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.