Engineering FeS2 nanoparticles on tubular g-C3N4 for photo-Fenton treatment of paint wastewater

An efficient photo-Fenton catalyst (FeS₂@HTCN) was designed by maximizing the synergistic effect of FeS₂ nanoparticles and hollow tubular g-C₃N₄ (HTCN). Molecule self-assembly and molten salts-assisted calcination were used to engineering the hollow structured g-C₃N₄ before anchoring FeS₂ nanoparticles on the walls of HTCN via reflux method. Compared to bulk g-C₃N₄, the unique structure of HTCN and heterojunction in the composite endowed FeS₂@HTCN with more active sites and abundant channels for electron transfer and charge separation. The enriched electrons can improve the Fe³⁺ recycling and boost Fe²⁺ catalyzed ^?OH production via H₂O₂. As-prepared photo-Fenton catalyst was successfully applied to the treatment of industrial paint wastewater. The paint wastewater with its COD as high as 8200 mg/L can be effectively degraded with 0.2 mol/L H₂O₂ in 90 min under visible light irradiation. The photo-Fenton system was further evaluated according to the process stability and economic benefit, proving that the strategy presented in this work would be applicable to the treatment of real wastewater.