Through naphthalene-adsorption experiments, we were able to draw some valuable conclusions about adsorption capacity, the adsorption isotherm, adsorption kinetics, and adsorption thermodynamics, although the experiments could not directly reveal the exact location and state of adsorption on the surface of ordered mesoporous carbons (OMCs). In fact, due to the restrictions of characterization technology, human factors, and experimental conditions, we still do not understand the microscopic structure of OMCs very well. However, molecular simulation technology could compensate for these disadvantages. In this study, the Grand Canonical Monte Carlo method has been used to simulate the naphthalene adsorption behavior in the OMC-structure model for the first time. The atomic structure model of OMCs was built firstly by using molecular modeling techniques and was characterized by calculating the accessible solvent surface area, total pore volume, and small-angle X-ray diffraction patterns. The calculated results showed that the structural model of OMCs was reasonable and that the structural characteristics were in agreement with experimental data. The adsorption isotherm curve is of the type Langmuir IV, which is a typical characteristic of ordered mesoporous materials. Also, the adsorption isotherm curve revealed that the adsorption capacity of naphthalene on OMCs gradually increased to a balance, with the maximum capacity reaching 105.4 mg g–1. Additionally, as the number of naphthalene molecules increased, the adsorption state was observed progressing from a monolayer to a multilayer state in the mesopores.
This work deepened the understanding of the adsorption state of naphthalene for OMCs on the mesoscopic level. It also demonstrated that the GCMC method is effective for studying the adsorption process and gives useful guidance on research of the structure-activity relationship and performance prediction of carbon material.