Van Cong Tran, Hung Nguyen Duc, Tran Thi Ngoc Dung, Van Hoang Nguyen, Vattikuti Surya Veerendra Prabhakar, Dang Nam Nguyen
Institute of New Technology, 17 Hoang Sam Street, Cau Giay District, Hanoi 100000, Vietnam.
Institute of Environmental Technology, VAST, 18 Hoang Quoc Viet Street, Cau Giay District, Hanoi 100000, Vietnam.
ACS Omega. 2021 Sep 29;6(40):26329-26337. doi: 10.1021/acsomega.1c03487. eCollection 2021 Oct 12.
Herbicide compounds containing aromatic rings and chlorine atoms, such as 2,4,5-trichlorophenoxyacetic (2,4,5-T), cause serious environmental pollution. Furthermore, these compounds are very difficult to decompose by chemical, physical, and biological techniques. Fortunately, the high-voltage direct current electrochemical technique can be controlled to form a plasma on metallic electrodes. It creates active species, such as H, O, and HO, and free radicals, such as H, O, and OH. Free radicals that have a high oxidation potential (e.g., OH) are highly effective in oxidizing benzene-oring compounds. Iron electrodes are used in the study to combine the dissolving process of the iron anode electrode to create Fe ions and the electrochemical Fenton reaction. In addition, the flocculation process by Fe(OH) also occurs and the plasma appears with a voltage of 5 kV on the iron electrode in a solution of 30 mg L of 2,4,5-T. After a period of time of the reaction, the aromatic-oring compounds containing chlorine were effectively treated, and the electric conductivity of the solution increased due to the amount of Cl ions released in the solution and the decrease in the pH value. The degradable products of 2,4,5-T were qualitatively characterized by gas chromatography-mass spectrometry (GC-MS), and it was determined that straight-chain carboxylic acids are formed in the solution. These compounds are easy to oxidize thoroughly under appropriate conditions in a solution via OH free radicals. Moreover, 2,4,5-T was also quantitatively analyzed using a calibration curve from GC-MS and high-performance liquid chromatography (HPLC). Furthermore, this work also suggests that the performance of the treatment process can be optimized by controlling the technological factors, such as the input voltage, the distance between anodic and cathodic electrodes, the initial concentration of 2,4,5-T, and flowing air through the solution that represents an approximately 99.83% degradable efficiency. Finally, the work demonstrates a potential technology for treating the 2,4,5-T compound, particularly for environmental pollution treatments.
含有芳香环和氯原子的除草剂化合物，如2,4,5-三氯苯氧乙酸（2,4,5-T），会造成严重的环境污染。此外，这些化合物很难通过化学、物理和生物技术进行分解。幸运的是，可以控制高压直流电化学技术在金属电极上形成等离子体。它会产生诸如H、O和HO等活性物种以及诸如H、O和OH等自由基。具有高氧化电位的自由基（如OH）在氧化含苯环化合物方面非常有效。本研究中使用铁电极，将铁阳极电极的溶解过程与电化学芬顿反应相结合，生成Fe离子。此外，还会发生Fe(OH)的絮凝过程，在30 mg/L的2,4,5-T溶液中，铁电极上施加5 kV电压时会出现等离子体。经过一段时间的反应，含氯的芳香环化合物得到有效处理，溶液的电导率因溶液中释放的Cl离子量增加以及pH值降低而升高。通过气相色谱-质谱联用仪（GC-MS）对2,4,5-T的降解产物进行了定性表征，确定溶液中形成了直链羧酸。这些化合物在溶液中适当条件下很容易通过OH自由基被彻底氧化。此外，还使用GC-MS的校准曲线和高效液相色谱（HPLC）对2,4,5-T进行了定量分析。此外，这项工作还表明，通过控制诸如输入电压、阳极和阴极电极之间的距离、2,4,5-T的初始浓度以及使空气流过溶液等工艺因素，可以优化处理过程的性能，降解效率约为99.83%。最后，这项工作展示了一种处理2,4,5-T化合物的潜在技术，特别是用于环境污染治理。
