A functionalized chitosan wrinkled hollow sphere containing calcium ions: Efficient adsorption of sodium...

In this study, a novel chitosan material (ECS@Ca@CTA) was prepared to significantly adsorb sodium dodecylbenzene sulfonate (SDBS). First, chitosan is complexed with CaCl₂ and crosslinked into hollow spheres by glutaraldehyde (GA). However, a part of the active groups (amino group) is depleted. The amino group is crucial in CS, which can adsorb anions under acidic aqueous solutions and be functionalized by other groups. Therefore, the amino group is reactivated by ethylenediamine (EDA), then the ECS@Ca is quaternized by (3-chloro-2 hydroxypropyl) trimethylammonium chloride (CTA) and prepared to hollow sphere structure with wrinkled surface in order to improve the effect of pH on adsorption of SDBS. It is not only a simple functionalization, but a synergistic effect between the three materials (ECS@Ca@CTA) to efficiently adsorb SDBS. Thus the maximum adsorption capability of ECS@Ca@CTA is 2430, 1967 and 1116 mg g^-1 at pH 3.0, 7.0 and 10.0 for SDBS, respectively. The adsorption kinetics, adsorption isotherm and reusability of ECS@Ca@CTA were studied. This paper is to provide a new environmentally friendly adsorbent material to adsorb SDBS.