A grand canonical Monte Carlo study of SO2 capture using functionalized bilayer graphene nanoribbons.

Grand canonical Monte Carlo (GCMC) simulation is used to study the adsorption of pure SO2 using a functionalized bilayer graphene nanoribbon (GNR) at 303 K. The functional groups considered in this work are OH, COOH, NH2, NO2, and CH3. The mole percent of functionalization considered in this work is in the range of 3.125%-6.25%. GCMC simulation is further used to study the selective adsorption of SO2 from binary and ternary mixtures of SO2, CO2, and N2, of variable composition using the functionalized bilayer graphene nanoribbon at 303 K. This study shows that the adsorption and selectivity of SO2 increase after the functionalization of the nanoribbon compared to the hydrogen terminated nanoribbon. The order of adsorption capacity and selectivity of the functionalized nanoribbon is found to follow the order COOH > NO2 > NH2 > CH3 > OH > H. The selectivity of SO2 is found to be maximum at a pressure less than 0.2 bar. Furthermore, SO2 selectivity and adsorption capacity decrease with increase in the molar ratio of SO2/N2 mixture from 1:1 to 1:9. In the case of ternary mixture of SO2, CO2, N2, having compositions of 0.05, 0.15, 0.8, the selectivity of SO2 over N2 is higher than that of CO2 over N2. The maximum selectivity of SO2 over CO2 is observed for the COOH functionalized GNR followed by NO2 and other functionalized GNRs.