Numerical simulations on the adsorption characteristics of aromatics on activated carbon by the GCMC method

Aromatics cause environmental pollution and seriously threaten human health. Currently, adsorption is regarded as an economical and practical method for aromatics removal. This work aims to explore the adsorption characteristics of benzene, toluene, p-xylene on activated carbon (AC) by the Grand Canonical Monte Carlo method (GCMC). The influence of functional groups (-H and -OH), the density, mesopore size of AC, and classes of aromatics on the adsorption characteristics was analyzed. It was found that -H and -OH functional groups could increase the isosteric heat of aromatics on AC and increase the adsorption capacity in low pressure. As the density of AC increases, the free volume inside AC decreases, and isosteric heat of adsorption increases obviously, resulting in a decrease in saturated adsorption capacity and the saturated adsorption pressure, respectively. The aromatics molecular diameter and mesopore size have a noticeable effect on the adsorption behavior. As the molecular diameter increases, the saturated adsorption pressure decreases. When the pressure is high enough, the mesopores could enhance the adsorption capacity of AC dramatically.