Adsorptive Removal of Organochlorine from Oils by Modified Activated Carbon: Effect of Surface Groups and Kinetic and Thermodynamic Studies

Activated carbon (AC) treated with nitric acid (HNO3) and hydrogen peroxide (H2O2) was prepared for the study of the effect of oxygen-containing functional groups on the adsorptive removal of organochlorines from oil. The adsorption performance and physicochemical properties of the adsorbents were tested and analyzed. The results show that the HNO3–H2O2 comodified AC (NPAC) presented the best adsorptive efficiency, especially for the removal of aromatic chlorides. It has been found that the surface chemical groups and the physical texture of AC play major roles in the adsorption performance of organic chlorides. The potential of activated carbon (NPAC) treated with nitric acid and hydrogen peroxide in removing organic chlorine from oil was comprehensively evaluated through experimental data combined with mathematical models of kinetics and equilibrium. The adsorption process conforms to the Freundlich isotherm equation, which proves that there is multilayer adsorption in the adsorption process, and 1,2-dichlorobenzene (DCB) is more easily adsorbed by modified AC. The kinetic results indicate that there is chemical adsorption during the adsorption process, and the diffusion process of organic chlorides in AC is influenced by several factors.