Exploring the Functionality of Cellulose Biopolymer as Carbon Nanotube Composite and Heavy Metals Adsorbent Material: Insights from First-Principles Calculations

Abstract

Herein, using first-principles density functional theory, we explored the applicability of cellulose as a functional material of carbon nanotubes and as an adsorbent material for heavy metals (As, Hg, and Pb). The calculations revealed that cellulose is suitable for the non-covalent functionalization of SWCNT. The interaction of SWCNT with cellulose is mainly classified as physical interaction. This claim is supported by the results of binding energy, equilibrium distances, and charge transfer analysis of the SWCNT and cellulose. The electronic structure of the prototype SWCNT in the cellulose nanocomposite is well maintained, where no visible hybridization of the orbital characters is observed. The calculations explain experimental observations that cellulose is suitable for the noncovalent functionalization of SWCNT. Further calculations show that As and Pb can be trapped by cellulose biopolymer, while Hg indicates weak interaction. A significant reduction of the bandgap of cellulose is observed upon adsorption of As and Pb. These findings show cellulose can be used as an adsorbent sensing material for As and Pb. Overall, the results of this study confirm that cellulose is a promising functional material for SWCNT and a renewable adsorbent material for heavy metals.