Data underlying the research of Synergistic degradation of trimethoprim and its phytotoxicity via the UV/chlorine process: Influencing factors on removal and kinetic

Occurrence of trimethoprim (TMP), recalcitrant antibiotic, and its adverse effect on ecosystem have been reported in several countries.The study aims to remove the TMP and its phytotoxicity via a UV/chlorine process, compared with chlorination and UV irradiation alone.Various treatment conditions including chlorine doses, pHs, and TMP concentrations was conducted with synthetic waters and effluent waters. The UV/chlorine process exhibited a synergistic effect on the TMP removal, compared with chlorination and UV irradiation alone. The UV/chlorine process was the most effective in removing TMP, followed by chlorination. The UV irradiation slightly affected the TMP removal (less than 5%). The UV/chlorine process completely removed TMP by 15 min contact time, while chlorination for 60 min could achieve 71% of TMP removal. The TMP removal fitted well with the pseudo first-order kinetics, and the rate constant (<em>k’</em>) increased with higher chlorine doses, lower TMP concentrations and low pH. HO• was the major oxidant affecting the TMP removal and its degradation rate, compared with other reactive chlorine species (e.g., Cl•, OCl•). The TMP exposure increased the phytotoxicity by decreasing a germination rate of <em>Lactuca sativa</em> and <em>Vigna radiata</em> seeds. The use of UV/chlorine process could effectively detoxify the TMP, resulting in the phytotoxicity level of treated waters equivalent or lower than those of TMP-free effluent water. The detoxification level depended on the TMP removal, and it was about 0.43 – 0.56 times of TMP removal. The findings indicated the potential use of UV/chlorine process in removing TMP residual and its phytotoxicity.

甲氧苄啶（trimethoprim, TMP）作为一种难降解抗生素，其在环境中的残留及其对生态系统的负面影响已在多个国家被报道。本研究旨在通过紫外/氯（UV/chlorine）工艺去除TMP并消除其植物毒性，并与单独氯化、单独紫外辐照工艺进行对比。研究以合成水样与出水水样为实验基质，考察了氯投加量、pH值及TMP初始浓度等多种工艺运行条件对处理效果的影响。相较于单独氯化与单独紫外辐照工艺，紫外/氯工艺对TMP的去除表现出协同增效作用。紫外/氯工艺对TMP的去除效果最优，氯化工艺次之；单独紫外辐照对TMP的去除效果仅微弱提升，去除率不足5%。紫外/氯工艺在反应15分钟时即可完全去除TMP，而氯化工艺需60分钟仅能实现71%的TMP去除率。TMP的去除过程符合准一级动力学（pseudo first-order kinetics）模型，其反应速率常数（k’）随氯投加量升高、TMP初始浓度降低及pH值降低而增大。相较于其他活性氯物种（reactive chlorine species，如Cl•、OCl•），羟基自由基（HO•）是影响TMP去除及降解速率的主要氧化剂。TMP暴露会降低莴苣（Lactuca sativa）与绿豆（Vigna radiata）种子的发芽率，进而增强其植物毒性。采用紫外/氯工艺可有效实现TMP的脱毒，处理后水体的植物毒性水平与不含TMP的出水相当甚至更低。脱毒效果与TMP的去除率呈正相关，其脱毒效率约为TMP去除率的0.43~0.56倍。本研究结果表明，紫外/氯工艺在去除水体中残留TMP及其植物毒性方面具有潜在应用价值。