Preparation of Biopolymeric Microcapsules and Their Uptake Properties for the Heavy Metal Ions

Abstract

An organic extractant, Cyanex 302, having a relatively high selectivity toward the soft metal ions, was microencapsulated in the alginate biopolymer matrices. Various shapes of microcapsules such as granule, fiber and film were prepared by contacting a kneaded sol of HA and sodium alginate with a gelling solution. The uptake of Cd²⁺ for microcapsules attained equilibrium within 20 h, and Cd²⁺ ions were selectively adsorbed on microcapsules even in the presence of 0.1 M HNO₃ or 1 M NaNO₃. The uptake (%) of other heavy metal ions, Ag, Pb, Cu and Zn on microcapsules was above 96%, suggesting a possibility of simultaneous removal of soft metal ions. The uptake ability of Cd²⁺ for microcapsules was superior to that for conventional adsorbents in the presence of 0.1M HNO₃. The column packed with granular microcapsules was effective for the successive removal of Cd²⁺ ions.