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采用溶胶-凝胶法制备了稀土La掺杂Ti O2纳米粉末,利用X射线衍射(XRD),紫外-可见漫反射光谱(UV-Vis DRS)、透射电镜(TEM)和荧光光谱(PL)等分析方法对所制备样品进行表征;以亚甲基蓝和石化二级出水作为降解对象,研究了La掺杂Ti O2样品的光催化性能。表征结果显示,本实验所制备的Ti O2样品均为锐钛矿晶型;稀土La掺杂可以使样品的晶粒尺寸由25 nm减小为15 nm;同时可改善样品的团聚现象;并可促进样品对可见光的吸收;此外还具有降低电子-空穴的复合,提高Ti O2量子效率的作用。光催化降解亚甲基蓝实验结果显示,当La掺杂含量为0.50%时,样品的光催化性能最佳;优选0.50%La-Ti O2对石化二级出水进行光催化降解反应,结果显示光催化反应180 min时,二级出水中的COD和UV254的降解率分别可达55%和70%以上;且经过3次回用后降解率未明显下降,说明本实验所制备的实验样品具有良好稳定的光催化性能,这为光催化深度降解石化二级出水工业应用提供了可能。
The rare earth La-doped Ti O2 nano-powders were prepared by sol-gel method and characterized by X-ray diffraction (XRD), UV-Vis DRS, transmission electron microscopy (TEM) and fluorescence spectroscopy (PL) Analytical methods were used to characterize the prepared samples. Methylene blue and petrochemical secondary effluent were used as degradation targets to study the photocatalytic activity of La-doped Ti O2 samples. The characterization results show that the Ti O2 samples prepared in this experiment are all anatase. The rare-earth La doping can reduce the grain size from 25 nm to 15 nm and improve the sample agglomeration. Promote sample absorption of visible light; In addition, it also has the effect of reducing the electron-hole recombination and increasing the quantum efficiency of Ti O2. The results of photocatalytic degradation of methylene blue showed that the photocatalytic activity of the sample was the best when the content of La was 0.50%. The photocatalytic degradation reaction of the petrochemical secondary effluent with 0.50% La-Ti O2 was the best. The results showed that photocatalytic reaction 180 min, the secondary effluent COD and UV254 degradation rate of up to 55% and 70% respectively; and after 3 times the reuse did not significantly reduce the degradation rate, indicating that the experimental sample prepared in this experiment has a good and stable photocatalytic Performance, which photocatalytic degradation of petrochemical secondary effluent industrial applications have made it possible.