Isotherm, Kinetic, and Selectivity Studies for the Removal of 133Ba and 137Cs from Aqueous Solution Using Turkish Perlite

Abstract

The efficiency of 133Ba and  137Cs removal from aqueous solution is vital to mitigate ecological concerns over spreading these radionuclides in the environment. The present work focused on the use of Turkish perlite for the sorptive removal of  133Ba and  137Cs from aqueous solution by the radioindicator method. Perlite was characterized by XRF, XRD, FTIR, SEM–EDX, and BET analyses. The maximum percentage removals of 88.2% and 78.7% were obtained for  133Ba and  137Cs at pH 6 and pH 9, respectively. For both ions, the sorption equilibrium was attained relatively rapidly. Experimental kinetic data were well described with pseudo-second-order and intraparticle diffusion models. The uptake of both ions increased with the increase in metal concentration (1 × 10−5 to 5 × 10−2 mol/L) in solution. The maximum uptake capacities of  133Ba and  137Cs were found to be 1.96 and 2.11 mmol/g, respectively. The effect of competing ions decreased in the order of Ca2+>K+>Ni2+>Na+ for  133Ba sorption, whereas for  137Cs sorption, the order was determined as Ca2+>Ni2+>K+>Na+. Selectivity studies pointed out that sorption of  133Ba onto perlite is preferable to  137Cs. Therefore, Turkish perlite is a promising, cost-effective, and efficient natural material for the removal of  133Ba and  137Cs from relatively diluted aqueous solution.