Studies in mineralization of aqueous aniline using Fenton and wet oxidation (FENTWO) as a hybrid process

A hybrid process for mineralization of aqueous aniline using Fenton and wet oxidation (FENTWO) is studied. It is important to have maximum conversion of ‘N’ atoms from the waste to N2. The conversion of input ‘N’ atoms in aniline to N2 was 15% during wet oxidation without the Fenton process and was improved to 50% with the Fenton process. Therefore, a hybrid process of Fenton followed by wet oxidation was studied for mineralization of the aqueous aniline stream. The parameters for the Fenton process were optimized (pH, catalyst, H2O2 to catalyst (FeSO4) ratio, quantity of H2O2). The waste obtained after the Fenton process was then treated by wet oxidation for mineralization by having homogeneous CuSO4 as the catalyst by keeping FeSO4 therein. This combined catalyst was found to be more effective for the degradation of the intermediates formed in the Fenton process. Wet oxidation (WO) was studied in the temperature range 473–513 K and the oxygen partial pressure range 0.345–1.38 MPa at pH 6.5. The kinetic data was modeled using a power law rate expression in terms of chemical oxygen demand (COD). The optimum temperature for formation of more N2 gas was found to be 493 K. The treated waste stream was found to contain oxalic acid using HPLC, and NH4+, NO3− and NO2− ions using ion chromatography analysis. Copyright © 2007 Society of Chemical Industry