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

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.