Experimental and DFT Investigation of Phenol Adsorption onto Cobalt Nanoparticles-Modified Porous Carbon

Removal of phenolic compounds from the environment is an essential aspect of environmental remediation to maintain a clean environment. In this current study, groundnut shell-derived activated carbon (GN-900) was synthesized and then supported with cobalt nanoparticles via the solid-state impregnation method to obtain GN-900-Co. The Co-supported GN-900 (i.e., GN-900-Co), its precursor (GN-900) and commercial activated carbon were used separately to remove phenol from contaminated water. The characterization of GN-900 and GN-900-Co sorbents was examined employing X-ray diffraction, Raman spectroscopy, FTIR, SEM, TEM, and N₂-sorption. The adsorption capacity of phenol in 2 h is quite impressive with 126.6 mg/g, equivalent to 91% efficiency in 51.3 mg/L using 1 g/L adsorbent. The kinetic and isotherm data show that the pseudo-second-order and Langmuir models, correspondingly, described the adsorption mechanism of phenol. DFT calculation showed that modifying AC with cobalt reduced its chemical hardness, improved dipole–dipole interactions, and increased the adsorption capacity for phenol molecules removal. The remarkable removal efficiency of the GN-900-AC-Co demonstrated its enormous potential in contaminated water treatment.