Comparison of the PAHs degradation effectiveness using CaO2 or H2O2 under the photo-Fenton reaction

In this paper, the results of comparison of the polycyclic aromatic hydrocarbons (PAHs) degradation efficiency with using H2O2 or CaO2 under the conditions of the photo-Fenton reaction have been presented. The research was conducted using the coke wastewater, pretreated in a biological, factory wastewater treatment plant. Despite of purification in biological treatment plant, coke wastewater should be subjected to an additional purification process. Purification was carried out with the use of advanced photochemical oxidation. Various doses of calcium peroxide or hydrogen peroxide and a constant dose of iron sulfate FeSO4 center dot 7H(2)O were added to the samples of wastewater. Next, the samples were exposed to UVC radiation, with a wavelength lambda = 264 nm for 480s. The effectiveness of the oxidants was evaluated based on changes in the chemical oxygen demand and total organic carbon index values and changes in the concentrations of selected PAHs. The extraction of PAHs from the samples was carried out in a liquid-liquid system using a mixture of cyclohexane and dichloromethane. A qualitative and quantitative analysis of PAHs was carried out using a gas chromatograph with a mass spectrometer. After the chemical photooxidation process, the concentrations of total PAHs in coke wastewater decreased. While maintaining the same process conditions, the PAHs degradation efficiency using CaO2 and FeSO4 7H(2)O was 43%-97%, and with using H2O2 and FeSO4 7H(2)O was 54%-96%. The removal efficiency of individual hydrocarbons was in the range of 0%-99.9%.