Mechanism of Advanced Oxidation Technique with Iron to Remove COD

Abstract

The research on the two advanced oxidation techniques of Fenton reagent and potassium ferrate is long-standing, and the basic principle of its reaction is also gradually clear. However, the mechanism of removal of COD by these two methods is not perfect. The mainstream view is that COD removal is mainly based on the complete oxidation of organics, followed by the flocculation of iron. It is believed that most of the organics are oxidized, and only a small part is precipitated with iron ions to achieve COD removal, but during the actual experiment founded it's not like that. In this paper, the Fenton reagent oxidized glucose experimental analysis found that the simple reduction of COD by oxidation was very limited, but in the initial condition PH = 6, COD = 428mg/L, with addition 1.67ml H2O2 (30%)/L, 1.36gFeSO4•7H2O/L. After 40min, the iron ions were difficult to flocculate and the effluent COD was 335mg/L. If a certain amount of Ca(OH)2 were added, the iron ions are precipitated and the water COD was measured as 70 mg/L, if the resulting precipitate regulated the acidity and the precipitate dissolved, the solution's COD rose again to 312 mg/L. This shows that the latter has a much higher effect on reducing COD than the former thought little research has been done in this phenomenon.