BDD和PbO2电极电化学氧化苯并三氮唑的对比研究

分别构建了以掺硼金刚石膜电极(BDD)和二氧化铅电极(Pb O2)为阳极的电化学体系,对比考察了两种电极对难降解有机污染物苯并三氮唑(BTA)的降解及体系的矿化效果,并从电极产生羟基自由基(·OH)的数量与形态角度深入探讨了影响电极矿化能力大小的内在因素.结果表明:1BDD和Pb O2电极均对BTA有较好的降解效果,电解12 h后BTA去除率分别为99.48%和98.36%,但BDD电极的矿化能力明显强于Pb O2电极,电解12 h后矿化率分别为87.69%和35.96%;2BDD体系阳极·OH产生速率和阴极H2产生速率均低于Pb O2体系,即表面活性位点数量少于Pb O2电极,因此·OH数量不是决定矿化能力大小的关键;3BDD电极表面吸附氧活性更强,结合能(532.37e V)大于Pb O2(530.74e V),且表面吸附层更薄,产生的·OH形态更自由,是决定其具有更大矿化能力的关键因素.

Comparative Study of Benzotriazole Electrochemical Oxidation at Boron-doped Diamond and PbO2 Anodes

Electrochemical systems were built to investigate the degradation of benzotriazole (BTA) on boron-doped diamond (BDD) and PbO₂ anodes and give an insight into the mineralization ability of two electrodes in terms of the amount and activity of hydroxyl radicals. Results of bulk electrolysis showed that both BDD and PbO₂ displayed perfect BTA degradation performance after 12 hours' electrolysis, with the removal percentages of 99.48% and 98.36%, respectively, while the mineralization ability of BDD was much stronger than that of PbO₂, with the efficiency of 87.69% for BDD and 35.96% for PbO₂. Less hydroxyl radical and hydrogen production in BDD system suggested the less amount of active sites on BDD surface, thus further verified that the generated hydroxyl radical amount was not the primary factor determining the mineralization ability of anodes. However, BDD displayed larger binding energy of adsorbed oxygen and thinner adsorption layer than those of PbO₂, indicating that the BDD electrode surface was of greater catalytic activity, thus the generated hydroxyl radicals were more free, which was the key to its better mineralization ability.