Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210018, China.
Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
Chemosphere. 2022 Aug;301:134728. doi: 10.1016/j.chemosphere.2022.134728. Epub 2022 Apr 26.
A hierarchically ordered macroporous RuO electrode (HOM-RuO) was fabricated to enhance in situ active chlorine production in an electrochemical system intended for treatment of pharmaceutical active compounds (PhACs). The unique structure of HOM-RuO resulted in a decrease of the chlorine evolution potential, a large electro-active area available for in situ conversion of Cl to active chlorine, and hence improved the active chlorine production by 40%. 5-Fluorouracil (5-FU) was used as a target pollutant to explore the performance of the HOM-RuO for PhACs degradation based on the in situ generated active chlorine. The results showed that the reaction rate of active-chlorine-mediated oxidation of 5-FU produced using the HOM-RuO was 18.4 times higher than that in the case of hydroxyl radicals (OH)-initiated oxidation using a PbO electrode at 30 mA cm. The effects of current density and initial solution pH on the 5-FU removal were investigated. The mechanism of 5-FU degradation was proposed taking into accounts both active chlorine production, and change of the speciation of 5-FU caused by pH variations. The dominant degradation products observed for the degradation of 5-FU using the HOM-RuO were lactic acid, propanol, acetic acid, urea and other small molecules, but no chlorinated products were detected. These study demonstrates the promise of the HOM-RuO-based electrochemical systems for the active-chlorine-mediated treatment of recalcitrant pharmaceuticals found in wastewater.
一种分级有序的大孔 RuO 电极（HOM-RuO）被制备出来，以增强电化学系统中原位活性氯的产生，该系统旨在处理药物活性化合物（PhACs）。HOM-RuO 的独特结构导致氯析出电位降低，用于原位将 Cl 转化为活性氯的有效电活性面积增大，从而使活性氯的产生提高了 40%。5-氟尿嘧啶（5-FU）被用作目标污染物，以探索 HOM-RuO 基于原位生成的活性氯对 PhACs 降解的性能。结果表明，使用 HOM-RuO 产生的活性氯介导的 5-FU 氧化反应速率比使用 PbO 电极在 30 mA cm 时由 OH 引发的氧化反应速率高 18.4 倍。研究了电流密度和初始溶液 pH 值对 5-FU 去除的影响。考虑到活性氯的产生以及 pH 值变化引起的 5-FU 形态变化，提出了 5-FU 降解的机理。使用 HOM-RuO 降解 5-FU 时观察到的主要降解产物是乳酸、丙醇、乙酸、尿素和其他小分子，但未检测到氯化产物。这些研究表明，基于 HOM-RuO 的电化学系统有望用于处理废水中存在的难处理药物的活性氯介导处理。
