Zr/TiO2纳米颗粒的制备及其光催化活性

以钛酸丁酯,乙醇为原料,用固相合成法制备了Zr/TiO2纳米颗粒,用XRD、TEM对其组成、颗粒大小、形貌进行了表征.通过对罗丹明B的降解反应,考察了Zr/TiO2的光催化活性.结果表明,Zr/TiO2为纳米颗粒,平均粒径为12.7 nm左右,且颗粒均匀;掺杂金属离子Zr提高了TiO2光催化效率,掺杂2.0%Zr的催化剂活性最高.Zr/TiO2的光催化反应,首先是反应物在Zr/TiO2表面发生吸附作用,然后进一步发生光催化降解.     

负载型TiO2固定相光催化氧化法降解水中呋码唑酮

以高压汞灯为光源、负载在海砂上的ＴｉＯ２为催化剂，采用敞口固定床型光催化反应器对水中难降解的呋码唑酮（ＦＴＤ）进行了固定相光催化氧化实验。结果表明，反应速率可用ＬａｎｇｍｕｉｒＨｉｎｓｈｅｌｗｏｏｄ方程描述，与光分解相比，光催化氧化的突出优点是矿化程度高，相同光辐射条件下反应１００ｍｉｎ，０．１０ｍｍｏｌ／Ｌ的ＦＴＤ水溶液经光催化氧化后ＴＯＣ的去除率为８９．１％，而经光分解后ＴＯＣ的去除率仅为２８．８％；在反应体系中投加少量臭氧或过氧化氢可以显著提高ＦＴＤ的氧化效率，说明光催化氧化可以兼容Ｏ３／ＵＶ、Ｈ２Ｏ２／ＵＶ等光激发氧化工艺。制得的负载型ＴｉＯ２具有较高的机械强度和化学稳定性，可重复利用。探讨了充氧、ＦＴＤ浓度及ｐＨ值等对光催化氧化过程的影响。     

膨胀珍珠岩负载TiO2光催化脱色性能的研究

以钛酸四丁酯为原料 ,膨胀珍珠岩为载体 ,用溶胶 -凝胶法制备可漂浮于水面的负载型TiO2 。利用该负载型TiO2 对罗丹明B(RB)进行光催化脱色实验 ,结果表明 ,浸渍 3次的负载型TiO2 光催化活性最高 ,催化剂最佳用量为 5 0 0mg/10 0mLRB ,经 5h光照 ,对 10 0mL浓度为 1mg/L和 2 .5mg/LRB脱色率分别为 76 .6 7%和 4 7.2 7% ;该催化剂使用寿命长 ,2 5h后催化剂脱色性能没有减弱 ,可重复使用 ;经 8h光照 ,染料废水脱色效果好。     

附载型复合光催化剂TiO2·SiO2/beads降解有机磷农药

研究以四异丙醇钛 [Ti( iso- O C3 H7) 4]、硅酸乙酯为原料 ,以空心玻璃微球为载体 ,用溶胶—凝胶法制备可漂浮附载型复合光催化剂 Ti O2 · Si O2 / beads的过程 ,利用附载型复合光催化剂降解有机磷农药。结果表明 ,复合型光催化剂 Ti O2 · Si O2 摩尔比存在最佳值 ,n ( Ti O2 ) / m ( Si O2 ) =30 / 70时 ,光催化剂活性最高 ,其活性是同样降解条件下、同样含量 Degussa P- 2 5Ti O2 的 2倍左右。该光催化剂比表面大 ,吸附性强。并用 XRD和 SEM对附载型复合光催化剂进行表征     

有机污染物的光催化降解过程中的分析技术进展

本文对有机物的光催化降解动力学研究 ,降解产物的鉴定、定量检测等过程中所使用的一些分析技术和手段 ,尤其是在有机物的光降解机理研究中羟自由基的检测技术和方法进行了综述     

负载型纳米TiO2光催化降解水中微量溶解性间二甲苯

以高压汞灯为光源 ,采用浸涂 -烧结法制备的负载型纳米TiO2 作为光催化剂 ,通过对水中微量溶解性间二甲苯的光催化氧化过程的研究表明 ,初始浓度在 6 .6 8— 17.36mg/L的范围内 ,间二甲苯的光催化反应遵循表观一级反应动力学规律 ,反应的表观速率常数随溶液初始浓度的增大而减小 ,半衰期则随初始浓度的增大而增加 ,经 1.5h反应后 ,溶液中间二甲苯的去除率从 17.36mg/L的 5 4 .4 4 %增加到 6 .6 8mg/L的 75 .90 %。     

Effects of TiO2 nanoparticles on the aquatic plant Spirodela polyrrhiza: Evaluation of growth parameters, pigment contents and antioxidant enzyme activities

Plants are essential components of all ecosystems and play a critical role in environmental fate of nanoparticles. However, the toxicological impacts of nanoparticles on plants are not well documented. Titanium dioxide nanoparticles (TiO₂-NPs) are produced worldwide in large quantities for a wide range of purposes. In the present study, the uptake of TiO₂-NPs by the aquatic plant Spirodela polyrrhiza and the consequent effects on the plant were evaluated. Initially, structural and morphological characteristics of the used TiO₂-NPs were determined using XRD, SEM, TEM and BET techniques. As a result, an anatase structure with the average crystalline size of 8nm was confirmed for the synthesized TiO₂-NPs. Subsequently, entrance of TiO₂-NP_S to plant roots was verified by fluorescence microscopic images. Activity of a number of antioxidant enzymes, as well as, changes in growth parameters and photosynthetic pigment contents as physiological indices were assessed to investigate the effects of TiO₂-NPs on S. polyrrhiza. The increasing concentration of TiO₂-NPs led to the significant decrease in all of the growth parameters and changes in antioxidant enzyme activities. The activity of superoxide dismutase enhanced significantly by the increasing concentration of TiO₂-NPs. Enhancement of superoxide dismutase activity could be explained as promoting antioxidant system to scavenging the reactive oxygen species. In contrast, the activity of peroxidase was notably decreased in the treated plants. Reduced peroxidase activity could be attributed to either direct effect of these particles on the molecular structure of the enzyme or plant defense system damage due to reactive oxygen species.     

Influences of working pressure on properties for TiO2 films deposited by DC pulse magnetron sputtering

TiO2 films were deposited at room temperature by DC pulse magnetron sputtering system.The crystalline structures,morphological features and photocatalytic activity of TiO2 films were systematically investigated by X-ray diffraction (XRD),atomic force microscopy and ultraviolet spectrophotometer,respectively.The results indicated that the working pressure was the key deposition parameters influencing the TiO2 film phase composition at room temperature,which directly affected its photocatalytic activity.With increasing the working pressure,the target self-bias decreases monotonously.Therefore,low temperature TiO2 phase (anatase) could be deposited with high working pressure.The anatase TiO2 films deposited with 1.4 Pa working pressure displayed the highest photocatalytic activity by decomposition of Methyl Orange solution,which the degradation rate reached the maximum (35%) after irradiation by ultraviolet light for 1 h.     

纳米TiO_2/SiO_2复合颗粒催化性能研究

为了提高纳米TiO2粒子的光催化性能和可回收性,采用溶胶-凝胶法制备了纳米TiO2/SiO2复合颗粒。利用XRD与比表面积测试仪,考察了热处理温度对复合颗粒的比表面积和其中纳米TiO2的粒度与晶型的影响情况,发现纳米TiO2的锐钛矿型转变温度由常规的350℃升高到600～700℃。研究了不同热处理温度的复合颗粒、不同Ti/Si比及其添加量对其光催化性能的影响,发现700℃下热处理2h,Ti/Si比为1.5的复合颗粒对100mg/mL的甲基橙溶液的光催化性能最好,其最佳使用量仅约为1.5g/L。