Coal gasification wastewater (CGW) contains a large amount of toxic pollutants, which seriously affects the subsequent biochemical treatment. In order to investigate the efficiency of electrocatalytic oxidation on pretreatment of CGW, lead dioxide electrodes doped with PEG and Bi were successfully prepared. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were comprehensively used to characterize the lead dioxide electrode and the electrochemical performance was also tested by linear sweep voltammetry curve, cyclic voltammetry curve and AC impedance. Biodegradability and toxicity of CGW were evaluated by dehydrogenase activity and acute toxicity, respectively. Results showed that the doping of PEG and Bi significantly improved the electrochemical performance and catalytic oxidation performance of lead dioxide electrodes. The degradation rate of phenol by Sn-Sb/PbO2 (PEG + Bi) electrode were 1.57 times of that by pure lead dioxide electrode. The removal of TOC and total phenols were 53.2% and 82.7%, respectively at 120 min under 40 mA cm-2 by Sn-Sb/PbO2 (PEG + Bi) electrode. The changes of biodegradability, biological toxicity and by-products were analyzed. Furthermore, 3,5-dimethylphenol was used as characteristic pollutant to study the degradation mechanism of phenolic pollutants in electrocatalytic system. According to the intermediate products detected by GC-MS, possible degradation pathways in electrocatalytic system were proposed.

中文翻译：

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双掺杂PbO2电极对煤气化废水的电化学预处理：阳极的制备，效率和机理。

煤气化废水（CGW）含有大量有毒污染物，严重影响后续的生化处理。为了研究电催化氧化对CGW预处理的效率，成功制备了掺有PEG和Bi的二氧化铅电极。广泛使用扫描电子显微镜，能量色散谱和X射线衍射来表征二氧化铅电极，并通过线性扫描伏安曲线，循环伏安曲线和交流阻抗测试了电化学性能。通过脱氢酶活性和急性毒性分别评估了CGW的生物降解性和毒性。结果表明，PEG和Bi的掺杂显着提高了二氧化铅电极的电化学性能和催化氧化性能。Sn-Sb / PbO2（PEG + Bi）电极对苯酚的降解速率是纯二氧化铅电极的1.57倍。Sn-Sb / PbO2（PEG + Bi）电极在40 mA cm-2下于120分钟时的TOC和总酚去除率分别为53.2％和82.7％。分析了生物降解性，生物毒性和副产物的变化。此外，以3,5-二甲基苯酚为特征污染物，研究了酚类污染物在电催化体系中的降解机理。根据GC-MS检测到的中间产物，提出了电催化体系中可能的降解途径。Sn-Sb / PbO2（PEG + Bi）电极对苯酚的降解速率是纯二氧化铅电极的1.57倍。Sn-Sb / PbO2（PEG + Bi）电极在40 mA cm-2下于120分钟时的TOC和总酚去除率分别为53.2％和82.7％。分析了生物降解性，生物毒性和副产物的变化。此外，以3,5-二甲基苯酚为特征污染物，研究了酚类污染物在电催化体系中的降解机理。根据GC-MS检测到的中间产物，提出了电催化体系中可能的降解途径。Sn-Sb / PbO2（PEG + Bi）电极对苯酚的降解速率是纯二氧化铅电极的1.57倍。Sn-Sb / PbO2（PEG + Bi）电极在40 mA cm-2下于120分钟时的TOC和总酚去除率分别为53.2％和82.7％。分析了生物降解性，生物毒性和副产物的变化。此外，以3,5-二甲基苯酚为特征污染物，研究了酚类污染物在电催化体系中的降解机理。根据GC-MS检测到的中间产物，提出了电催化体系中可能的降解途径。分析了生物毒性和副产物。此外，以3,5-二甲基苯酚为特征污染物，研究了酚类污染物在电催化体系中的降解机理。根据GC-MS检测到的中间产物，提出了电催化体系中可能的降解途径。分析了生物毒性和副产物。此外，以3,5-二甲基苯酚为特征污染物，研究了酚类污染物在电催化体系中的降解机理。根据GC-MS检测到的中间产物，提出了电催化体系中可能的降解途径。