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 N 2 . The conversion of input ‘N’ atoms in aniline to N 2 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, H 2 O 2 to catalyst (FeSO 4 ) ratio, quantity of H 2 O 2 ). The waste obtained after the Fenton process was then treated by wet oxidation for mineralization by having homogeneous CuSO 4 as the catalyst by keeping FeSO 4 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 N 2 gas was found to be 493 K. The treated waste stream was found to contain oxalic acid using HPLC, and NH 4 + , NO 3 − and NO 2 − ions using ion chromatography analysis. Copyright © 2007 Society of Chemical Industry