Carboxymethylcellulose and cellulose xanthate matrices as potential adsorbent material for potentially toxic Cr3+, Cu2+ and Cd2+metal ions: a theoretical study

Abstract

Cellulose derivatives have been synthesized and used in various applications with emphasis on possible application in environmental remediation. In this context, the present work theoretically studied the adsorption of Cr3+, Cu2+ and Cd2+ metal ions in the carboxymethylcellulose (CMC) and cellulose xanthate (CX) matrices, both derived from cellulose. From the calculations, it was possible to obtain map of electrostatic potential, frontier molecular orbitals, reactivity indices, and with these, analyses infer that the cations would interact with the CMC and CX oxygen and also with the CX sulfo group. After complexation, the results showed that the CX and CMC matrices studied have potential to be used to remove toxic metals and presented chemical adsorption and the processes occur spontaneously (ΔG < 0). The topological analysis of quantum theory of atoms in molecules allowed to characterize the nature of the interaction, in which the interactions in position “b” of CMC–Cu2+, CMC–Cd2+ and position “a” of CMC–Cd2+ and “a” in the complexes XC–Cu2+, XC–Cd2+ and “b” in the XC–Cr3+ site (1) presented electrostatic characteristics, and the other interactions were partially covalent. The results found when compared to the study of cellulose and cellulose acetate adsorption with the same metal ions showed that the theoretical data provide insights for a possible experimental approach and use of this matrices.