Selective adsorption of trivalent metal ions from multielement solution by using gamma radiation-induced pectin-acrylamide-(2-Acrylamido-2-methyl-1-propanesulfonic acid) hydrogel

Abstract

The present research is focused on the selective adsorption of trivalent metal ions from multielement solution by using functional hydrogel. The hydrogels were synthesized from the aqueous blend of Pectin, Acrylamide (AAm) and 2-Acrylamido-2-methyl-1-propanesulfonic acid (AMPS) by applying gamma radiation. The results of gel fraction and equilibrium swelling optimized 1:2:3 ratio of raw materials (pectin, AAm, and AMPS) and 2 kGy radiation dose for the preparation of hydrogels. The functional groups of the hydrogel were confirmed by Fourier transform infrared (FTIR) spectroscopy. The thermal properties were studied by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) was used to analyze the surface morphology of hydrogels before and after metal adsorption. Hydrogels were applied to selective adsorption of five elements (Al, Cr, Fe, Ga, and In) from the multielement solution as well as adsorption from the manually prepared solution of five elements. The effect of pH on the adsorption capacity of hydrogel was examined. The adsorption data was used to study the adsorption isotherm models where the Freundlich adsorption isotherm model was found to be well fitted compared to the Langmuir adsorption isotherm model. From the Freundlich isotherm model, the maximum adsorption capacities of Al, Cr, Fe, Ga and In were found to be 11.34, 11.52, 11.92, 11.57 and 17.73 mg/g of gel respectively. Desorption efficiency was found to be about 80%. The research results suggest that the hydrogel can effectively be used for the recovery of above mentioned trivalent metal ions.