Study on Photocatalytic Mechanism of Fe3+ -TiO2 -Zeolite for Oilfield Wastewater Treatment

The composite photo catalyst of Fe³⁺-TiO₂-zeolite is prepared in a bench scale, which is immobilized into a zeolite matrix by means of sol-gel technique. The oilfield wastewater in Huabei oilfield was chosen as the model pollutant to evaluate photo catalytic activity under the ultraviolet light and sunlight irradiation respectively, the possible mechanism of photo catalytic oxidation was deduced. The results indicated that under conditions of the calcined temperature of 500°C, the composite photo catalyst was got by loading nano-TiO₂ of 43% and doping Fe³⁺ ions concentration of 6.04 × 10¹⁶ ions/cm³. COD concentration degraded could follow the first order kinetics and could meet the second national discharge standard of China. Meanwhile, the mechanism of doped Fe³⁺ in complex photo catalysts can capture the electrons in the conduction band, reduce the recombined rate of electrons with cavities, and improve the efficiency of light quantum.