State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Water Res. 2018 Mar 15;131:208-217. doi: 10.1016/j.watres.2017.12.049. Epub 2017 Dec 23.
Bisphenol S (BPS), as a main alternative of bisphenol A for the production of industrial and consumer products, is now frequently detected in aquatic environments. In this work, it was found that free chlorine could effectively degrade BPS over a wide pH range from 5 to 10 with apparent second-order rate constants of 7.6-435.3 Ms. A total of eleven products including chlorinated BPS (i.e., mono/di/tri/tetrachloro-BPS), 4-hydroxybenzenesulfonic acid (BSA), chlorinated BSA (mono/dichloro-BSA), 4-chlorophenol (4CP), and two polymeric products were detected by high performance liquid chromatography and electrospray ionization-tandem quadrupole time-of-flight mass spectrometry. Two parallel transformation pathways were tentatively proposed: (i) BPS was attacked by stepwise chlorine electrophilic substitution with the formation of chlorinated BPS. (ii) BPS was oxidized by chlorine via electron transfer leading to the formation of BSA, 4CP and polymeric products. Humic acid (HA) significantly suppressed the degradation rates of BPS even taking chlorine consumption into account, while negligibly affected the products species. The inhibitory effect of HA was reasonably explained by a two-channel kinetic model. It was proposed that HA negligibly influenced pathway i while appreciably inhibited the degradation of BPS through pathway ii, where HA reversed BPS phenoxyl radical (formed via pathway ii) back to parent BPS.
双酚 S（BPS）作为生产工业和消费产品中双酚 A 的主要替代品，现在经常在水生环境中被检测到。在这项工作中发现，自由氯可以在 pH 值从 5 到 10 的较宽范围内有效降解 BPS，表观二级速率常数为 7.6-435.3 Ms。通过高效液相色谱和电喷雾电离串联四极杆飞行时间质谱共检测到包括氯化 BPS（即单/二/三/四氯 BPS）、4-羟基苯磺酸（BSA）、氯化 BSA（单/二氯 BSA）、4-氯苯酚（4CP）和两种聚合产物在内的 11 种产物。提出了两种平行的转化途径：（i）BPS 通过逐步氯亲电取代被攻击，形成氯化 BPS。（ii）BPS 通过电子转移被氯氧化，形成 BSA、4CP 和聚合产物。尽管考虑了氯的消耗，腐殖酸（HA）仍显著抑制了 BPS 的降解速率，而对产物种类的影响可以忽略不计。通过双渠道动力学模型合理地解释了 HA 的抑制作用。提出 HA 对途径 i 的影响可以忽略不计，而对途径 ii 中 BPS 的降解有明显的抑制作用，其中 HA 将 BPS 酚氧基自由基（通过途径 ii 形成）逆转为母体 BPS。
