Abstract

Nosrat Madadi Mahani, Asghar Amiri and Nagmeh Noroozmahani

DOI : http://dx.doi.org/10.13005/ojc/330309

Benzoic acid (BA) is the typical aromatic monocarboxylic acid often found in domestic and industrial wastewaters. Single-walled carbon nanotubes (SWCNTs), due to their large adsorption capacity, can be used as a new type of adsorbent for the removal of various pollutants from wastewater, such as BA. The (6, 6) and (5, 5) SWCNTs, as adsorbent of the BA compound, have been investigated by theoretical calculations in this study. All calculations have been performed using the DMol3 code, which is based on density functional theory (DFT). The density functional theory was considered within the generalized gradient approximation (GGA) and local density approximation (LAD). The HOMO, the LUMO, energy gap, and electrophilic and nucleophilic attack areas of the reactivity of BA were calculated. The Fukui analysis of descriptor functions shows that the atoms of oxygen are suitable sites for a nucleophilic attack. A molecular dynamics simulation was employed to determine the adsorption behaviour of the BA compound on SWCNTs. The rigid adsorption energy, deformation energy, and adsorption energy were released when the BA was adsorbed on the SWCNTs. The adsorption energy (E_ads) values revealed high energy in the BA molecule towards the SWCNT surface. The values of E_ads with the two methods were negative, which indicates that the adsorption could occur spontaneously  on the surface. The value of E_ads was negative, which indicates that the adsorption could occur spontaneously.

Benzoic acid (BA); Adsorption energy; Single Walled Carbon Nanotube; Interaction; Density Functional Theory (DFT)

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