Abstract
Abstract The radioactive wastes from different activities have to be safely disposed of and isolated from the human environment. The retardation of radioactive materials by designed barriers is originally controlled by the sorption ability of the mineral compositions. In this work, a naturally available mineral composite, a hydroxyl magnesium silicate (HMS) was investigated as potential natural inorganic sorbent for the retention of long-lived radionuclides ( 134 Cs, 60 Co and 152+154 Eu) from aqueous solutions. The factors affecting the sorption process, such as contact time and pH were evaluated. Furthermore X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential thermal and thermogravimetry analyses (DTA/TGA) measurements were examined in order to assess the physicochemical properties of the magnesium silicate mineral. Langmuir and Freundlich isotherms fitted the result s substantially better than the Flory–Huggins isotherm and the sorption was found to follow pseudo-first order kinetic model. The proposed mineral has been successfully applied for the sorption of 134 Cs, 60 Co and 152+154 Eu radionuclides from real radioactive waste. The results indicated that about 97.4–99% of 134 Cs, 60 Co and 152+154 Eu radionuclides were efficiently retained onto the HMS mineral. Based on the results obtained, it can be concluded that the HMS mineral is an economic and efficient retaining material for environmental hazardous migration and/or leakage of some radionuclides such as 134 Cs, 60 Co and 152+154 Eu and trivalent actinide ( 241 Am, 242m Am and 243 Am) ions. Therefore, this study could be used as a starting point to establish and consider that mineral as an engineered barrier around the disposal facilities at the nuclear activity centres.