New hydrogels based on modified chitosan as metal biosorbent agents.

In this study, two new green biodegradable hydrogels (A1, A2) based on modified chitosan by dialdehydes were prepared via reaction of chitosan with [4,4'-diformyl-α-ω-diphenoxy-ethane or 4,4'-diformyl-2,2'-dimethoxy-α-ω-diphenoxy-ethane] under different reaction conditions. Characterization techniques were applied to the prepared hydrogels as FTIR, TGA, SEM, and X-ray. The efficiency of adsorption of Cu (II), Co (II), Zn (II), Hg (II) and Pb (II) ions from aqueous solution under different pH values were investigated. The results revealed that these hydrogels showed pH sensitive behavior in metal removal. Hydrogel (A2) showed the highest adsorption of Hg (II) ion at pH 5.