Dextran-graft-poly(hydroxyethyl methacrylate) biosorbents for removal of dyes and metal cations

Dextran-graft-poly(hydroxyethyl methacrylate) gels were prepared and used as a biosorbent for removal of dyes and heavy metal cations. For this propose, the effects of three main parameters during the preparation of gels including concentrations of monomer (hydroxyethyl methacrylate), the crosslinking agent (N,N’-methylenebisacrylamide (MBA)) and initiator (ammonium persulfate) on their swelling and absorbability of dyes and heavy metal cations were investigated. Methylene blue (MB) and rose bengal (RB) as model dyes and Fe(III) and Cu (II) as model metal cations were selected. Increasing the poly(hydroxyethyl methacrylate) content within the gels resulted in higher Equilibrium water absorption (EWA) values and consequently better dye and cation adsorption. Higher concentration of MBA led to lower dye adsorption values. Increasing the ammonium persulfate (APS) concentration did not change significantly the dyes and metal cations adsorption. The results indicated that this biosorbents system could be potentially used in the removal of heavy metal and dye from wastewater. (paper)