Removal of ¹³⁴Cs and ^152+154Eu from liquid radioactive waste using Dowex HCR-S/S

Abstract

Radionuclides should be separated from the waste streams before their discharge due to their undesired effects on human physiology and ecological systems. In this work, the feasibility of using Dowex-HCR-S/S(HCR), a strong acid cation-exchange resin as sorbent for ¹³⁴Cs and ^152+154Eu ions removal was examined. Sorption experimental data were analyzed by kinetic and isotherm models. The distribution coefficients of ¹³⁴Cs and ^152+154Eu were studied as a function of pH; 3525.6 mL/g and 393.1 mL/g were obtained in case of ^152+154Eu and ¹³⁴Cs at pH 4.1, respectively. Four isotherm models; Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich, were used to fit the sorption equilibrium data. The results indicated that the sorption of both ¹³⁴Cs and ^152+154Eu onto HCR resin is highly fit with the pseudo-second order model. The sorption kinetic for ¹³⁴Cs and ^152+154Eu onto polymeric resin takes 90 and 120 min to reach equilibrium which is considered as a fast kinetic process. The results of sorption experiments indicate that the maximum sorption capacity of ¹³⁴Cs and ^152+154Eu are 102.84 and 161.93 mg/g. The amount of radionuclides removed increased with increasing temperature, which indicates the endothermic nature of the sorption process. The negative values of ΔG^○ indicated the spontaneity of the sorption process. The proposed procedure has been successfully applied for the removal of ¹³⁴Cs, ^152+154Eu and other radionuclides from real liquid radioactive waste. The present study concludes that the commercial HCR resin used under these conditions, has a considerable potential as an effective sorbent for the removal of ¹³⁴Cs and ^152+154Eu from real radioactive wastewater. It can therefore have a place in the treatment of cationic radionuclides from radioactive wastewater since it is of a low-cost and commercially available adsorbent.