Sorption of some radionuclides from liquid waste solutions using anionic clay hydrotalcite sorbent

Abstract

129I and 79Se are potentially important anionic radionuclides in safety assessments due to their high mobility, radiotoxicity, and long half life's (1.7 × 107 and 3.27 × 105 years, respectively). This study is interested in the sorption of 131I and 75Se radionuclides onto magnesium iron hydrotalcite (Mg/Fe HTlc). Mg/Fe HTlc was prepared by co-precipitation technique and characterized using different analytical tools such as FT-IR, XRD, XRF, TGA & DTA, SEM, and BET. Results obtained from this study showed that the adsorption process was a very fast equilibrium time (20 min). The distribution coefficient values as a function of pH have high separation factors for 131I at all different pHs. Reaction kinetic obeys the pseudo-second-order model. Maximum sorption capacity for 131I and 75Se has the values 21.45, and 9.25 mg/g respectively. Sorption isotherms are more relevant to a Langmuir isotherm. The % removal of 131I is decreased by increasing the concentration of competing species. The investigation evidenced that the prepared sorbent is suitable for the removal of 131I and 75Se from radioactive waste and could be considered potential material for purification of effluent polluted with these radionuclides.