Synthesis and application of a new chitosan derivative for adsorption of Cu(II) and oxyanions of Cr(VI) from aqueous solution

This study describes the synthesis of a new bioadsorbent from chitosan using ethylenediaminetetraacetic dianhydride (EDTAD) as modifying agent and its successful aplication for removal of cationic ion (Cu(II)) and oxyanion (Cr(VI)) from single component aqueous systems. The new multifunctionalized chitosan derivative (C1) was produced through chemical modification of primary hydroxyl function of chitosan with EDTAD to introduce carboxylic and tertiary amine functional groups, maintaining the secondary amines on the chitosan surface. Such a transformation was important to increase the adsorptive potential of chitosan but also to allow C1 to be used in acidic media, thus solving the problem of solubility of most chitosan derivatives. C1 was characterized by spectroscopic methods. The effects of solution pH, contact time, and initial solute concentration on removal of Cu(II) and Cr(VI) by C1 were investigated in aqueous solutions. C1 showed experimental maximum adsorption capacity of 106 mg g−1 for Cu(II) and 194 mg g−1 for Cr(VI).