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. ©, 2014, Institute of Chemical Materials, China Academy of Engineering Physics. All right reserved.