The highly effective removal of Cs+ by low turbidity chitosan-grafted magnetic bentonite

Abstract

Chitosan-grafted magnetic bentonite (CS-g-MB) was successfully synthesized via a plasma-induced method. The CS-g-MB composite shows good magnetic properties, low turbidity, and high stability in aqueous solution and exhibits significant adsorption capacity for Cs+ ions. The adsorption of Cs+ by CS-g-MB is dependent on both pH and ionic strength. In the presence of Mg2+, K+, Li+, and Na+ ions, the Cs+ exchange is constrained in the order of Li+≈Mg2+<Na+<K+, primarily as a result of the hydrated radii and hydration energies of these cations in aqueous solution. The stability of the CS-g-MB composite in simulated groundwater and in actual seawater was also investigated and this material was found to be a good candidate for the remediation of both types of water. These results demonstrate that enhanced coagulation achieved by plasma modification represents a viable yet advanced technology for wastewater management, and is capable of synthesizing new adsorbents that can be readily separated from solution and that avoid increasing the turbidity and color of the water being treated.