Adsorption of UO2 2+ on poly(N,N-diethylacrylamide-co-acrylic acid): effects of pH, ionic strength, initial uranyl concentration, and temperature

We prepared poly(N,N-diethylacrylamide-co-acrylic acid) (P(DEA-co-AA)) microgels which could efficiently remove UO₂ ²⁺ from aqueous solutions. In this study, the effect of adsorption parameters such as pH value, adsorbent dose, shaking time, and temperature has investigated. It is found that the pseudo-second-order model is more suitable for our experiment. The adsorption kinetic data indicated that the chemical adsorption was the swiftness processes, the adsorption equilibrium could be achieved within 30 min. And there are very good correlation coefficients of linearized equations for Langmuir isotherm model, which indicated that the sorption isotherm of the hydrogel for UO₂ ²⁺ can be fitted to the Langmuir isotherm model. The adsorption process was spontaneous (?G ⁰ < 0) and exothermic (?H ⁰ < 0). The adsorbed UO₂ ²⁺ can be desorbed effectively by 0.1 M HNO₃ and the adsorption capacity is not significantly reduced after five cycles. Present study suggests that this P(DEA-co-AA) can be used as a potential adsorbent for sorption UO₂ ²⁺ and also provide a simple, fast separation method for removal of UO₂ ²⁺ ions from aqueous solution.