Fe(Ⅵ)-CaSO3体系对磺胺甲嘧啶的去除效能与机制OA

Sulfamerazine(SMZ)is a widely used sulfonamide antibiotic that can be detected in surface water at concentrations up to the µg·L−1 level.Conventional water treatment processes struggle to effectively remove it,posing serious risks to both the ecological environment and human health.Ferrate(Fe(Ⅵ))is an environmentally friendly multifunctional agent,but its oxidation capacity still requires enhancement through activation.Calcium sulfite(CaSO3)serves as an effective slow-release activator for Fe(Ⅵ).However,the removal efficiency and mechanism of Fe(VI)-CaSO3 system for SMZ removal need further investigation.Results indicate that with an Fe(Ⅵ)dosage of 30 μmol·L−1 and a molar ratio of[Fe(Ⅵ)]:[CaSO3]=1:3,the Fe(Ⅵ)-CaSO3 system achieved an SMZ removal rate of 81.10%within 10 min.This system is primarily governed by high-valent iron species(Fe(Ⅴ)/Fe(Ⅳ)),with the participation of·OH and SO4·−,forming a multi-reactive oxidation system.The main degradation pathways of SMZ in the Fe(Ⅵ)-CaSO3 system involve the cleavage of N–C and S–C bonds.Moreover,the oxidative degradation of SMZ is accompanied by an overall reduction in toxicity.In terms of water matrix effects,Cl−,SO42−,and NO3− had negligible impacts on the degradation efficiency.High concentrations of Ca2+and Mg2+slightly promoted oxidative degradation,whereas HCO3− and humic acid showed significant inhibitory effects.Furthermore,the Fe(Ⅵ)-CaSO3 oxidation system achieved a minimum SMZ removal rate of 67.20%across four different real water samples,demonstrating its ability to adapt to complex real water environments and exhibiting strong universality.