TiO_(2)/CeO_(2)复合材料的制备及光催化耦合芬顿氧化处理模拟油田返排液

Preparation of TiO_(2)/CeO_(2) composite and its application in treating simulated oilfield flowback fluid by photocatalytic coupling Fenton oxidation

采用溶胶-凝胶法制备TiO_(2)/CeO_(2)复合半导体光催化剂。通过XRD、TEM表征证明成功制备出TiO_(2)/CeO_(2)催化剂。TiO_(2)/CeO_(2)复合光催化剂与纯TiO_(2)相比,其吸收边向可见光红移,光响应性能更好。用瓜尔胶溶液模拟油田压裂返排液研究所制备的催化剂在光催化和光催化耦合芬顿氧化反应中的催化性能。实验表明,当氧化铈质量分数占复合光催剂的10.19%时(TiO_(2)/CeO_(2)-10.19%),所制备的复合光催化剂催化效率最好。耦合反应中,TiO_(2)/CeO_(2)-10.19%催化剂在4 h内的降解效果远大于纯光催化剂。稳态荧光测试表明,复合CeO_(2)之后,催化剂的荧光强度下降,归因于形成的异质结降低了光生载流子的复合效率。活性物质捕获测试表明,羟基自由基是光催化和耦合反应的主要活性物种。

TiO_(2)/CeO_(2) composite photocatalysts were prepared by sol-gel method and identified by XRD and TEM.Compared with pure TiO_(2),TiO_(2)/CeO_(2) composite photocatalysts transit its absorbance towards visible light and show better response to light.Catalytic performance of the as-prepared photocatalysts in photocatalysis and photocatalytic coupling Fenton oxidation was studied during guar solution simulated oilfield fracturing flowback fluid.The results show that the best catalytic activity of the composite photocatalyst was obtained under cerium oxide mass fraction of 10.19%(TiO_(2)/CeO_(2)-10.19%).In the coupling reaction,the degradation efficiency of TiO_(2)/CeO_(2)-10.19%in 4 h is much higher than that of pure TiO_(2).Steady-state fluorescence test shows that the fluorescence intensity declines after introducing CeO_(2),which can be attributed to that the heterojunction between TiO_(2) and CeO_(2) reducing the recombination efficiency of photogenerated carriers.Radicals scavenging test results show that·OH is the main active species for photocatalysis and the coupling degradation reaction.