The photooxidative degradation of poorly soluble organic compounds in water (oleic acid, β-naphthol); toluene and asphaltene/toluene solubilized, oleic acid emulsified in sodium dodecylsulphate at various compositions and selfemulsifiable crude oil in water were investigated in TiO2 aqueous (0.1 m/v%) suspension in photoreactor (γ = 240-375 nm). The concentration of various organic compounds chosen as model pollutants (oleic acid, β-naphthol) decreased linearly as a function the irradiation time, the reaction seemed to be zero order. During one hour irradiation the degraded TOC values (5 and 6 ppm) were measured, both these molecules had been oxidized to CO2 at the same rate. The concentration of sodium dodecylsulphate (SDS) readily soluble in water also decreased linearly and the efficiency during 10 hours of irradiation is higher (ΔTOC = 68 ppm) than in the cases of poorly soluble organic materials (ΔTOC = 25 ppm) due to higher solubility. The effect of oxidizing agent H2O2 on efficiency for degradation of SDS has been studied. Increasing the concentration of the oxidizing agent had an effect on the efficiency of the mineralization as hydroxyl radicals were produced, which reacted with the organic material over different radical processes. It was found that the efficiency was increasing up to 0.2-0.3 m/v% of titania in aqueous suspension, while the photooxidative process was prevented between 0.3 and 0.4 m/v%. According to mineralized TOC specified (ΔTOC/g titania) the highest efficiency was shown in the case of 0.1 % of TiO2. Organic substances poorly soluble in water (toluene, asphaltene soluble in toluene) were solubilized in the micelles of sodiumdodecylsulphate at 1 CM and 2 CM in water and the solubilized pollutant material was mineralized together with the micelles, with parallel monitoring of TOC values using H2O2 oxidant. The concentration was not decreased linearly during the irradiation because of addition of oxidant. Higher efficiency was shown in the case of crude oil selfemulsifiable in water despite the fact that the organic material had not been stabilized by surfactant. Without H2O2 during 10 hours the extent of degradation was twenty per cent, while using H2O2 (1M) fifty per cent.
|Translated title of the contribution||Photooxidative degradation of organic molecules solubilized and emulsified in aqueous medium containing TiO2|
|Number of pages||11|
|Journal||Magyar Kemiai Folyoirat, Kemiai Kozlemenyek|
|Publication status||Published - May 1 2002|
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