A one-pot microwave-assisted synthesis of IPN hydrogels based on HEMA/AM/PVA blend for enhancing Cu(II) and Pb(II) ions removal

Abstract

This study reports the fabrication of an effective adsorbent of poly(2-hydroxyethyl methacrylate-co-acrylamide)/poly(vinyl alcohol) (P(HEMA-co-AM)/PVA) IPN hydrogels synthesized by a one-pot microwave-assisted polymerization, aiming to enhance the Cu(II) and Pb(II) ions adsorption capacity by optimizing the HEMA/AM ratio. The surface morphology and chemical properties of the prepared hydrogels were investigated by using FTIR, SEM, XRD, DSC, TGA, and tensile testing. The influences of hydrogel compositions, pH, temperature, initial metal concentration and contact time on the adsorption of Cu(II) and Pb(II) ions on the IPN hydrogel were evaluated. The maximum water swelling of 1310 % was observed for the 10% HEMA IPN hydrogel. The adsorption of Cu(II) and Pb(II) cations on the IPN hydrogels was well illustrated by the pseudo-first-order adsorption kinetics. The Freundlich adsorption isotherm with the correlation coefficients (R2) of 0.999 well fitted their adsorptions at equilibrium. The maximum amounts of metal uptakes for Cu(II) and Pb (II) on 10% HEMA IPN hydrogel were 200.4 and 292.5 mg/g, respectively. The temperature dependence data also revealed that adsorption process was spontaneous and endothermic. The P(HEMA-co-AM)/PVA IPN hydrogels could be used as an efficient and potential adsorbent for removing heavy metal cations from wastewater.