Preparation of hierarchically porous carbon ash composite material from fine slag of coal gasification and ash slag of biomass combustion for CO2 capture

Abstract

With the spread and development of industrialization, CO2 emissions are increasing dramatically, posing a serious threat to the global ecosystem. Based on coal gasification fine slag (CGFS) pore structure characteristics, CGFS was used to prepare carbon-ash composite hierarchically porous material by chemical activation and hydrothermal methods for CO2 capture. It would achieve comprehensive and high value utilization of CGFS. In addition, the biomass combustion ash slag (BCA) is rich in alkali and metal elements, there are extremely important influence on CGFS pore formation. Therefore, the alkali and potassium sources were extracted in leaching experiments for CGFS-based porous materials preparation. It was found that the prepared porous material had a large specific surface area (1270 m2/g), a graded porous structure and excellent CO2 adsorption capacity (4.06 mol/kg at 0 °C), while the pores of the BCA-impregnated porous material were further developed with a larger specific surface area (1406 m2/g) and more functional groups on porous material surface. All these results indicate the relevance between using BCA impregnates and material performance enhancement. Furthermore, the CGFS-based graded porous composite porous materials have great potential for repurposing in practical and industrial CO2 adsorption applications.