In this work, the electrochemical oxidation of methyl paraben (MeP) with diamond electrodes is studied. Results point out that this preservative can be easily removed from wastewater, either in sulfate or chloride media. Pollutant removal is faster in chloride media due to the chlorination of the molecule. However, mineralization is faster in sulfate media. Current density does not have a clear influence on the efficiency, explained by a mediated oxidation control of the process. Irradiation by UV light produces a synergistic effect on the process, which is greater in sulfate than in chloride media, a behavior that could be initially understood in terms of the formation of sulfate and chloride radicals. However, chemical tests showed that persulfate is not active for the oxidation of MeP neither in dark conditions nor under UV irradiation and that hypochlorite is active in the chlorination of the MeP molecule but not in the mineralization. Consequently, these results can be better explained considering the oxidizing effect of ozone and hydrogen peroxide, which are produced during the electrolysis on the surface of diamond, and that within the reaction conditions undertaken, are unstable and decompose to hydroxyl radicals. Regarding electrolysis in chloride media, although chlorates or perchlorates are produced, UV light significantly delays the appearance of both species.

在这项工作中，研究了金刚石电极对羟基苯甲酸甲酯（MeP）的电化学氧化。结果指出，在硫酸盐或氯化物介质中，可以很容易地从废水中去除这种防腐剂。由于分子的氯化作用，在氯化物介质中污染物的去除速度更快。但是，在硫酸盐介质中矿化速度更快。电流密度对效率没有明显的影响，可以通过介导的过程氧化控制来解释。紫外线照射对该过程产生协同作用，硫酸盐中的协同作用大于氯化物介质中的协同作用，这种行为最初可以通过形成硫酸盐和氯化物自由基来理解。然而，化学测试表明，过硫酸盐在黑暗条件下和紫外线照射下均不具有MeP的氧化活性，次氯酸盐在MeP分子的氯化中具有活性，而在矿化中则不具有活性。因此，考虑到在钻石表面电解过程中产生的臭氧和过氧化氢的氧化作用，并且在进行的反应条件下不稳定并分解为羟基自由基，可以更好地解释这些结果。关于在氯化物介质中的电解，尽管会生成氯酸盐或高氯酸盐，但紫外线会大大延迟这两种物质的出现。考虑到在钻石表面电解过程中产生的臭氧和过氧化氢的氧化作用，并且在进行的反应条件下不稳定并分解为羟基自由基，可以更好地解释这些结果。关于在氯化物介质中的电解，尽管会生成氯酸盐或高氯酸盐，但紫外线会大大延迟这两种物质的出现。考虑到在钻石表面电解过程中产生的臭氧和过氧化氢的氧化作用，并且在进行的反应条件下不稳定并分解为羟基自由基，可以更好地解释这些结果。关于在氯化物介质中的电解，尽管会生成氯酸盐或高氯酸盐，但紫外线会大大延迟这两种物质的出现。