LAUSR

The magnetic chitosan nano-particles functionalized with alanine (or valine) were prepared for enhancing Th(IV) sorption. The uptake kinetics followed the pseudo-second-order model whilst the sorption isotherms fitted to the Langmuir model. The maximum Th(IV) sorption capacities are 128.7 and 154.0 mg/g for MCN-Val and MCN-Ala sorbents, respectively. MCN-Ala has higher Th(IV) sorption capacity since it contains more sorption sites (amino and carboxylic groups) and has less steric hindrance. The values of thermodynamic parameters indicate that Th(IV) sorption is endothermic and spontaneous. The fast kinetics and magnetic properties of the nano-sorbents allow their efficient Th(IV) sorption and magnetic separation from the solution.