Development and evaluation of thiosalicylic-modified/ion-imprinted chitosan for selective removal of cerium (III) ion

Chitosan was used in this study as the bio-based product for the development of microparticles for the specifically targeted removal of cerium ions (Ce ) by ion-imprinting technology. A thiosalicylic hydrazide-modified chitosan (TSCS) is produced via cyanoacetylation of chitosan, followed by hydrazidine derivatization to finally introduce the thiosalicylate chelating units. Ion-imprinted Ce-TSCS sorbent microparticles were prepared by combining the synthesized TSCS with Ce , crosslinking the polymeric Ce /TSCS complex with glutaraldehyde, and releasing the chelated Ce using an eluent solution containing a mixture of EDTA and HNO . Ce-TSCS had a capacity of 164 ± 1 mg/g and better removal selectivity for Ce because it was smart enough to figure out which target ions would fit into the holes made by Ce during the imprinting process. The kinetic data were well suited to a pseudo-second-order model, and the isotherms were well described by the Langmuir model, both of which pointed to chemisorption and adsorption through Ce chelation. XPS and FTIR analyses demonstrate that the predominant adsorption mechanism is the coordination of Ce with the -NH-, -NH , and -SH chelating units of the thiosalicylic hydrazidine. These findings provide fresh direction for the development of sorbent materials that can effectively and selectively remove Ce from aqueous effluents.