This research investigated chlorinated byproduct formation at Ti₄O₇ anodes. Resorcinol was used as a model organic compound representative of reactive phenolic groups in natural organic matter and industrial phenolic contaminants and was oxidized in the presence of NaCl (0—5 mM). Resorcinol mineralization was >68% in the presence and absence of NaCl at 3.1 V/SHE (residence time = 13 s). Results indicated that ∼4.3% of the initial chloride was converted to inorganic byproducts (free Cl₂, ClO₂^–, ClO₃^–) in the absence of resorcinol, and this value decreased to <0.8% in the presence of resorcinol. Perchlorate formation rates from chlorate oxidation were 115—371 mol m^–2 h^–1, approximately two orders of magnitude lower than reported values for boron-doped diamond anodes. Liquid chromatography–mass spectroscopy detected two chlorinated organic products. Multichlorinated alcohol compounds (C₃H₂Cl₄O and C₃H₄Cl₄O) at 2.5 V/SHE and a monochlorinated phenolic compound (C₈H₇O₄Cl) at 3.1 V/SHE were proposed as possible structures. Density functional theory calculations estimated that the proposed alcohol products were resistant to direct oxidation at 2.5 V/SHE, and the C₈H₇O₄Cl compound was likely a transient intermediate. Chlorinated byproducts should be carefully monitored during electrochemical advanced oxidation processes, and multibarrier treatment approaches are likely necessary to prevent halogenated byproducts in the treated water.

中文翻译：

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Magnéli相Ti4O7电极在电化学高级氧化过程中形成氯化副产物。

这项研究调查了在Ti ₄ O ₇阳极上氯化副产物的形成。间苯二酚被用作​​模型有机化合物，代表天然有机物和工业酚类污染物中的反应性酚基，并在NaCl（0-5 mM）存在下被氧化。在3.1 V / SHE的NaCl存在和不存在下，间苯二酚的矿化度> 68％（停留时间= 13 s）。结果表明，初始氯化~4.3％转化为无机副产物（游离氯₂，CLO ₂ ^-，CLO ₃ ^- ）在没有间苯二酚，并且该值在间苯二酚的存在减少到<0.8％。氯酸盐氧化产生的高氯酸盐形成速率为115-371 mol m ^–2h ^–1，比硼掺杂金刚石阳极的报告值低大约两个数量级。液相色谱-质谱法检测到两种氯化有机产物。提出了在2.5 V / SHE下的多氯醇化合物（C ₃ H ₂ Cl ₄ O和C ₃ H ₄ Cl ₄ O）和在3.1 V / SHE下的单氯酚化合物（C ₈ H ₇ O ₄ Cl）作为可能的结构。密度泛函理论计算估计，所提出的醇产品在2.5 V / SHE和C ₈ H ₇ O _4下具有抗直接氧化的能力Cl化合物可能是瞬时中间体。在电化学高级氧化过程中，应仔细监测氯化副产物，并且可能需要采用多壁垒处理方法来防止处理后水中的卤化副产物。