AloeVera as an effective biosorbent for the removal of thorium and barium from aqueous solutions

The use of three biosorbents based on AloeVera wastes for the removal of thorium and barium from aqueous solutions (Cinit: 5–200 mg L−1, pH 3 and 5) was investigated using radiochemical and spectroscopic techniques. The biosorbents (raw and modified materials by acidic and alkaline reagents) were characterized before and after sorption by SEM, XRD and FTIR. The alkaline modified materials exhibited significant removal efficiency (170 and 107.5 mg g−1 for thorium and barium, respectively). The equilibrium data were fitted by Langmuir and Freundlich models whereas leaching and desorption tests were also performed. Furthermore kinetics and thermodynamic data indicate a complex mechanism involving mainly physical sorption and surface precipitation.