College of Environmental Science and Engineering, Tongji University

重金属-有机络合物废水因其难以被生物降解,是工业废水治理的重要难题之一。首次提出采用还原和络合能力更强的多羟基结构态亚铁(FHC)还原破络Cu(Ⅱ)-EDTA以去除铜。利用原位生成的CuFe2O4、Cu2O等活性金属催化臭氧(O3)生成·OH,促进有机配体的完全矿化,最终实现重金属和有机配体的同步去除。在优化条件下,当FHC的[Fe2+]∶[OH−]配比为1∶3,投加量为2mmol/L,O3剂量为10mg/min时,可在60min内将0.2mmol/LCu(Ⅱ)-EDTA中的铜和有机配体完全去除,且无残留铁存在。当[FHC(1∶3)]∶[Cu(Ⅱ)-EDTA]高于5∶1时,可确保铜被完全破络去除,并且通过提高FHC中[OH−]的比例,而非增加FHC投加量,可以提高Cu(Ⅱ)-EDTA破络去除的经济性。研究表明,该工艺不受、、等常见阴离子的影响,具备良好的抗环境干扰能力。破络后原位生成的CuFe2O4、Cu2O以及臭氧催化氧化后形成的Fe3O4均具有磁性,具备磁力分离的潜力。电子自旋共振(EPR)结果证实了原位生成产物可催化O3产生·OH、和。淬灭实验结果显示,加入叔丁醇(TBA)后EDTA的去除率从100.0%降至57.7%,间接证明·OH参与了EDTA的降解。基于LC-MS的分析结果证明,FHC还原破络Cu(Ⅱ)-EDTA形成乙二胺四乙酸铁(Fe-EDTA),通入O3后,Fe-EDTA中的N—C键被·OH和O3破坏,连续脱羧形成三乙酸乙二胺铁(Fe-ED3A)、二乙酸乙二胺铁(Fe-ED2A)、甘氨酸、次氮基三乙酸铁(Fe-NTA)和次氮基三乙酸(NTA)等中间产物,或进一步通过乙酸基团取代形成亚胺二乙酸铁(Fe-IMDA)和亚胺二乙酸(IMDA),并最终矿化为CO2和H2O。该技术对于重金属-有机络合物废水治理具有借鉴参考意义。

Heavy metal-organic complexes in industrial wastewater pose significant challenges due totheir resistance to biological treatment. This study proposes the use of ferrous hydroxyl complex (FHC)Energy Environmental Protectionto break down copper ethylenediaminetetraacetate (Cu(Ⅱ)-EDTA) and remove copper, leveraging itsstrong reduction and complexation capabilities. The process involves in situ generation of CuFeO andCuO from the reduction of Cu(Ⅱ)-EDTA by FHC. These active metal species catalyze the productionof hydroxyl radicals (·OH) from ozone (O), promoting the further mineralization of organic ligands andachieving synchronous removal of heavy metals and organic ligands. Under optimized conditions, the[Fe]∶[OH] ratio of FHC is 1∶3, with a dosage of 2 mmol/L for FHC and 10 mg/min for O. Thisallows the complete removal of 0.2 mmol/L Cu(Ⅱ)-EDTA within 60 minutes, with no residualdissolved iron. A ratio of [FHC (1∶3)]∶[Cu(Ⅱ)-EDTA] exceeding 5∶1 ensures completedecomplexation and removal of copper. The economic efficiency of Cu(Ⅱ)-EDTA decomplexation andremoval can be enhanced by increasing the proportion of [OH] in FHC rather than increasing thedosage of FHC. The process exhibits strong resistance to common anions such as chloride (Cl), nitrate(), and sulfate (), indicating its practical applicability in diverse wastewater. The in situgenerated CuFeO, CuO, and FeO after ozonation are magnetic, offering potential for magneticseparation and further enhancing cost-effectiveness. To validate the mechanism, electron paramagneticresonance (EPR) analysis was conducted. The results confirmed that the in situ generated products caneffectively catalyze the production of hydroxyl radicals (·OH), singlet oxygen (O), and superoxideradicals () from O. Quenching experiments were performed to investigate the role of reactiveoxidative species (ROS) in the degradation of EDTA. The results showed that the removal rate ofEDTA decreased from 100.0% to 57.7% upon the addition of tert-butanol (TBA), indirectly proving theinvolvement of ·OH in the degradation of EDTA. Liquid chromatography-mass spectrometry (LC-MS)analysis provided insights into the reaction pathways. The decomplexation of Cu(Ⅱ)-EDTA by FHCforms iron ethylenediaminetetraacetate (Fe-EDTA), and subsequent ozonation leads to the disruption ofthe N—C bonds in Fe-EDTA by ·OH and O, generating intermediate products such as ironethylenediaminetriacetate (Fe-ED3A), iron ethylenediaminediacetate (Fe-ED2A), glycine, Fe-nitrilotriacetate (Fe-NTA), and nitrilotriacetic acid (NTA). Further reactions may involve thesubstitution of acetyl groups to form Fe-iminodiacetate (Fe-IMDA) and iminodiacetic acid (IMDA),ultimately mineralizing to CO and HO. In conclusion, this innovative technique provides a promisingprospect for the treatment of heavy metal-organic complex wastewater, crucial for environmentalprotection and industrial sustainability.

国家自然科学基金资助项目(52170091,42377390)

邰伟,叶国杰,何群彪,等.多羟基亚铁耦合臭氧同步去除重金属和有机物——以Cu(Ⅱ)-EDTA去除为例[J].能源环境保护,2025,39(1):113−126.

TAI Wei, YE Guojie, HE Qunbiao, et al. Simultaneous Removal of Heavy Metals and Organic Matter byFerrous Hydroxyl Complex Coupled with Ozone: A Case Study of Cu(Ⅱ)-EDTA Removal[J]. EnergyEnvironmental Protection, 2025, 39(1): 113−126.