Abstract The environmental effects of characteristic pollutants arsenite (AsO2-) and ammonium (NH4+) produced in the process of tungsten smelting cannot be ignored. Through the ozonation experiment of AsO2- and NH4+, it is confirmed that AsO2- with lower redox potential (-0.560 V) is more readily oxidized than NH4+ (-0.283 V), leading to the coexistent AsO2- inhibiting the ozonation of NH4+. In order to improve the oxidation efficiency of NH4+, prepared CeO2-MnO2 composite metal oxide catalysts before and after reaction were characterized by SEM, EDS, FT-IR technics, and investigated for the catalytic ozonation of wastewater containing AsO2- and NH4+. When the initial AsO2- concentration is maintained at 2 mg/L and the NH4+ concentration increases from 25 to 150 mg/L, the conversion of AsO2- to AsO43- remains above 97%, while the NH4+ removal rate decreases from 94.38% to 47.01%, in which confirms the competitive effect of AsO2- oxidation prior to NH4+. Moreover, the test of catalyst dosage reconfirms the result of AsO2- oxidation superior to NH4+, and the optimum catalyst dosage is 1.5 g/L. After the test of tert-butyl alcohol (TBA), the possible oxidation mechanism is proposed that AsO2- is oxidized primarily by O3, whereas the oxidation of NH4+ is mainly ascribed to the hydroxyl radical (·OH) obtained from catalytic decomposition of O3 by CeO2-MnO2 composite metal oxide catalysts.

中文翻译：

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氧化系统中AsO2-和NH4+的竞争效应

摘要 钨冶炼过程中产生的特征污染物亚砷酸盐(AsO2-)和铵(NH4+)对环境的影响不容忽视。通过 AsO2- 和 NH4+ 的臭氧化实验，证实具有较低氧化还原电位 (-0.560 V) 的 AsO2- 比 NH4+ (-0.283 V) 更容易被氧化，导致共存的 AsO2- 抑制了 NH4+ 的臭氧化。为提高NH4+的氧化效率，对反应前后制备的CeO2-MnO2复合金属氧化物催化剂进行SEM、EDS、FT-IR等技术表征，并研究其对含AsO2-和NH4+废水的催化臭氧化作用。当初始 AsO2- 浓度维持在 2 mg/L 且 NH4+ 浓度从 25 增加到 150 mg/L 时，AsO2- 向 AsO43- 的转化率保持在 97% 以上，而 NH4+ 去除率从 94.38% 下降到 47.01%，这证实了 AsO2- 在 NH4+ 之前氧化的竞争效应。此外，催化剂用量的测试再次证实了AsO2-氧化优于NH4+的结果，最佳催化剂用量为1.5 g/L。经过对叔丁醇（TBA）的测试，提出可能的氧化机理是 AsO2- 主要被 O3 氧化，而 NH4+ 的氧化主要归因于 O3 催化分解得到的羟基自由基（·OH） CeO2-MnO2复合金属氧化物催化剂。