Development of chitosan hydrogels containing modified cellulose nanostructures for metal removal and recovery from contaminated water

Abstract

The presence of metallic ions in contaminated water, coming from industrial processes and that have toxic potential, has led to great concern regarding their effects on human health. Conventional treatment processes are not adequate for their removal, so new technologies need to be investigated. The use of three-dimensional porous systems such as hydrogels is a material with the potential to remove these contaminants. Furthermore, the presence of modified nanostructures to induce a chelating effect on metallic contaminants can improve their removal. This project proposes the development of chitosan hydrogels and the use of modified cellulose nanostructures (NCs) to remove metal ions (chromium, cadmium, nickel and arsenic) that are difficult to remove and have high toxic potential. The NCs will be obtained by mechanical grinding and modified by 3 different routes: esterification with succinic anhydride, carboxymethylation, and complexation of the NCs with ethylenediaminetetraacetic acid. The hydrogels without and with the NCs (with and without modification) will be produced through the crosslinking of the chitosan structure using glutaraldehyde. The NCs and hydrogel systems will be evaluated for chemical composition, mechanical properties and adsorption and desorption capacity of metallic contaminants. It is intended to carry out a study related to the kinetics and conditions that modulate the adsorption process of metallic ions, aiming to optimize the properties of these materials and enable their use in larger scales for the removal of metallic contaminants. (AU)