纳米晶TiO_2光催化降解制浆黑液的影响因素

Influencing Factors of Photocatalytic Degradation of Pulping Wastewater on Nanocrystal Semiconductor TiO_2

用溶胶—凝胶法制得TiO2粉末,并对其进行热处理。该粉末是一种纳米晶半导体金属氧化物。用该粉末作光催化剂,以高压汞灯为紫外光源,对制浆黑液进行降解处理。将实验中废水的CODcr、色度、脱色率及pH值等参数的变化作为评价光催化降解效果的依据。结果表明,TiO2用量和氧流量均有一个最佳值。催化剂的用量过低,光源的能量得不到充分利用,过高则无助于光子的吸收,反而因过多的光散射而降低效率。氧流量过低则不能有效移除催化剂中的光生电子,使催化剂的催化能力得不到充分发挥,过高则多余的氧不能参与反应。另外,降解反应的速度与废水中有机物的初始浓度无关。

The metal oxide semiconductor, nanocrystal titania was prepared by Sol-Gel method and this titania was undergone a certain heat treatment. In the presence of this titania, pulping wastewater was irradiated by ultraviolet to purify it. During experiments these parameters of reacting systems were determined including CODcr, chroma, and rate of decolorization. The results suggest that there is a best value about both dosage of titania which is used as photocatalyst in reacting system and flux of oxygen with which liquid of reactants was bubbled during illumination by ultraviolet. The rate of reaction dose not relate to concentration of organic contamination in wastewater.