二氧化铅粉末多孔电极处理氨氮废水的研究

采用高压塑片法制备纯PbO₂电极及掺杂石墨+活性炭混合粉体的PbO₂粉末多孔电极，通过扫描电镜、循环伏安手段对电极性能进行了表征，并以氨氮模拟废水为处理对象进一步考察电极的电催化性能。结果表明，PbO₂粉末多孔电极具有较高的导电性及电催化活性，最佳掺杂量为15%~20%。氨氮的去除率随电流密度和氯离子浓度的增大而增加。初始pH为3.0~10.0时，氨氮的去除率随初始pH的升高而降低；初始pH为11.0~12.0时，氨氮的去除率随初始pH的升高而升高。氨氮降解的主要机理是阳极产生的强氧化物（·OH、HClO和ClO^-）的间接氧化，其产物是以N₂为主的含氮气体及少量的硝酸盐氮。

Research on the Treatment of Ammonia-nitrogen Wastewater by Lead Dioxide Power Porous Electrode

Pure PbO2 electrode and PbO2 powder porous electrode which was modified by adding graphite and activated carbon powder, were prepared by high pressure molding. The electrode properties were evaluated by means of SEM and cyclic voltammetry. Furthermore, the electrocatalytic property was further examined through the treatment of ammonia-nitrogen wastewater. It was showed that PbO2 powder porous electrode was better in view of electrical conductivity and electrocatalytic activity and the optimum mass percentage of graphite and activated carbon powder was 15% to 20%. Removal efficiency of ammonia nitrogen was improved continuously with increasing current density and increasing concentration of chloride ion added. Besides, ammonia-nitrogen removal efficiency reduced continuously with increasing pH when the initial pH was between 3.0-10.0, but increased when that was between 11.0-12.0. The treatment of ammonia-nitrogen wastewater by PbO2 powder porous electrode was due to strong oxidizing substances, such as ·OH, HClO and ClO-, which were produced by the electrocatalytic activity of anode, and the ammonia-nitrogen was finally oxidized into NOx gas mainly with N2 and with small amount of nitrate nitrogen.