Preparation and investigation on the adsorption behavior of polyethylene glycol modified sodium alginate porous membrane adsorbent for Cr(III) ions

In this study, sodium alginate based porous membrane adsorbents(GA/SA) were prepared by using polyethylene glycol(PEG) as porogen and glutaraldehyde(GA) as cross-linking agent. The prepared GA/SA were used to remove Cr(III) ions from wastewater to test its adsorption performance. The proposed technique is very convenient for operation. The batch experiments were performed to investigate the adsorption kinetics of Cr(III) ions from aqueous solution under different conditions, such as the amount of PEG in the GA/SA, pH of solution, initial Cr(III) ions concentration, adsorbent dose and contact time. The GA/SA exhibited the maximum uptake capacity of 57.4 mg/g under the optimal condition. The experiment results show that the adsorption is high pH-dependent. Various kinetic models were applied to examine the mechanism of adsorption processes. Pseudo-second-order kinetic model exhibits the best correlation with experimental data. The kinetic experiment results show that the adsorption of Cr(III) ions is a multistep limited adsorption process. Out of Langmuir and Freundlich isotherm equations, the batch equilibrium data are better described by the Freundlich isotherm equation. The prepared GA/SA could be considered as a potential low-cost and high-effective bio-sorbent for removing and recovering Cr(III) ions from the aqueous solutions.