Reutilization of pyrite tailings in peracetic acid-based advanced oxidation process for water purification

Abstract

Iron-based heterogeneous catalysts in peracetic acid (PAA)-based advanced oxidation technologies are currently a considerable interest, yet the sluggish reduction from Fe(III) to Fe(II) impedes the efficiency of PAA activation. Pyrite tailings (PRT) still contains a certain amount of FeS2 composition, and its reducing sulfur species have the ability of electron-donating for Fe(III) reduction. Therefore, from the view of resource utilization and environmental protection, we applied PRT to activate PAA for removing sulfamethoxazole (SMX) in this work. In-situ Raman spectra verified the activation of PAA by PRT, and 93.67 % of SMX (5 mg/L) can be removed after 50 min in near-neutral circumstance (pH 5.8), which could be mainly attributed to the activation of PAA through the leached Fe ions from PRT. Radical scavenging and probe tests testified that hydroxyl and acetylperoxy radicals are responsible for SMX decomposition. A series of spectroscopic characterizations and theory calculation confirmed that the ability of sulfur sites to donate electrons, thereby boosting Fe(II) regeneration on PRT. The continuous catalytic test proved the sustainable utilization capacity of PRT. This study presented PRT as an effective catalyst with potential uses for PAA-based wastewater treatment process.