A facile trace potassium assisted catalytic activation strategy regulating pore topology of activated coke for combined removal of toluene/SO2/NO

Abstract

Coal-fired organic pollutant emission is regarded as an important precursor to regional air pollution. Adsorption using activated coke has the potential to achieve the simultaneous removal of multiple gas pollutants such as SO2, NOx and the volatile organic compounds (VOCs) in organic pollutants, for which developing low-cost activated coke adsorbents with suitable pore configuration is the key. In this work, we propose a green and facile trace potassium assisted catalytic activation strategy to prepared coal-based activated cokes with simultaneously large surface areas, hierarchical pore topology and high production yield. By simply adjusting the type of potassium species and amounts added, potassium induced catalytic activities for the reaction between CO2 and coal framework can be controlled, thus yielding two types of activated cokes, namely microporous and hierarchically porous activated cokes. Evaluated as adsorbents, the optimized hierarchically porous KP_AC_2 shows outstanding toluene capacities in both single adsorption (300.3 mg·g−1) and combined adsorption (262.5 mg·g−1) cases. Moreover, KP_AC_2 also exhibits good SO2 and NO adsorption properties in combined adsorption cases due to the hierarchical storage of various adsorbates. Furthermore, the effects of H2O, O2 and temperature are investigated, providing guidelines for actual flue gas government. This work provides a green, low-cost and scalable method for preparing activated coke adsorbents used in combined adsorption of SO2, NO and VOCs, which hold potentials to replace the traditional physical or chemical activation craft and is promising in the field of coal-fired flue gas purification.