Background Coal gasification fly ash (CGFS) poses severe environmental threats due to its massive discharge, necessitating urgent treatment and valorization. Methods This study developed a facile chemical precipitation method to synthesize CGFS-supported iron sulfide catalyst (FeS@CGFS) for activating persulfate to treat coal chemical wastewater. Significant findings FeS@CGFS exhibited a unique coral-like structure with well-dispersed FeS nanoparticles on CGFS, effectively suppressing aggregation. The catalyst demonstrated exceptional Rhodamine B degradation activity across a broad pH range (3–9), achieving 98.64% removal of 20 mg/L RhB within 10 min under optimal conditions (pH 6, 0.060 g/L catalyst, 0.05 mM potassium persulfate). Mechanistic studies identified sulfate radicals (SO₄•⁻) and hydroxyl radicals (•OH) as primary reactive species. The coral-like structure enhanced pollutant adsorption and electron transfer, while S²⁻ facilitated Fe³⁺/Fe²⁺ cycling to sustain reactive species generation. This work provides a strategic blueprint for the high-value utilization of CGFS, and also offers a representative case for implementing the "waste-treats-waste" strategy and on-site treatment of coal chemical wastewater.
Zong et al. (Tue,) studied this question.