Study on the formation of Fe-C-N sites during exogenous nitrogen-enhanced in-situ reconstruction of coal gasification fine slag and corresponding catalytic performance.

The full-component decomposition and reorganization of inert coal gasification fine slag (CGFS) could be achieved through exogenous enhancement, and this approach was also an inevitable choice for enterprises to realize clean production. In this work, a strategy for activating the CGFS structure via non-metallic heteroatomic nitrogen doping was proposed. CGFS was subjected to mechanical ball milling to obtain ball-milled CGFS (MCGFS), and the carbon-ash synergistic catalyst N d -MCGFS was further synthesized through dicyandiamide doping and hydrothermal treatment. The flotation-derived residual carbon (RC) and ball-milled inorganic minerals (MIM) were also prepared the composites N d -RC and N d -MIM under the same conditions. Under suitable conditions, the N d -MCGFS/PMS system achieved a BPA removal rate of 97.00 % within 60 min. The prepared N d -MCGFS had a nitrogen content of 0.73 %, an Fe N structure proportion of 18.80 %, and a specific surface area of 132.07 m 2 /g, while catalysts using RC or MIM alone as substrates showed inferior performance The mineral-based N d -MIM only achieved 45.81 %, while the residual carbon-based N d -RC mainly relied on adsorption. The residual carbon pores and mineral metal sites could promote carbon-ash synergy and enhance catalytic performance. In the N d -MCGFS/PMS system, PMS was activated by C O bonds and nitrogen species to generate reactive oxygen species (ROS). BPA degradation was realized through the cycle of high-valent iron‑oxygen species and electron transfer. The Fe leaching amount was approximately 43 times lower than that of the CGFS. This provides a new approach for the high-value utilization of CGFS.