Removal of selenium and iodine radionuclides from waste solutions using synthetic inorganic ion exchanger

Abstract

79Se and 129I are potentially important anionic radionuclides in safety assessments due to its radiotoxicity, high mobility and long half life's (3.27×105 and 1.7×107years, respectively). This study has examined the sorption potential of synthetic microporous inorganic exchanger for 75Se (t1/2 120days) and 125I (t1/2 60.2days), as a surrogate for 79Se and 129I. The exchanger was synthesized by sol–gel method and characterized using scanning electron microscope (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD); nitrogen physisorption measurements (BET), Fourier transform infrared spectroscopy (FTIR) and finally thermal analysis. Batch mode sorption was completed to estimate the effects of the system variables. Kinetic models were applied to check the sorption rate data. The equilibrium sorption results obtained were also tested using isotherm models. The monolayer capacity (Qmax) values are 43.5 and 62.5mg/g for 75Se and 125I, respectively. Sorptive removal of 75Se and 125I from contaminated tap water and environmental water samples approved the legality of the results acquired in these batch mode studies. The results showed, in a situation of emission of anionic radionuclides to the natural environment the synthetic inorganic exchanger could act as a succeeded and economical adsorbent for retention of different anionic radionuclides such as 79Se, 129I, 36Cl and 99Tc.