Cu/Zn阴极对电化学消毒形成溴酸盐的抑制作用

Inhibition Effect of Cu/Zn Cathode on Bromate Formation during Electrochemical Disinfection

分别采用Cu/Zn阴极和Ti阴极与BDD阳极构建电化学体系电解模拟含溴水,对电化学过程中阴极对于消毒副产物BrO3^-生成的抑制作用进行了研究。结果表明,与Ti阴极相比,Cu/Zn阴极在电化学消毒时能有效抑制BrO3^-的形成。电流密度5mA/cm^2、初始菌落总数7kCFU/mL的条件下,取得相同灭菌率时,采用Cu/Zn阴极BrO3^-生成量仅为采用Ti阴极时的56.55%。抑制作用的主要原因是Cu/Zn阴极表面更强的电生氢质子能力,促进了电解体系内BrO3^-向Br^-转化。相比高电流密度,低电流密度条件下抑制作用更为明显;酸性条件下,较大的H+含量能够促进氢质子的形成,从而有利于Cu/Zn阴极抑制BrO3^-的形成;但在较高电流密度时,由于阴极副反应的加剧,使pH的影响明显减弱。

An electrochemical system was constructed using Cu/Zn cathode and BDD anode, the inhibition effect of Cu/Zn cathode on bromate production during electrochemical disinfection was investigated. The results showed that BrO3^- formation could be inhibited by Cu/Zn cathode during electrochemical disinfection compared to Ti cathode. On the premise of the consistent disinfection rate, the BrO3^- production using Cu/Zn cathode was just 56.55% of that using Ti cathode(current density of 5mA/cm^2, initial total bacterial count of 7 kCFU/mL). The main reason of bromate inhibition was that hydrogen proton could be more easily generated on Cu/Zn cathode surface and lead to the BrO3^- transformed to Br. The low current density was in favor of the bromate inhibition compared to high current density. The acid condition could accelerate the production of hydrogen proton with the higher H^+ content and benefit to the BrO3^- inhibition;while using high current density, the side reaction would increase in cathode which reducing the effect of pH insignificant.