TiO2光催化氧化气相甲醛暾研究进展

室内多种建筑材料释放出的甲醛，对人类的生存危害极大。因此，用TiO2光催化剂降解气相甲醛成为一个研究热点。文章回顾了近年来用TiO2光催化剂降解气相甲醛取得的成果。     

纳米SiO2／TiO2光催化降解空气中甲醛的研究

采用共沉淀方法制备了Si共掺杂的SiO2／TiO2光催化复合粉末,将其负载于活性炭（ACF）上。在流动化床中,考察了煅烧温度、煅烧时间、Si掺杂量、负载次数、光照条件以及甲醛初始浓度对该复合剂光催化降解甲醛效率的影响。结果发现当Si：Ti：1：4、SiO2／TiO2复合催化剂煅烧时间4h、煅烧温度400℃,ACF上负载1次,18w紫外光照射时,甲醛的降解效果最佳,对初始浓度小于0．4mg／L的甲醛气体,降解率可达90％左右。     

TiO_2薄膜制备条件对甲醛光催化降解性能的影响

以钛酸丁酯为前驱体,用溶胶-凝胶法制备了TiO2薄膜,并进行了甲醛的光催化降解实验,考察了制备条件对光催化降解性能的影响。结果表明,适宜的制备工艺条件为:溶胶体系pH=3,溶胶配方中V(钛酸丁酯)∶V(无水乙醇)∶V(水)∶V(冰醋酸)=5∶34∶2∶2,干溶胶在600℃下活化5h,制成的薄膜光催化降解甲醛降解率大于50%。     

TiO_2光催化降解甲醛影响因素的研究进展

在全面分析国内外近几年来TiO2光催化降解甲醛的研究成果基础上,从催化剂、紫外光、甲醛气体和反应条件四个方面归纳出了影响催化活性的主要因素。详细讨论了各种因素的影响情况,最后提出了推进甲醛光催化降解反应活性的建议。     

光催化降解甲醛的纳米二氧化钛的合成

以TiC l4为前躯体,合成了光催化降解甲醛的纳米TiO2。以甲醛的光催化降解性能为指标,采用正交实验法研究了纳米二氧化钛的合成条件。结果表明,最佳合成工艺为:以盐酸为溶剂,Ti4+∶SO42-(摩尔比)=2∶1,pH值为9,煅烧温度为600℃。在此条件下制备的TiO2具有很好的光催化活性,2 h内甲醛的降解率达到85.8%。     

纳米TiO_2光催化氧化降解双酚A研究

本文利用纳米TiO2光催化氧化技术降解双酚A,探讨了pH,紫外光强,催化剂投加量等因素对双酚A降解程度以及TOC的影响。结果表明,纳米TiO2光催化氧化降解双酚A在碱性条件下降解程度比在中性和酸性条件下要高;随着紫外光强,催化剂用量增加提高。降解最终TOC浓度也随着紫外光强和催化剂投加量增加而下降。     

光催化降解甲醛的波长效应研究

分别以紫外杀菌灯和黑光灯为光源，研究了TiO2薄膜催化剂上甲醛的光催化氧化反应．实验结果表明，紫外杀菌灯照射下，甲醛的光催化降解率明显低于以黑光灯为光源时甲醛的光催化降解率．采用傅立叶红外光谱(FT-IR)和热分析(TG-DTA)对反应后的TiO2光催化剂进行分析和表征，对两种不同光源照射下甲醛光催化降解率的差异进行了初步探讨．     

具有纳米结构的TiO_2纤维光催化氧化活性

研究了具有纳米结构,高比表面的锐钛矿TiO2纤维在光催化降解苯酚体系中的氧化性能,发现其活性与P25相当;通过加羟基自由基猝灭剂证实了羟基自由基(HO.)对苯酚降解的贡献;而通过加空穴猝灭剂则观察到明显的空穴(h )效应。并通过K I氧化反应进一步研究了催化剂表面上的空穴效应,结果表明,TiO2纤维上的光生空穴比P25稳定,其空穴量子产率是后者的3.3倍。     

TiO2光催化降解室内甲醛的应用

TiO2作为高效的催化剂具有的众多优点已经为人熟知,但目前市场上应用于人们日常生活中的产品还比较少,文章讨论的就是TiO2降解室内甲醛可能出现的各种形式,包括其在自洁玻璃、灯具、空调和涂料方面的应用,并对其未来的发展做了简单展望。     

载银活性炭负载TiO_2对甲醛的吸附降解性能研究

以载银活性炭颗粒负载TiO2作催化剂,在紫外光照射下降解甲醛气体,考察了微波特殊场处理、紫外光光强、TiO2负载量及反应时间等主要因素对甲醛光催化降解率的影响,并考察了催化剂在反复使用后的失活情况。     

Photocatalytic oxidation of propene at low concentration

The present paper analyses the preparation and characterisation of different titanium dioxide-based photocatalysts for propene oxidation at low concentration. Special attention has been paid to the agglomeration of the photocatalysts in form of pellets, to the study of the effect of introducing some carbonaceous materials into the catalyst composition and to comparison with commercial photocatalysts. Our results show that P25 exhibits the best activity among all the studied materials. However, activity importantly decreases when agglomerating the photocatalysts in form of pellets, either with or without carbon addition. The type of carbon material used in the photocatalyst strongly affects propene activity. Thus, carbon materials combining high surface area and high electric conductivity enhance the photocatalyst performance and photocatalyst pellets have been prepared exceeding the activity of a carbon-containing commercial photocatalyst. The importance of the UV-source has been highlighted, showing the 257.7 nm peak radiation much better results than the 365 nm UV-light. The studied photocatalysts are very interesting for propene oxidation not only because of their high activity, but also because it remains constant for more than 40 h and total mineralization of the oxidised propene to carbon dioxide and water is achieved.     

Photocatalytic activity of TiO2 coated porous silica beads on degradation of cumene hydroperoxide

Recently, due to an increasing global concern on environmental safety, titanium dioxide (TiO₂) photocatalyst has been extensively researched for use as air and water pollution treatments. This study was initiative for producing an economically viable TiO₂ photocatalyst material with recyclability for degradation of CHP contaminated wastewater. TiO₂ P‐25, a well‐known photocatalyst, with a proper amount (15% w/w of CAC) was coated on porous silica beads (ECOLITE^®) by granulation technique, using high calcium aluminate cement (CAC) as a binder (EC+CAC+15% w/w TiO₂ P‐25). The experiments revealed that high concentration CHP solutions were completely degraded by EC+CAC+15% w/w TiO₂ P‐25 within 5 and 7 hours. The recyclability of EC+CAC+15% w/w TiO₂ P‐25 was evaluated by investigation the degradation activity of freshly prepared CHP solution under UV light irradiation using the repetitive photocatalyst beads for 6 runs. HPLC analyses indicated that the CHP degradation was completed in the 1^st run and down to over 90% in the 6^th run. Hence, EC+CAC+15% w/w TiO₂ P‐25 showed a long durability and good recyclability for CHP degradation, resulted from the good adherence of hydration product layer of CAC for TiO₂ particles as well as its large surface area that offered good adsorption for CHP.     

改性TiO2催化剂光催化氧化脱硫

采用溶胶-凝胶法制备过渡金属改性纳米TiO2催化剂并进行了表征,用于FCC汽油模型含硫化合物脱硫。考察了TiO2的用量、四丁基溴化铵的用量以及Fe、Ni、Cu、Zn掺杂量对脱硫效果的影响。结果表明,FCC汽油与甲酸体积比为1∶1、7.5%(mol)Ni-TiO2 20 mg、加入5 mg四丁基溴化铵、光照3 h条件下,脱硫率最高达到98.4%。     

CoPcS/TiO_2/beads及TiO_2/beads光催化降解水面漂浮植物油

以钛酸四丁酯为原料,以空心玻璃微珠为载体,采用溶胶-凝胶法制备出TiO2/beads光催化剂,用浸渍法制备出CoPcS/TiO2/beads光催化剂。研究了TiO2/beads及CoPcS/TiO2/beads光催化降解水面漂浮植物油的最优条件。结果表明,酸性或中性条件下,375 W中压汞灯照射2~3 h,TiO2/beads与CoPcS/TiO2/beads的投加量分别为3 g与1 g时,植物油的去除率达90%以上,投加微量的H2O2,可大大提高两者的光催化去除率。     

纳米TiO_2光催化氧化处理糠醛废水的研究

以钛酸丁酯为原料,采用溶胶凝胶法制备的TiO_2被用于处理糠醛废水.研究结果表明:pH=2～6的150 mL废水中加入0.06 g TiO_2和3 mL ClO_2或H_2O_2,在不断搅拌下,紫外光照65 min,COD去除率可达到67%.此光催化氧化反应分两个阶段,均符合一级反应动力学规律:R=1.391 2t(t=0～30min).R=0.4349t+29.342(t=30～75 min).而且TiO_2催化剂重复使用15次的光催化效果没有变化,为TiO_2光催化氧化处理糠醛废水工业化应用提供了技术支撑.     

负载型光催化膜降解高浓度甲基橙溶液

以负载型TiO2/活性炭光催化膜降解高浓度甲基橙水溶液为处理体系,研究了负载膜型与微粉型光催化剂降解活性,考察了催化剂用量、溶液初始质量浓度、溶液pH值等对降解性能的影响。探讨了初始质量浓度对降解反应动力学的影响,确定了降解反应级数为一级,得出了不同初始质量浓度下的反应半衰期表示式。     

Photocatalytic activity of TiO2 nanotube layers coated with Ag and Pt

Abstract

Abstract

Thin films of anatase TiO₂ nanotube arrays (TiO₂ NTs) were prepared in this study. Pt and Ag were coated on the TiO₂ NTs films, which intend to increase the photocatalytic activity under ultraviolet-visible (UV-vis) irradiation. The phase and structure of the films were investigated by X-ray diffraction and scanning electron microscopy. Photocatalytic activity was tested by UV-vis absorption spectroscopy and showed that UV-vis light absorption of the films was remarkably improved by coated Ag and Pt by 72% and 183% respectively. The photocatalytic activities of the films towards degraded methyl orange and HCHO were compared and were all found to follow the sequence Pt/TiO₂ NTs>Ag/TiO₂ NTs>TiO₂ NTs. It was also found that the kinetics of HCHO photocatalytic degradation by the films fits the first order reaction model better and has higher efficiency than that of the methyl orange photocatalytic degradation by the same films.     

O2对铁掺杂玻璃纤维负载TiO2光催化降解苯酚的影响

采用三价铁对TiO2进行掺杂改性,并以玻璃纤维为载体,将改性后的TiO2负载到其表面,形成光催化反应填料,以高压汞灯为光源,进行水中苯酚的光催化降解,反应过程中引入O2,以促进水中HO.的生成,重点考察了O2的引发作用对光催化氧化的影响。结果表明,O2的加入对HO.的产生有显著的引发作用,可明显提高光催化效率。在(UV365)250 W光源照射下,pH值为3～5,O2通入量1.0 L/(min.L),反应器内上升流速为0.7 m/min等实验条件下,初始浓度为30 mg/L的苯酚废水,经120 min光催化反应后,其矿化率可达83%以上。     

Catalytic oxidation of low concentration formaldehyde over Pt/TiO2 catalyst

Formaldehyde(HCHO) is an important indoor pollutant.Catalytic oxidize low concentration HCHO is an effective way to eliminate indoor pollution.In this study,a series of Pt/TiO_2 catalysts are prepared by impregnation and reduced by NaBH_4.The effects of loading amount of Pt and cry stal type of TiO_2 on the physical and chemical properties and the catalytic performance in HCHO oxidation reaction are investigated.The results show that the quantity of active site and the oxygen vacancy of catalysts increa sed with increasing Pt content,which is beneficial to promote the further performance of catalysts.Nevertheless,with the further rises of Pt content,the specific surface area further decreases,and the proportion of Pt~(2+) species on the catalyst surface which is significant to catalytic properties also decreases,causing catalytic performance decreases.Compared with the catalyst supporting on rutile,the Pt/α-TiO_2 catalyst supporting on anatase has larger specific surface area,more Pt~(2+) phase and easier to form oxygen vacancy in the support,which cause better catalytic performance.The catalyst with Pt content of0.1 wt% and supported by anatase TiO_2 has the best catalytic performance.The HCHO conversion efficiency reaches 98% and 100% at 50℃ and 100 ℃, and the stabilization time is longer than 140 h.     

二氧化钛光催化降解处理水溶性甲醛的研究

以TiO2为光催化剂,在自制光催化反应器中研究了紫外光源对甲醛废水进行光催化降解的可行性。结果表明,甲醛浓度在40 mg/L,其最佳工艺条件为:反应pH为7,TiO2锐钛矿与金红石晶型比为1∶1,5 g/L的TiO2催化剂投加量,采用λ=350~400 nm紫外灯作为光源。同时,TiO2催化剂有较好的回收利用性能。