Simple Catalytic Approach for Removal of Analytical Interferences Caused by Hydrogen Peroxide in a Standard Chemical Oxygen Demand Test.

To enable the evaluation of water treatment efficiency of electrochemical advanced oxidation processes (EAOPs), an approach to remove H2O2 as a catalytic pretreatment was investigated to avoid interference in chemical oxygen demand (COD) measurements. Four wastewater types with COD and H2O2 concentrations up to 1,300 mg/L and 90 mmol/L , respectively, were investigated with a novel method. The method requires the addition of sodium bicarbonate (NaHCO3), which decomposes H2O2 at ambient temperature within 24 h without changing COD. For synthetic wastewater (SWW), this time is reduced to 1 h by heating at 70°C. A side-by-side comparison of NaHCO3 and Na2CO3 experiments confirmed H2O2 removal without changes in COD via NaHCO3 , whereas a ∼20% decrease in original COD was observed using Na2CO3. The change in COD during catalytical H2O2 decomposition in Na2CO3 solution was highly correlated with the high pH value. [ABSTRACT FROM AUTHOR]