ABSTRACT:The sorption behavior of Th(IV) and U(VI) species on two batch molds of radiation-induced polymerized unsaturated polyester beads containing 40 wt % styrene was investigated. The distribution coefficients of both ions on the polymeric sorbents were evaluated at 30°C using 10
Ϫ4M solution and found to be 271.9 and 469.8 mL/g on the first mold and 296 and 1189.2 mL/g on the second mold for Th(VI) and U(IV), respectively. Testing the sorption data using different theories provided evidence that the sorption data accurately fit the Langmuir, Freundlich, and D-R isotherms, indicating chemisorption occurred and that E, the mean sorption energy of thorium and uranium on the different molds of unsaturated polyester-styrene, was between 8.304 and 13.92 kJ/mol, reflecting the nature of the ion exchange. The thermodynamics of sorption were considered in order to evaluate ⌬H, ⌬S, and ⌬G. The data showed that the sorption process was spontaneous and exothermic.
Functionalized membranes were obtained by radiation-induced graft copolymerization (RIGP) of acrylamide-acrylic acid (AAm-AAc) and acrylamide-4-vinyl pyridine (AAm-4VP) binary monomers on both low-density polyethylene and polypropylene films. The supporting conditions as inhibitor concentration, irradiation dose comonomer compositions and concentrations were studied and optimized. The prepared membranes were characterized using SEM, DTA-TG, and FTIR. They proved that supporting the selected hydrogels on the base films have modified their structure and enhanced their thermal and mechanical characteristics. The sorption characteristics of Th(IV) and U(VI) on the different membranes were studied. The amount of ions sorbed at equilibrium was found to increase with increase in the degree of graft at certain conditions. The kinetics of sorption was also studied and found to obey the Lagergren and Morris-Weber kinetic models.
Superfast kinetics of Nd þ3 , Eu þ3 , and Gd þ3 ions were studied on the surfaces of N, N, N \ , N \ -tetramethylmalonamide (TMMA) and silsesquioxane resins. TMMA and SSQXN-8 were prepared by suspension polymerization and sol-gel routes, respectively. They were identified using elemental analysis, FTIR, H-NMR, 13 C-NMR, MIP, and BET surface area. Kinetic investigations were performed in batch conditions and different models were used to fit the data; Boyd and Helfferich models were found the best. The diffusion of the ions through the resins were very fast and found to be in the order of 10 À16 m 2 /S. Effective diffusions of the studied ions were found to be 10 À15 order of magnitude and directly proportional to the kinetic energy of the transition state. DS* values from À166.044 to À179.297 J mol À1 K À1 were estimated as entropy stability factors of the system.
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