高级氧化法中H_2O_2对COD的测定影响及消除

通过测定含不同H2O2浓度的纯水体系及硝基苯类化合物水样体系的废水化学需氧量(COD),分析发现硝基苯类化合物水样中H2O2对COD的测量存在正干扰,且具有很好的线性关系。在不引入新的干扰前提下,探讨了相应的H2O2消除方法。结果表明,当水样中H2O2浓度475 mg·L-1,COD值为747.6 mg·L-1时,改变水样p H值为碱性有利于H2O2的去除;添加二氧化锰催化剂虽然能在较短时间内去除H2O2,但可能引入新的干扰物;添加过氧化氢酶在不引入新的干扰情况下可快速去除H2O2。当反应时间3 min,分别调节水样p H为12、添加二氧化锰、添加过氧化氢酶,水样中H2O2去除率为1.2%、45.6%、100%。在相同酶量下处理含不同浓度H2O2的水样,H2O2均可在短时间内被除净。分析表明,添加过氧化氢酶可为快速、高效消除废水中未知浓度H2O2对CODCr测定的影响提供一条新的途径。

Interference of H2O2 on COD Test and Removal Method for Advanced Oxidation Process

The chemical oxygen demand(COD) for pure water and nitrobenzene waste water sample containing different content of H₂O₂ was measured and the linear interference of H₂O₂ concentration on COD test was studied. It shows that with increase of the H₂O₂, the COD increases. Without new interference, the ways to suppress interference of H₂O₂ on COD test were discussed including pH value, manganese dioxide catalyst, and catalase. Results show that the catalase eliminates the influence of H₂O₂ on COD determination effectively, and the alkaline environment is in favor of removing the H₂O₂ to some extent, and manganese dioxide catalyst can remove H₂O₂ in short time but it may introduce new interferences. When the reaction time is 3 min, by adjusing initial liquid pH value of 12, adding manganese dioxide catalyst and catalase, respectively, the H₂O₂ removal rate can reach 1.2%, 45.6% and 100%, indicating that catalase can conveniently remove H₂O₂ with unknown concentration, and suppress the interference of H₂O₂ on COD test.