García-Espinoza Josué D, Robles Irma, Gil Víctor, Becerril-Bravo Elías, Barrios Jose A, Godínez Luis A
Centro de Investigación y Desarrollo Tecnológico en Electroquímica S.C., Parque Tecnológico Qro. Sanfandila, 76703, Pedro Escobedo, QRO, Mexico.
Instituto de Ingeniería, Universidad Nacional Autónoma de México, 04510, CDMX, Mexico.
J Environ Chem Eng. 2019 Aug;7(4):103228. doi: 10.1016/j.jece.2019.103228.
The electro-Fenton degradation of Triclosan in aqueous solution was studied using a cylindrical reactor in which polarized carbon cloth electrodes and a cation exchange resin were employed. Using a factorial design of experiments approach, the effect of four variables (considering two levels for each one), was measured on four response parameters that reflect the electrooxidation efficiency of the electrochemical reactor. The results revealed that in all cases triclosan degradation was very efficient (above 95%) and that while there is a reasonable effect of all variables and their interactions, the one with the strongest influence on the process is the nature and magnitude of the ionic strength of the electrolytic solution. In this way, while the presence of a buffer species in this solution can keep the pH in a value that affects the generation of OH radicals from the Fenton mixture, a high ionic strength solution can promote the elimination of Fe ionic species from the reactor by decreasing resin Fe retention due to competition effects of other ions for the binding sites of the substrate. HPLC experiments of the effluent solutions, also revealed that the degradation by-products of triclosan were dependent on the nature and ionic strength of the electrolytic solution in the electro-Fenton process under study. Finally, comparison of the different operation modes, also suggested that electro-adsorption of Fe cationic species in the negatively polarized cathode surface, is the main factor that controls Fe ion retention within the reactor.
采用圆柱形反应器研究了水溶液中三氯生的电芬顿降解过程，该反应器中使用了极化碳布电极和阳离子交换树脂。采用析因实验设计方法，测量了四个变量（每个变量考虑两个水平）对反映电化学反应器电氧化效率的四个响应参数的影响。结果表明，在所有情况下，三氯生的降解效率都很高（超过95%），虽然所有变量及其相互作用都有一定影响，但对该过程影响最大的是电解液离子强度的性质和大小。这样，虽然溶液中缓冲物质的存在可以使pH值保持在影响芬顿混合物中羟基自由基生成的值，但高离子强度溶液可以通过降低其他离子对底物结合位点的竞争效应导致的树脂铁保留，促进铁离子从反应器中去除。流出液的高效液相色谱实验还表明，在所研究的电芬顿过程中，三氯生的降解副产物取决于电解液的性质和离子强度。最后，不同操作模式的比较也表明，负极极化阴极表面铁阳离子物种的电吸附是控制反应器内铁离子保留的主要因素。
