and Freundlich isotherms, the parameters that characterize the adsorption were determined. The maximum Zn(II) retention capacity value (500 mg g Ϫ1 ) was obtained for the acrylic copolymer with 2% crosslinking degree and ethylenediamine, as functional groups.
A weak acid acrylic resin was used as an adsorbent for the investigation of Basic Blue 3 (BB3) adsorption kinetics, isotherms, and thermodynamic parameters. Batch adsorption studies were carried out to evaluate the effect of pH, contact time, initial concentration (28-100 mg/ g), adsorbent dose (0.05-0.3 g), and temperature (290-323 K) on the removal of BB3. The adsorption equilibrium data were analyzed by the Langmuir, Temkin, and Freundlich isotherm models, with the best fitting being the first one. The adsorption capacity (Q o ) increased with increasing initial dye concentration, adsorbent dose, and temperature; the highest maximum Q o (59.53 mg/g) was obtained at 323 K. Pseudo-first-order and pseudo-second-order kinetic models and intraparticle diffusion models were used to analyze the kinetic data; good agreement between the experimental and calculated amounts of dye adsorbed at equilibrium were obtained for the pseudo-second-order kinetic models for the entire investigated concentrations domain. Various thermodynamic parameters, such as standard enthalpy of adsorption (DH o ¼ 88.817 kJ/mol), standard entropy of adsorption (DS o ¼ 0.307 kJ mol À1 K À1 ), and Gibbs free energy (DG o < 0, for all temperatures investigated), were evaluated and revealed that the adsorption process was endothermic and favorable.
Abstract:The sorption capacity of three weak base ion exchangers based on acrylic copolymers functionalized with ethylenediamine, triethylenetetramine and N, N-dimethylamino propylamine for Ag(I) ions was evaluated. Adsorption experiments were carried out by batch method. The effect of pH, crosslinking degree of copolymers, amount of sorbent, initial ion concentration, contact time and temperature was studied. The parameters which characterize the retention process were estimated using Langmuir and Freundlich isotherm models, the best fitting being for the first model. Kinetic data were fitted to pseudo-first order, pseudo-second order and intraparticle diffusion models. Experimental data were in good agreement with the pseudo second order.
Using the batch method, the retention of Ga(III) from HCl solutions by two gel-type pyridine strongbase anion exchangers containing 1-methyl-or 1-butyl-4-vinylpyridinium chloride structural units, called S 1 and S 2 resins, respectively, was studied. The influence of the HCl and Ga(III) concentrations as well as of the contact time between the resin and the liquid phase was investigated. The parameters, which characterize the retention process, were estimated using Langmuir and Freundlich isotherms. Both resins exhibited a higher affinity for gallium ions from a 6M HCl solution. According to Langmuir isotherms, maximum retention capacities of 44.44 and 60 mg Ga(III)/g dry resin for the S 1 and S 2 resins, respectively, were obtained. Freundlich isotherms provide additional proof for a higher affinity of the S 2 resin for Ga(III) from HCl solutions. It is clear that the substituent length increase on N ϩ atoms led to an increasing affinity of the pyridine strong base anion exchangers toward Ga(III).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.