Hydrazinolyzed cellulose-g-polymethyl acrylate as adsorbent for efficient removal of Cu(II) and Ni(II) ions from aqueous solution

Abstract

BACKGROUND Although methyl acrylate has been graft polymerized from cellulose and functionalized with hydrazine and hydroxylamine for removal of copper and nickel ions, the adsorption capacity was less than 80 mg g−1. The present work reported hydrazinolysis of cellulose-graft-polymethyl acrylate and remarkably improved adsorption capacity for Cu(II) and Ni(II) in aqueous solution. RESULTS Hydrazinolyzed cellulose-graft-polymethyl acrylate (Cell-g-PMA-HZ) has been prepared by ceric salt-initiated graft polymerization of methyl acrylate from microcrystalline cellulose surface and subsequent hydrazinolysis with hydrazine hydrate. The successful synthesis was confirmed by Fourier-transform infrared spectroscopy, 13C-NMR, elemental analysis, scanning electron microscopy and thermogravimetric analysis. Adsorption behavior of Cell-g-PMA-HZ for Cu(II) and Ni(II) were studied through batch static adsorption processes and column chromatography methods. The influences of graft yield, initial pH, contact time and temperature on adsorption capacity of Cell-g-PMA-HZ as well as adsorption equilibrium, kinetic and thermodynamic properties were studied in detail. Kinetic adsorption can be explained by pseudo-second-order and adsorption isotherms fitted with Langmuir isotherm model, from which maximum equilibrium adsorption capacity can be derived as 229.36 mg g−1 for Cu(II) and 173.91mg g−1 for Ni(II) at 28°C. Further thermodynamic investigation indicated that adsorption of Cu(II) and Ni(II) by adsorbent Cell-g-PMA-HZ was exothermic and spontaneous under the studied conditions. CONCLUSIONS Hydrazinolysis of cellulose-graft-polymethyl acrylate has been accomplished. As an adsorbent, the prepared Cell-g-PMA-HZ was reusable and fairly efficient for removal of Cu(II) and Ni(II) from aqueous solution. © 2015 Society of Chemical Industry