硫化纳米零价铁活化过二硫酸盐降解废水中四环素OA北大核心CSTPCD

Sulfidated zero-valent iron(S-nZVI)has been extensively utilized in wastewater treatment in recent years due to its superior electron transfer efficiency and selectivity.Integrating S-nZVI with advanced oxidation technology enhances the catalytic performance of the material,leading to efficient pollutant degradation.This study employs thiourea as the sulfur source to prepare highly active S-nZVI and constructs an S-nZVI-activated per-disulfide PDS oxidation system to achieve efficient tetracycline degradation.The composition and surface morphology of S-nZVI is characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),specific surface area(BET),and X-ray photoelec-tron spectroscopy(XPS).The effects of the molar ratio(S/Fe),vulcanization time,S-nZVI dosage,PDS concentration,initial pH of the solution,and coexisting ions on tetracycline(TC)degradation are examined.Active species quenching experiments and electron paramagnetic resonance(EPR)experiments explore TC degradation by both free radical and non-radical active species,while liquid chromatography-mass spectrometry(LC-MS)analyzes the potential pathways of tetracycline degradation.Test results indicated that vulcanization modification increases the specific surface area of nano-zero-valent iron(nZVI),and iron(Fe)and sulfur(S)are uniformly distributed on the surface of the material.The impact of S/Fe on TC degradation is minimal,and the degradation rate correlates positively with the dosage of S-nZVI and PDS concentration but shows a decreasing trend with prolonged vulcanization time.The S-nZVI/PDS system exhibits an enhanced TC degradation effect across a wide pH range(pH=5～9).The presence of different anions in the reaction solution variably inhibits the degradation rate of TC,with HCO3-having the most sig-nificant effect.At a S/Fe ratio of 0.028,a vulcanization time of 2 h,an S-nZVI dosage of 1 g/L,a PDS concentration of 2 mmol/L,and an unad-justed initial pH,the degradation rate of TC reaches 94.6％after 120 min of reaction.In addition to common free radicals(SO4·-and HO·),the active species in the S-nZVI/PDS system include the non-radical active substance Fe(Ⅳ),which has a minor effect on TC degradation.The primary pathways of TC degradation involve specific functional group cleavage and ring-opening reactions,ultimately leading to oxidative de-gradation into CO2 and H2O.