National Engineering Research Center for Urban Pollution Control, Tongji University, Shanghai 200092, China.
Water Sci Technol. 2010;61(1):107-18. doi: 10.2166/wst.2010.808.
To be best of our knowledge, this study is one of the first investigations to be performed into the potential benefits of gas diffusion electrode (GDE) system in controlling inactivation of E. coli. This study mainly focused on the dual electrodes disinfection with gas diffusion cathode, using Escherichia coli as the indicator microorganisms. The effects of Pt load W(Pt) and the pore-forming agent content W(NH(4)HCO(3)) in GDE, operating conditions such as pH value, oxygen flow rate Q(O(2)), salt content and current density on the disinfection were investigated, respectively. The experimental results showed that the disinfection improved with increasing Pt load W(Pt), but its efficiency at Pt load of 3 per thousand was equivalent to that at Pt load of 4 per thousand. Addition of the pore-forming agent in the appropriate amount improved the disinfection while drop of pH value resulted in the rapid rise of the germicidal efficacy and the disinfection shortened with increasing oxygen flow rate Q(O(2)). The system is more suitable for highly salt water. The germicidal efficacy increased with current density. However, the accelerating rate was different: it first increased with the current density, then decreased, and reached a maximum at current density of 6.7-8.3 mA/cm(2). The germicidal efficacy in the cathode compartment was about the same as in the anode compartment indicating the contribution of direct oxidation and indirect treatment of E. coli by the hydroxyl radical was similar to the oxidative indirect effect of the generated H(2)O(2). This technology is expensive in operating cost, further research is required to advance the understanding and reduce the operating cost of this technology.
据我们所知，这项研究是首次探索气体扩散电极（GDE）系统在控制大肠杆菌失活方面的潜在益处的研究之一。本研究主要集中在使用气体扩散阴极的双电极消毒，以大肠杆菌作为指示微生物。研究了 GDE 中的 Pt 负载量 W(Pt)和造孔剂含量 W(NH4HCO3)、操作条件（如 pH 值、氧气流量 Q(O2)、盐含量和电流密度）对消毒的影响。实验结果表明，随着 Pt 负载量 W(Pt)的增加，消毒效果得到改善，但在 Pt 负载量为 3/1000 时的效率与 Pt 负载量为 4/1000 时的效率相当。适量添加造孔剂可提高消毒效果，而 pH 值下降会导致杀菌效果迅速上升，氧气流量 Q(O2)增加会缩短消毒时间。该系统更适用于高盐度水。杀菌效果随电流密度的增加而增加。然而，加速率不同：先是随电流密度增加，然后减少，在 6.7-8.3 mA/cm2的电流密度下达到最大值。阴极室的杀菌效果与阳极室基本相同，这表明直接氧化和羟基自由基间接处理大肠杆菌的贡献与生成的 H2O2的间接氧化作用相似。该技术的运行成本较高，需要进一步研究以提高对该技术的理解并降低运行成本。
