Grupo de Investigación en Remediación Ambiental y Biocatálisis (GIRAB), Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
Grupo de Investigación en Remediación Ambiental y Biocatálisis (GIRAB), Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia; Unidad Profesional Interdisciplinaria en Ingeniería y Tecnologías Avanzadas-Instituto Politécnico Nacional, Av. IPN No. 2580, Gustavo A. Madero, C.P. 07340 Ciudad de México, Mexico.
Sci Total Environ. 2019 Jan 15;648:377-387. doi: 10.1016/j.scitotenv.2018.08.148. Epub 2018 Aug 11.
The elimination of cephalexin (CPX) using electro-generated Cl-active on Ti/RuO-IrO anode was assessed in different effluents: deionized water (DW), municipal wastewater (MWW) and urine. Single Ti/RuO and Ti/IrO catalysts were prepared to compare their morphologies and electrochemical behavior against the binary DSA. XRD and profile refinement suggest that Ti/RuO-IrO forms a solid solution, where RuO and IrO growths are oriented by the TiO substrate through substitution of Ir by Ru atoms within its rutile-type structure. SEM reveals mud-cracked structures with flat areas for all catalysts, while EDS analysis indicates atomic ratios in the range of the oxide stoichiometries in the nominal concentrations used during synthesis. A considerably higher CPX degradation is achieved in the presence of NaCl than in NaSO or NaPO media due to the active chlorine generation. A faster CPX degradation is reached when the current density is increased or the pH value is lowered. This last behavior may be ascribed to an acid-catalyzed reaction between HClO and CPX. Degradation rates of 22.5, 3.96, and 0.576 μmol L min were observed for DW, MWW and urine, respectively. The lower efficiency measured in these last two effluents was related to the presence of organic matter and urea in the matrix. A degradation pathway is proposed based on HPLC-DAD and HPLC-MS analysis, indicating the fast formation (5 min) of CPX-(S)-sulfoxide and CPX-(R)-sulfoxide, generated due the Cl-active attack at the CPX thioether. Furthermore, antimicrobial activity elimination of the treated solution is reached once CPX, and the initial by-products are considerably eliminated. Finally, even if only 16% of initial TOC is removed, BOD tests prove the ability of electro-generated Cl-active to transform the antibiotic into biodegradable compounds. A similar strategy can be used for the abatement of other recalcitrant compounds contained in real water matrices such as urine and municipal wastewaters.
采用 Ti/RuO-IrO 阳极电生成的 Cl 活性物质去除头孢氨苄（CPX），在不同的废水中进行了评估：去离子水（DW）、城市废水（MWW）和尿液。制备了单 Ti/RuO 和 Ti/IrO 催化剂，以比较它们的形态和电化学行为与二元 DSA 的对比。XRD 和轮廓细化表明，Ti/RuO-IrO 形成固溶体，其中 RuO 和 IrO 的生长通过 TiO 衬底的取代作用，由 Ru 原子在其金红石型结构中取代 Ir 原子来定向。SEM 显示所有催化剂均为泥裂结构，具有平坦区域，而 EDS 分析表明原子比在合成过程中使用的标称浓度的氧化物化学计量范围内。由于活性氯的产生，在有 NaCl 的情况下，CPX 的降解率明显高于有 NaSO 或 NaPO 的情况下。当电流密度增加或 pH 值降低时，CPX 的降解速度更快。这种最后一种行为可能归因于 HClO 和 CPX 之间的酸催化反应。在 DW、MWW 和尿液中分别观察到 22.5、3.96 和 0.576 μmol L min 的 CPX 降解速率。在最后两种废水中测量的效率较低与基质中存在有机物和尿素有关。根据 HPLC-DAD 和 HPLC-MS 分析，提出了一种降解途径，表明 CPX-(S)-亚砜和 CPX-(R)-亚砜的快速形成（5 分钟），这是由于 CPX 硫醚的 Cl 活性攻击所致。此外，一旦 CPX 及其初始副产物被大量消除，处理后的溶液的抗菌活性就会被消除。最后，即使仅去除初始 TOC 的 16%，BOD 测试也证明了电生成的 Cl 活性将抗生素转化为可生物降解化合物的能力。类似的策略可用于去除尿液和城市废水中等实际水基质中含有的其他难处理化合物。
