Abstract:  Chitosan exhibits chelating and adsorption properties for many substances. Through chemicalmodification , various functional groups can be introduced into chitosan molecules, resulting in chitosanderivatives with different properties , thereby broadening the scope of its applications. In this study, acy-lated chitosan cross-linked microspheres were prepared to investigate their adsorption properties for Ni? +Scanning electron microscopy ( SEM) images indicate that the acylated chitosan microspheres have awell-formed spherical structure. The results of the adsorption experiments show that the optimal adsorption of Ni?* occurred under the conditions of pH =7.0 , a contact time of 60 minutes, and an adsorbentdosage of 0. 07 g for a N;?* solution with an initial concentration of 20 mg/L. Thermodynamic studies in-dicate that the adsorption process of Ni?* onto the acylated chitosan cross-linked microspheres is endo-thermic and spontaneous. Kinetic studies reveal that the adsorption process follows a pseudo-second-orderkinetic model ( R’> 0. 99 ). The adsorption process is controlled not only by the physical adsorption ofN;?+ on the internal and external surfaces of the material but also by the chemical adsorption involving ox-ygen-containing functional groups on the surface.

Key words: chitosan: adsorption: thermodynamic parameters : kinetic parameters