An in situ reactive spray-drying strategy for facile preparation of starch-chitosan based hydrogel microspheres for water treatment application

Hydrogel microspheres (HMs) were prepared from hydroxyethyl starch and carboxymethyl chitosan via in situ reactive spray drying, using epichlorohydrin as the crosslinking agent. SEM characterization showed the HMs were spherical and collapsed structures. The swelling behavior and adsorption performance of the HMs were studied systematically. The experimental results demonstrated that HMs possessed pH and salt sensitiveness and the maximum adsorption capacities of HMs for methylene blue, Eosin Y, Cd 2+ , Cu 2+ , and Ni 2+ were 106.97 mg/g, 143.55 mg/g, 32.51 mg/g, 47.87 mg/g, and 27.18 mg/g, respectively. Further study indicated that the adsorption isotherms and kinetics were respectively fitted with the Langmuir isotherm model and the pseudo-second-order model. In view of the advantages of in situ reactive spray drying for the preparation of novel pH- and salt- responsive HMs, the strategy presented here has a great application potential in wastewater treatment.