光电催化技术处理油田难降解有机废水OA

In view of the low removal efficiency of refractory organic compounds such as phenol and sodium benzenesulfonate in discharged wastewater from oilfields,CdS/TiO2 composite catalysts were prepared via the hydrothermal method.A high-efficiency photoelectrocatalytic(PEC)system was constructed,and the process parameters was optimized.Experimental results show that the degradation rate of chemical oxygen demand(COD)reaches 72.5%within 90 min of reaction under the conditions of 1.4 V bias potential,pH=7.0,and oxygen aeration rate of 40 mL/min for the CdS/TiO2 composite catalyst in the PEC system.The dissolution amount of Cd2+is below the detection limit,indicating that photocorrosion is effectively inhibited.In addition,no obvious decrease in the catalytic activity of CdS/TiO2 composite catalyst is found after 5 cycles of reuse.The main active species for the degradation of refractory organic compounds by CdS/TiO2 composite catalyst in the PEC system are h+and·OH,while the contribution of·O2-is relatively small.Under visible light irradiation,the type Ⅱ heterojunction accelerates the separation of photogenerated e--h+pairs.e-is captured by oxygen to generate·O2-,and h+are oxidized to form·OH.Finally,refractory organic compounds are oxidatively degraded through the combined action of h+and·OH.