Polychoro-1,3-butadienes (CBDs) were widely found in aqueous environment and resistant to conventional water treatment. In this study, the abatement of CBDs during UV/chlorine treatment was investigated. In comparison to UV irradiation alone, free chlorine addition brought benefits for the reduction of tetra-CBDs (TCBDs), but to lesser extent for penta-CBDs (PCBDs), and virtually no benefit for hexa-CBD (HCBD). At a UV dose of 128 mJ cm⁻² and a chlorine dose of 10 mg L⁻¹, about 71.7–97.8% CBDs were degraded by UV/chlorine treatment within 10 min. UV irradiation contributed 32.8%–97.6%, HO^• contributed 2.6%–14.4%, and reactive chlorine species (RCS) contributed less than 0.5%–42.3% to CBDs degradation. The percentages of RCS contribution generally followed the order of TCBDs (except (Z,Z)-1,2,3,4-TCBD) > PCBDs > HCBD. The chlorine oxide radical (ClO^•) was the dominant RCS contributing to the degradation of CBDs. The second-order reaction rate constants of ClO^• with CBDs (${\text{k}}_{{\text{ClO}}^{•}\text{,CBDs}}$) were at ∼ 10⁷ M⁻¹s⁻¹ except (Z,Z)-1,2,3,4-TCBD and HCBD (˂ 10⁶ M⁻¹s⁻¹). ${\text{k}}_{{\text{ClO}}^{•}\text{,CBDs}}$ generally decreased with increasing numbers of chlorine atoms and was also affected by the positions of chlorine atoms in CBDs. A distinct reaction pathway of ClO^•, with (Z)-1,1,2,3,4-PCBD as a representative CBD, was proposed. Photoisomers of CBDs from Z or E configuration were observed at lower concentrations in UV/chlorine treatment than under UV irradiation alone due to the radical-involved oxidation, but more organic acids including oxalic acid were observed. In a natural water sample, UV/chlorine treatment also exhibited a good performance in abatement of TCBDs and PCBDs, but not in abatement of HCBD.

在水性环境中广泛发现多氯-1,3-丁二烯（CBD），并且耐常规水处理。在这项研究中，研究了紫外线/氯气处理过程中CBD的减少。与单独的紫外线照射相比，添加游离氯为减少四-CBD（TCBD）带来了好处，但对五-CBD（PCBD）的影响却较小，而对六-CBD（HCBD）几乎没有好处。在UV剂量为128 mJ cm ^-2和氯剂量为10 mg L ^{-1的情况下}，在10分钟内通过UV /氯处理降解了约71.7–97.8％的CBD。紫外线照射占32.8％–97.6％，HO ^•贡献了2.6％–14.4％，而活性氯物种（RCS）对CBD的降解贡献不到0.5％–42.3％。RCS贡献的百分比通常遵循TCBD的顺序（（Z，Z）-1,2,3,4-TCBD除外）> PCBD> HCBD。氧化氯自由基（ClO ^•）是导致CBD降解的主要RCS。ClO ^•与CBDs的二阶反应速率常数（${\text{ķ}}_{{\text{氯}}^{•}\text{中央商务区}}$）为〜10 ⁷  M ^-1 s ^-1，（Z，Z）-1、2、3、4-TCBD和HCBD为（10 ⁶  M ^-1 s ^-1）。${\text{ķ}}_{{\text{氯}}^{•}\text{中央商务区}}$通常随着氯原子数量的增加而减少，并且还受CBD中氯原子位置的影响。提出了以（Z）-1,1,2,3,4-PCBD为代表的CBD的ClO ^•的独特反应途径。由于自由基参与的氧化作用，在Z / E构型的CBD的光异构体在UV /氯处理中的浓度低于单独在UV照射下的浓度，但观察到更多的有机酸，包括草酸。在天然水样品中，UV /氯处理在减少TCBD和PCBD方面也表现出良好的性能，但在减少HCBD方面却没有。