Laboratory of Leather and Environmental Studies (LACOURO), Chemical Engineering Department, Federal University of Rio Grande do Sul (UFRGS), Av. Luiz Englert s/n°, 90040- 040, Porto Alegre, Brazil.
Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, n° 9500, 91501-970, Porto Alegre, Brazil.
Bull Environ Contam Toxicol. 2020 Sep;105(3):433-439. doi: 10.1007/s00128-020-02954-2. Epub 2020 Aug 1.
Direct photolysis of the emerging contaminant 2-(thiocyanomethylthio) benzothiazole (TMCTB) was performed in aqueous solution at different concentrations with high-pressure mercury lamp (5.0, 8.0, 13.0, 16.0, 20.0, 23.0, 27.0, 35.0, 40.0, 45.0, and 50.0 mg L) and with natural sunlight radiation (6.0, 30.0, and 60.0 mg L). TCMTB underwent rapid degradation by direct photolysis with a high-pressure mercury lamp in aqueous solutions, with 99% removal after 30 min at all concentrations studied. For sunlight photolysis, TCMTB degradation was observed with 96%, 81%, and 64% removal for initial concentrations of 6.0, 30.0, and 60.0 mg L, respectively, after 7 h of exposure to sunlight. The degradation of TCMTB in lab-scale wastewater had kinetic constant and t in the same order when compared to the photodegradation of TCMTB in aqueous solutions. In addition, the results showed that photolysis with a high-pressure mercury lamp and sunlight were governed by the same kinetic order, however the kinetic parameters showed that degradation with sunlight was 40 times slower than photolysis with the mercury lamp. Twelve transformation products (TP) were identified, and eight of the TP have not been described in the literature. Furthermore, prediction of toxicity with ECOSAR software was carried out for fish, daphnids, and green algae species. It showed that photolytic treatment is efficient for reducing the toxicity of the compound, since the degradation formed compounds with lower toxicity than the primary compound. In conclusion, this study suggests that photolysis is an efficient way to remove the studied contaminant, and it highlights the potential of this technique for the degradation of emerging contaminants in industrial wastewater treatment plants.
在不同浓度下（5.0、8.0、13.0、16.0、20.0、23.0、27.0、35.0、40.0、45.0 和 50.0mg/L），采用高压汞灯和自然光辐射（6.0、30.0 和 60.0mg/L）对新兴污染物 2-（硫氰基甲基硫代）苯并噻唑（TMCTB）在水溶液中进行直接光解。在所有研究浓度下，TMCTB 在高压汞灯下的水溶液中通过直接光解迅速降解，30min 后去除率达到 99%。对于太阳光光解，在初始浓度分别为 6.0、30.0 和 60.0mg/L 时，暴露在阳光下 7h 后，TMCTB 的降解率分别为 96%、81%和 64%。实验室规模废水的降解动力学常数和半衰期与 TMCTB 在水溶液中的光降解相同。此外，结果表明，高压汞灯和太阳光的光解遵循相同的动力学顺序，然而动力学参数表明，太阳光降解比汞灯光解慢 40 倍。共鉴定出 12 种转化产物（TP），其中 8 种 TP 在文献中未被描述。此外，还使用 ECOSAR 软件对鱼类、水蚤和绿藻物种进行了毒性预测。结果表明，光解处理可有效降低化合物的毒性，因为降解形成的化合物毒性比原化合物低。总之，本研究表明光解是去除研究污染物的有效方法，并强调了该技术在工业废水处理厂中降解新兴污染物的潜力。
