Gelatin-based mesoporous hybrid materials for Hg2+ ions removal from aqueous solutions

Abstract

High toxicity and bioaccumulation are the two major features that make mercury as the most dangerous heavy metal for the living organisms and mandates its removal from the contaminated water bodies. Keeping this in view, a new gelatin-based mesoporous hybrid material, with SiO2 as the inorganic and gelatin as the biopolymeric component, was synthesized via the sol-gel process. The material was characterized by FTIR, SEM, SEM-EDS, TEM and BET studies. The synthesized hybrid material containing Gelatin/SiO2, has high surface area of 675.92 m2 g−1. It was evaluated as an adsorbent of Hg2+ ions from their aqueous solutions. Parametric study of the factors affecting adsorption process was carried out to find the optimum adsorption conditions. Different kinetic and isotherms models were applied to the data obtained and adsorption was found to follow pseudo-second order kinetics and Langmuir isotherm model. The highest partition coefficient value of 7.13 mg g−1 µM−1 was obtained at the lowest initial Hg2+ ions concentration (50 ppm) studied alongwith an adsorption capacity of 43.85 mg/g while for the highest initial concentration of 225 ppm the respective values were 0.876 mg g−1 µM−1 and 105.075 mg/g. Cumulative adsorption capacity of the hybrid material from reusability studies in seven cycles was found to be 315.6 mg g−1.