纳米TiO_2/SO_4^(2-)的合成及光催化降解性能研究

Synthesis of nano-TiO_2/SO_4^(2-) and study on its photocatalytic degradation activity

研究了以工业级钛酸异丙酯为前驱体,正丙醇为溶剂,浓硫酸作催化剂和抑制剂,乙酰丙酮为稳定剂,采用溶胶-凝胶法制备纳米TiO2/SO42-。利用XRD、SEM、FT-IR、UV-vis、N2吸附-脱附测定BET表面积对所制备的材料进行了表征。结果表明:纳米TiO2/SO42-催化剂在可见光区的吸收较强,所制备的催化剂与未经改性的TiO2相比,吸收边从350 nm红移到430 nm左右,其红移效果显著。在紫外灯照射下进行了光催化降解亚甲基蓝溶液的催化剂性能研究,探讨了pH值、反应温度、亚甲基蓝初始质量浓度以及催化剂用量对降解率的影响。结果表明:光催化降解亚甲基蓝在中性条件下的降解率较高,碱性环境下达到最佳;最佳反应温度为35~55℃;初始浓度越大降解率越小;处理30 mL亚甲基蓝溶液所需催化剂为30 mg。

TiO2/SO4^2- nano-particles is synthesized by sol-gel method using titanium tetraisopropoxide as the precursor, n-propanol as solvent, concentrated sulfuric acid as catalyst and inhibitor, and acetylacetone as stabilizer. The prepared products are characterized by XRD, SEM, FTIR, UV-vis, and BET surface area （ by N2 adsorption-desorption）. The results indicate that nanophotocatalysts TiO2/SO4^2- shows intense absorption in the visible range and evident red shifts of absorption edge of TiO2/SO4^2- happenes from 380 nm in the UV range to 430 nm in the entire visible region compared to pure TiO2. The photocatalytic degradation of methylene blue is car- ried out under UV light irradiation. The effects of pH value, reaction temperature, initial concentration of methylene blue and the a- mount of catalyst on the degradation rate are discussed. The results show that the efficiency of photocatalysts photodegradation of meth- ylene blue in the neutral condition has a higher rate, and the efficiency of degradation achieves the best in an alkaline condition ; reac- tion temperature range of 35 -55℃ is appropriate; the lower the degradation rate the higher the initial concentration is; 30mg catalysts is the best for 30mL methylene blue solution.