Adsorption of chlorobenzene onto (5,5) armchair single-walled carbon nanotube and graphene sheet: toxicity versus adsorption strength

Abstract

Adsorption of the homologues series of chlorobenzenes (CBs) onto the surface of the (5,5) armchair single-walled carbon nanotube (SWCNT) and graphene (Graph) sheet has been investigated using density functional theory-based calculations, and the concomitant interaction between the CBs and SWCNT/Graph has also been characterized with the help of the Bader’s theory of atoms in molecules. Results reveal that interaction of CBs with the SWCNT and Graph enhances with the increase in the chlorine content. The adsorption of CBs on Graph is more favorable when compared with SWCNT. Evidence shows that the planar surface of the graphene facilitates the direct through-space interaction of the chlorine atoms of CBs with the aromatic surface. The π character of CBs governs the interaction process in the case of SWCNT. Findings from this study clearly demonstrate the importance of geometry (curved or planar) of the nanomaterial in the adsorption of aromatic pollutants. In addition, the inter-relationship between the electrophilicity index (a powerful conceptual DFT descriptor of toxicity of CBs) and the interaction energy (adsorption capacity) has also been derived.