Precision Pore Structure Optimization of Asphalt-Derived Porous Carbon for Effective Adsorption of Dichloromethane: Molecular Simulation and Experimental Study

The pore size distribution of porous carbon is crucial for efficient dichloromethane (DCM) adsorption. This study employed Grand Canonical Monte Carlo simulations to identify an optimal pore size range of 0.4–1.0 nm for DCM adsorption. Experimentally, microporous carbons were synthesized from asphalt using K₂CO₃ as an activator, with pore structures tailored by varying activation conditions. The optimized sample achieved a maximum adsorption capacity of 210 mg/g (C₀ = 400 ppm, T = 25 °C), demonstrating a strong correlation (R² = 0.997) between pore volume (<1.0 nm) and adsorption capacity, consistent with simulation predictions. Isotherm and thermodynamic analyses indicated that the adsorption process adhered to the Langmuir and Dubinin–Radushkevich models (R² > 0.99) and was spontaneous and exothermic. Reusability tests showed 91% of the adsorption capacity retention after five cycles, highlighting the material’s practical potential. These findings provide insights into DCM adsorption mechanisms and guidelines for designing efficient porous carbons.