A new bifunctionalized chitosan (C2) with zwitterionic characteristics was prepared.
Trimethylation of amine and esterification of hydroxyls with EDTAD was performed.
C2 was used for the adsorption of Cu2+, Co2+, Ni2+, and Cr6+ in aqueous solutions.
Qmax of C2 for Cu2+, Co2+, Ni2+, and Cr6+ were 0.698, 1.125, 0.725, and 1.91 mmol/g.
Desorption (0.1 mol/L HNO3) and reusability of the C2 adsorbent was also evaluated.