Preparation of activated carbon adsorption materials derived from coal gasification fine slag via low-temperature air activation

Considering the considerable amount of residual carbon in coal gasification fine slag (CGFS) and the issue of lacking effective treatments, it is imperative to put forward a large-scale, green, and efficient method, achieving quantity reduction and harmless disposal. A kind of activated carbon adsorption material was prepared from CGFS with abundant carbon content (nearly 33.61 wt%) by low-temperature air activation. The CGFS-20 showed the best performance, whose specific surface area and pore volume increased by 21.5% and 7.8%, respectively. It is attributed to the slight oxidation of combustibles (main carbon) and removal of hydrocarbons blocked in pores, which can be further confirmed by FT-IR and pore analysis. In addition, the pores generated through activation are more concentrated in the 1.4–5 nm range. While the proportion of micropores, mesopores, and macropores of different activated samples did not change significantly, implying that the generation and development of pores make it realize a dynamic balance of three pore proportions. The CO2 adsorption of CGFS and CGFS-20 combined with the Langmuir model was investigated and revealed that the theoretical maximum adsorption for CO2 was 21.03 cm3/g.