Novel Functional Polymer Sorbent for Adsorption of Uranyl Ions from Aqueous Solutions

Maleic anhydride-heptene-1-styrene terpolymer has been synthesized andmodified with allyl alcohol and methylmethacrylate in order to prepare a newcross-linked functional polymer sorbent. The synthesized terpolymer, monoallylester of terpolymer and synthesized cross-linked sorbent were characterized byFourier transform infrared and 1H NMR spectroscopies. The synthesized cross-linkedpolymer sorbent has a network structure and contains carboxylic acid, carbonyl andester groups, all of which are capable of interacting with metal ions. The sorptionperformance of uranyl ions under optimum sorption conditions was evaluated. Theanalytical characteristics of the sorbent, such as, the solution pH, sorption degree andsorption capacity, have been established and the optimum sorption conditions havebeen determined. The sorption degree reaches a maximum at pH 6 (73.5%) and themaximum experimental sorption capacity of the sorbent for uranyl ions has beenestimated as 1.8 mmol.g^-1 (486 mg.g^-1). Sorption isotherms of uranyl ions ontoprepared polymer sorbent have been measured and the equilibrium data have fittedwell to the Langmuir and Freundlich isotherm models. Langmuir and Freundlichisotherm constants and correlation coefficients for the present system are calculatedand compared. The obtained values of the Langmuir and Freundlich equationsparameters (qmax = 2.03 mmol.g^-1, KL = 2.56, KF = 1.33, n = 2.35) specify a sufficientlyhigh sorption activity of the synthesized sorbent towards uranyl ions. Uranyl ions aredesorbed from the sorbent by treatment with 20-25% hydrochloric and nitric acids.