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）工艺去除水中TMP及其植物毒性，并与单独氯化法和单独紫外辐照法进行对比。本研究通过合成水样与实际出水水样，考察了包括氯投加量、溶液pH值及TMP初始浓度在内的多种处理工况。相较于单独氯化与单独紫外辐照，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的去除效果最佳，氯化法次之，而单独紫外辐照对TMP的去除仅存在微弱影响（去除率不足5%）。紫外/氯工艺在接触反应15分钟时即可完全去除TMP，而氯化法需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（如Cl•、OCl•），羟基自由基（HO•）是影响TMP去除与降解速率的核心氧化剂。TMP暴露会降低莴苣（Lactuca sativa）与绿豆（Vigna radiata）种子的发芽率，从而增强其植物毒性。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等同于甚至低于不含TMP的原出水。脱毒效率与TMP去除率呈正相关，其数值约为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应用潜力。