Efficient removal of Cr(VI) from aqueous solutions using chitosan/Na‐alginate bio‐based nanocomposite hydrogel

Abstract

AbstractThis research article aimed to assist the works conducted to save water resources, which are rapidly depleted as a result of climate change by eliminating toxic chromium ions Cr(VI) from simulated solution. In this regard, chitosan/Na‐alginate/polyacrylic acid (CS/Na‐Alg/PAAc) and Ni/chitosan/Na‐alginate/polyacrylic acid (Ni@CS/Na‐Alg/PAAc) were created as eco‐friendly hydrogel composites via gamma radiation. The hydrogel matrix served as a basin for the in‐situ formation of Ni nanoparticles. The prepared composites were characterized by the FTIR and XRD analyses. The surface morphology of the nanocomposite was also verified via the SEM. It exhibited a dense packing of the Ni nanoparticles representing about 2.5% of the atomic percentage depicted by the EDX analysis. The swelling performance was investigated versus different pH values and the maximum swelling percent was attained as a non‐Fickian character at pH = 13 and 5 for CS/Na‐Alg/PAAc and Ni@CS/Na‐Alg/PAAc, respectively. Furthermore, the surface topographies of CS/Na‐Alg/PAAc and Ni@CS/Na‐Alg/PAAc loaded with Cr(VI) were examined by AFM at different pH values. The maximum Cr(VI) removal was top achieved at pH 8 (58.06 and 74.5 mg/g for CS/Na‐Alg/PAAc and Ni@CS/Na‐Alg/PAAc, respectively) and best fit with the Freundlich isotherm model with calculated RL values indicated a favorable adsorption.