Study on the adsorption of 2,4-dichlorophenoxyacetic acid on silver doped carbon nanotube using tight-binding quantum chemical method

The GFN2-xTB tight-binding quantum chemical method was utilized to investigate the adsorption ability of 2,4dichlorophenoxylacetic acid (2,4-D) on pristine single-walled carbon nanotube (CNT) and silver-doped carbon nanotube (Ag-CNT). The effects of solvents (water, methanol, and acetonitrile) on the adsorption process were evaluated via the linear Poisson -Boltzmann analysis algorithm. The analysis of ionization energy, electron affinity, and global electrophilic indexes indicates that Ag doping alters the electronic properties of CNT through the formation of Ag -C chemical bonds. While the adsorption process of 2,4-D on pristine CNT is primarily of a physical nature, the adsorption on Ag-CNT involves chemical adsorption facilitated by the formation of Ag -Cl and Ag -O bonds. Contributions from non -covalent interactions (such as n -n stacking, van der Waals interactions, etc.) were analysed and clarified through the computation of the reduced density gradient. Our findings suggest that Ag-CNT has significant potential as a material for the adsorption and remediation of 2,4-D.