College of Architecture and Environment, Sichuan University, Chengdu 610000, China.
Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Water Res. 2024 Apr 1;253:121353. doi: 10.1016/j.watres.2024.121353. Epub 2024 Feb 21.
Ozonation of wastewater containing bromide (Br) forms highly toxic organic bromine. The effectiveness of ozonation in mitigating wastewater toxicity is minimal. Simultaneous application of ozone (O) (5 mg/L) and ferrate(VI) (Fe(VI)) (10 mg-Fe/L) reduced cytotoxicity and genotoxicity towards mammalian cells by 39.8% and 71.1% (pH 7.0), respectively, when the wastewater has low levels of Br. This enhanced reduction in toxicity can be attributed to increased production of reactive iron species Fe(IV)/Fe(V) and reactive oxygen species (•OH) that possess higher oxidizing ability. When wastewater contains 2 mg/L Br, ozonation increased cytotoxicity and genotoxicity by 168%-180% and 150%-155%, respectively, primarily due to the formation of organic bromine. However, O/Fe(VI) significantly (p < 0.05) suppressed both total organic bromine (TOBr), BrO, as well as their associated toxicity. Electron donating capacity (EDC) measurement and precursor inference using Orbitrap ultra-high resolution mass spectrometry found that Fe(IV)/Fe(V) and OH enhanced EDC removal from precursors present in wastewater, inhibiting electrophilic substitution and electrophilic addition reactions that lead to organic bromine formation. Additionally, HOBr quenched by self-decomposition-produced HO from Fe(VI) also inhibits TOBr formation along with its associated toxicity. The adsorption of Fe(III) flocs resulting from Fe(VI) decomposition contributes only minimally to reducing toxicity. Compared to ozonation alone, integration of Fe(VI) with O offers improved safety for treating wastewater with varying concentrations of Br.
废水含溴（Br）经臭氧化会形成高毒性的有机溴。臭氧化对减轻废水毒性的效果甚微。当废水中 Br 浓度较低时，同时施加臭氧（O）（5mg/L）和高铁酸盐（VI）（Fe（VI））（10mg-Fe/L），可分别使哺乳动物细胞的细胞毒性和遗传毒性降低 39.8%和 71.1%（pH7.0）。这种毒性降低的增强可归因于具有更高氧化能力的反应性铁物种 Fe（IV）/Fe（V）和反应性氧物种（•OH）的产量增加。当废水中含有 2mg/L 的 Br 时，臭氧化会使细胞毒性和遗传毒性分别增加 168%-180%和 150%-155%，主要是由于有机溴的形成。然而，O/Fe（VI）显著（p<0.05）抑制了总有机溴（TOBr）、BrO 及其相关毒性。使用轨道阱超高分辨率质谱仪的电子供体能力（EDC）测量和前体推断发现，Fe（IV）/Fe（V）和 OH 增强了废水中前体的 EDC 去除，抑制了导致有机溴形成的亲电取代和亲电加成反应。此外，由 Fe（VI）自分解产生的 HOBr 也抑制了 TOBr 的形成及其相关毒性。由于 Fe（VI）分解而产生的 Fe（III）絮体的吸附对降低毒性的贡献很小。与单独臭氧化相比，Fe（VI）与 O 的整合为处理不同 Br 浓度的废水提供了更高的安全性。
