Adsorption Property of Starch-Based Microporous Carbon Materials with High Selectivity and Uptake for C1/C2/C3 Separation

Abstract

Recovering light hydrocarbons from natural gas is of great significance in the petrochemical industry. In this work, starch-based microporous carbon materials (SMCs) were prepared using starch as a carbon source and characterized for their pore structure and surface chemistry. CH4, C2H6, and C3H8 isotherms of SMCs were determined using a volumetric method. The breakthrough experiments were carried out to evaluate the dynamic separation performance. A grand canonical Monte Carlo simulation was conducted to reveal the adsorption mechanism of these light hydrocarbons on the SMCs. Results showed that the resulting SMCs exhibited a high specific surface area of 1999 m2/g and a narrow pore size distribution within 0.5–2.0 nm. Particularly, SMCs displayed extremely high ethane and propane uptakes at 298 K and 100 kPa, reaching 5.28 mmol/g for C2H6 and 8.39 mmol/g for C3H8. Moreover, SMCs showed an ultrahigh selectivity of 27.1 for C2H6/CH4 mixtures under ambient conditions, which exceeded that of many metal–organic frameworks. Thus, SMCs have the potential for recovering light hydrocarbons from natural gas.