Preparation of hybrid β-chitosan - squid pen protein hydrogel beads by ionic liquid regeneration for adsorption of copper(II) and zinc(II) from wastewater.

This study explores the use of squid pen protein to enhance the chemical stability and heavy metal ion (Cu and Zn) affinity of β-chitosan. Hydrogel beads with enhanced porosity and scalability were prepared using 1-butyl-3-methylimidazolium acetate, ([BMIM][OAc]), which simultaneously functionalized β-chitosan by decreasing its crystallinity and enhancing binding site access, as indicated by Fourier transform infrared (FT-IR) spectroscopy, which revealed intensification of functional group expression. Notably, this functionalization compensated for the effects of glutaraldehyde crosslinking.