A Density Functional Theory Study on the Interaction of Cellulose Biopolymer and Atomic Arsenic

Abstract

Here, we provide a description of arsenic (As) adsorption on the cellulose biopolymer using first-principles density functional theory. In all studied configurations, the process of As adsorption on the cellulose is an exothermic process indicated by the negative binding energy. The cellulose's hydroxyl and hydroxymethyl groups significantly interact with As atom, characterized by the binding energy. In all optimized configurations, the interactions are mainly described as chemical bonding. This claim is supported by the overlap of the electron localization function (ELF) in the interface of As and cellulose in all studied adsorption sites. The adsorption of As on the cellulose introduces new states in the vicinity of the Fermi energy, leading to the lower bandgap of the cellulose-As systems. Overall, these results imply that the As atom can be trapped and detected using cellulose-based material. These findings offer an explanation of earlier research works on cellulose-As systems. This work will also serve as a reference for fabricating cellulose-based material for sensing and removing As.