Study On Photocatalytic Decomposition Of Oil-polluted Water With TiO₂ Nanowires

In recent years, most oilfields in China have entered the middle and late period of development. With the oilfield produced water increasing, some oilfields have been unable to completely re-inject the oil-polluted water. Thus the standardized discharge of the oil-polluted water has become a major problem in the environmental protection of the oilfields. In addition, the composition of oily wastewater has become more and more complex. The surface water and ground water would be affected seriously if the oil-polluted water do not treated effectively, because of its characteristics, such as complex ingredient, which including conventional oil, suspended solids, acetic acid, propionic acid, cyclohexanoic acid, caprylic acid, phenolic compounds, toluene, o-xylene, m-toluene, xylene, benzene, chlorides, sulfides and other inorganics.The synthesis and assessment methods of 100g-grade titanium dioxide nanowire were established in this study.Also, a small photocatalytic degradation device and a laboratory scale continuous photocatalytic system were setup, which serving as a good foundation for the development of the industrial equipments. The anatase TiO₂ single crystal nanowires catalyst has been synthesized successfully in this study. By using XRD, XPS, SEM, TEM, HRTEM and other technology on the crystal structure, band, surface morphology and particle size characteristics of the catalyst have been analyzed through XRD, XPS, SEM, TEM, HRTEM and other technology. the analysis results show that titanium dioxide nanowires obtained as anatase single crystal or wire body, synthetic titania has high catalytic activity as much of P25, easy to recycle, and no significant decline of catalytic efficiency after circulation.The test results show that the effective treatment of organic wastewater with no obvious selectivity was obtained by using the synthesized titanium dioxide nanowires photocatalytic. The treated oil effluent has a reduced COD as low as to Level I or less of the emissions standard in "Integrated Wastewater emission standards " GB8978-1996?1999 Partial Amendment?. BTEX could be removed effectively by using photocatalytic titanium dioxide nanowires. When the reaction time was performed 6 h, the benzene concentration in wastewater was decreased to 72.35 ?g/L. Meanwhile, the BTEX removal efficiency also reached up to 95%. Therefore, the treated effluent could fully meets the highest emission concentration limit of the second type of pollutants in "Integrated Wastewater Discharge Standard" GB8978-1996?1999 partial revision?.