Chitosan-based foam composites for hexavalent chromium remediation: Effect of microcellulose and crosslinking agent...

Potentially toxic metal ions, such as hexavalent chromium (Cr⁶⁺), present in water concern the population's health due to their persistence, bioaccumulation potential, and high toxicity. Highly porous materials based on polysaccharides are promising technologies for metal removal due to their high surface area, biodegradability, and low toxicity. This study evaluated the effect of concentrations of microcellulose (0.5, 1, and 1.5 %) and glutaraldehyde (1, 2, and 3 %) in the adsorption capacity and mechanical properties of chitosan foams. The developed foams exhibited a three-dimensional structure with interconnected pores. Compared to foams without microcellulose, adding 1.5 % microcellulose increased up to 180 % in maximum stress supported by the foams and up to 135 % in Young's modulus. However, Cr⁶⁺ sorption capacity decreased with increasing microcellulose and crosslinking agent content due to the occupation of amino groups. Still, the foams exhibited a highly favorable sorption behavior, and the Sips isotherm model provided the best fit to the experimental data. The maximum sorption capacity reached approximately 1.4 mmol·g^-1 at pH 4.0 and 25 °C. The foam structural integrity, enhanced mechanical properties, and efficient sorption capacity make them viable alternatives for environmentally friendly and cost-effective treatment of water contaminated with Cr⁶⁺ ions.