Cross-linked chitosan microspheres entrapping silver chloride via the improved emulsion technology for iodide ion adsorption

Abstract

Radioactive iodine waste from nuclear plant became the severe environmental problem and led to the public health concern. The cross-linked chitosan adsorbed iodide anions through the electrical attraction, yet performing limited-efficiently. Targeting as the better adsorption, the modified chitosan sorbent as AgCl@CM (silver chloride entrapped in the cross-linked chitosan microspheres) for iodine adsorption was proposed and implemented by chemisorption from AgCl and physisorption from chitosan via the improved emulsion method (emulsions mixing-collision and polymerization). With the broad application from pH 2 to pH 10, the spherical AgCl@CM (from 0.20 g silver nitrate) performed the I127 anions (instead of radioactive iodine) adsorption efficiency of higher than 90 % in 20 min, with the maximum adsorption capacity of 1.5267 mmol/g, well-fitting with the pseudo-first-order model and Sips isothermal model. AgCl@CM also performed I127 adsorption with the significant selectivity relative to Cl−. The micro-spherical AgCl@CM sorbents were therefore prospective-effectively for iodine waste water treatment.