Carbon dioxide capture on nitrogen-doped carbon nanoparticle derived from aromatic compounds via solution plasma and nitridation

Abstract

The carbon dioxide (CO2) adsorption on nanocarbon (C), oxygen-doped nanocarbon synthesized from benzene and a mixture of benzene and metal working fluid (MWF), respectively, via solution plasma process (SPP) have been revealed in this study. Firstly, they showed low CO2 adsorption capacity at 25 °C. However, their capacities were enhanced by nitridation under ammonia atmosphere at high temperature. The maximum CO2 adsorption capacity of 1.63 mmol g-1 was achieved on nitrogen-oxygen-codoped nanocarbon obtained from SPP discharging a mixture containing 15 vol% MWF nitrided at 800 °C (noC15(800)). The characterizations revealed that the micropososity and nitrogen functionality on the adsorbent are crucial parameters affecting the CO2 capacity. From thermodynamics insights, the adsorption on noC15(800) was physisorption, exothermic, spontaneous and with better selectivity of CO2/N2 compared to unmodified. noC15(800) also showed good stability over multi-cycle of use. The adsorption isotherm on noC15(800) over the whole pressure range at all temperatures was best fitted to the Toth isotherm referring monolayer adsorption on heterogenous surface. From the statistical analysis, micropore and nitrogen content had positive synergistic effect on adsorption capacity.