Copolymerization of ethyl acrylate onto guar gum for the adsorption of Mg(II) and Ca(II) ions

Abstract

In the present study, the copolymerization of ethyl acrylate and guar gum was induced by microwave irradiation in the presence of catalytic amount of the initiator potassium persulfate (KPS). The maximum percentage conversion was found to be 107.1% under microwave power of 900 MW after 3 min exposure. The copolymerized guar gum-graft-poly-ethyl acrylate (GG-g-PEA) was characterized using FTIR spectroscopy and SEM analysis. The effect of pH on the capacity of the GG-g-PEA copolymers to reduce the hardness of the water was investigated, leading to the effective removal of Ca(II) and Mg(II) ions from solutions at pH 8. The calculated values of the coefficient of determination (0.914–0.9553) for Ca(II) and Mg(II), respectively, showed that the equilibrium isotherm data followed the Freundlich isotherm model. The pseudo-second-order model was suitable for the modelling of the kinetic data, predicting adsorption capacities of 0.2680 g/mg/min for Ca(II) and 0.3835 g/mg/min for Mg(II), respectively. The synthesized GG-g-PEA adsorbent could therefore be recommended for the reduction in the water’s hardness