TiO_2的低温制备及其对有毒有机污染物的降解

Low-Temperature Preparation of TiO_2 and Photodegradation of Toxic Organic Pollutants

溶胶水热法制备了TiO2粉末,用X射线衍射仪(XRD)、比表面积及孔径分析仪(BET)和透射电镜(TEM)对TiO2进行了初步表征,结果显示:纳米TiO2主要为锐钛矿相(含板钛矿相(121)),比表面积为106.2 m2/g.在紫外光(λ≤387 nm)照射条件下,以有机染料罗丹明B(Rhodamine B,RhB)和无色小分子2,4-二氯苯酚(2,4-dichlorophenol,2,4-DCP)的紫外光(λ≤387 nm)光催化降解试验为探针反应,低温(50℃)下制备的TiO2粉末具有较高光催化活性,对RhB和2,4-DCP有较好的降解效果.通过分析紫外-可见光谱(UV-Vis)、红外光谱(FTIR)和总有机碳(TOC)测定,发现TiO2/UV体系能使RhB和2,4-DCP发生有效的降解,反应5 h后RhB和7 h后2,4-DCP的矿化率分别达到81.2%和86.8%.同时,采用辣根过氧化物酶(POD)、N,N-二乙基对苯二胺(DPD)分光光度法和苯甲酸荧光光度法分别测定了在降解过程中H2O2和羟基自由基(.OH)的变化,表明TiO2光催化机理涉及到.OH历程.

TiO2 particles were prepared under low-temperature conditions by sol-hydrothermal-stesrn method. The characteristics of TiO2 were carried out using XRD, BET, TEM. The results showed the basic structure of product was mainly anatase phase with the existence of brookite phase （121）） and the BET was 106.2 m^2/g. The photo-catalytic degradation under UV light （λ≤387 nm） of organic dye Rhodamine B（RhB） was used as probe reactions to evaluate the optimum TiO2. TiO2 prepared under low-temperature conditions had a better degradation effect to RhB and 2,4-DCP, which were significantly degradated in TiCh/UV（λ≤4387 nm） system by analysing UV-vis spectroseopy, FTIR and TOC. After 5 h and 7 h the mineralized rate of RhB, 2,4-DCP was 81.2%, 86.8 %, respectively. N, N-diethyl-p-phenylenediamine （DPD）, Horseradish peroxidase （POD）, spectro-photometry and benzoic acid spectro-fluorescence analysis method were used to detect hydrogen peroxide（H202） and hydrogen radicals（·OH）. The experiment results indicated that photocatalysis degradation of TiO2 mainly referred to ·OH radical mechanism.