Preparation and photocatalytic properties of Fe-doped TiO_2 nanoparticles

1　INTRODUCTIONAsagoodphotocatalyst ,TiO2 hasattractedex tensiveinterestduetoitsvariousexceedingpropertieswithalargesurfacearea ,nontoxicity ,highstability ,lowcost ,andhighcatalysisforchemicalwastetreat ment[1] .PhotocatalyticreactionsoccuronthesurfaceofTiO2 particles .Whenaphotonwithenergyhve qualtoorexceedingtheTiO2 energygap(Eg =3.2eV ,λ=387nm)isabsorbedbyaTiO2 particle ,electron holepairswillbegenerated ,whichcanre duceandoxidatethepollutantsinbothwaterandair .Itisgenerallybelie…     

Preparation of titanium dioxide from titania-rich slag by molten NaOH method

Preparing titanium dioxide from titania-rich slag(TiO2 73wt%) by molten NaOH method has been developed.The effects of tem-perature and reaction time on the titanium conversion were investigated.The results showed that temperature had significant influence on the titanium conversion as well as the structure of the product.About 92% of titanium in the titania-rich slag could be converted after reacting with NaOH at 500℃ for 1 h.Metatitanic acid was formed through the steps of washing treatment,acid dissolution,and hydrolysis.Well-dispersed spherical titanium dioxide particles with an average size of 0.1-0.4 μm can be obtained by calcination of metatitanic acid.In addition,the content of titanium dioxide in the product is up to 98.6wt%,which can be used as pigments after further treatment of coating and crushing.     

Preparation and photocatalytic properties of Fe-doped TiO2 nanoparticles

Nanocrystalline Fe-doped TiO2 with size of 60-70 nm was prepared by a sol-gel technique, followed by freeze-drying treatment for 2 h. Thermogravimetric and differential thermal analyses, X-ray diffraction, scanning electron microscope, laser diffraction particle size analyzer and OV-Vis spectrophotometer technologies were used to characterize the product. The photocatalytic activities of the samples were evaluated by the degradation of wastewater of paper-making. The effects of Fe ion implantation on the photocatalytic activity of TiO2 were also dis-cussed. The results show that the iron content plays an essential role in affecting the photocatalytic activity of the Fe-doped TiO2 and the optimum content of Fe-doped is 0.05% (mass fraction). The photocatalytic activity of sam-ples with lower content of Fe-doped is higher than that of pure TiO2 in the treatment of paper-making wastewater.The photo-degradation effect of paper-making effluent is the best by means of Fe-doped TiO2 with 0.05 % Fe.     

钒钛高炉渣中金属铁的分析

研究和提出了以碘-乙醇分离金属铁,EDTA络合滴定法测定钒钛高炉渣中金属铁的新方法．所用方法简单,试剂无毒,分析结果重现性好,平均标准偏差为0．02％,准确度较高,平均回收率达99．55％,适合于钒钛高炉渣、普通炉渣中金属铁的测定．     

Preparation of CaO-Al2O3-SiO2 system glass from molten blast furnace slag

To use the potential heat of molten blast furnace slag completely, a CaO-Al2O3-SiO2 system glass （MSG） was prepared from the molten industrial slag. The corresponding method proposed in this study utilized both slag and its potential heat, improving the production rate and avoiding the environmental pollution. Using appropriate techniques, an MSG with uniform color and superior performances was produced. Based on the experimental results and phase diagram, the chemical composition of MSG by mass is obtained as follows：CaO 27%-33%, SiO2 42%-51%, Al2O3 11%-14%, MgO 6%-8%, and Na2O＋K2O 1%-4%. Thermodynamic processes of MSG preparation were analyzed, and the phases and microstructures of MSG were investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results show that alkali metal oxides serve as the fluxes, calcium oxide serves as the stabilizer, and alumina reinforces the Si-O network. XRD and SEM analyses show that, the prepared MSG displays the glass-feature patterns, the melting process is more complete, and the melt viscosity is lowered with an increase in calcium oxide content;however, a continuous increase in slag content induces the crystalli-zation of glass, leading to the formation of glass subphase. The optimum content of molten slag in MSG is 67.37wt%. With respect to bend-ing strength and acid/alkali resistance, the performance of MSG is better than that of ordinary marble.     

由含钛高炉渣合成复合肥初探

以含钛高炉渣作为主要原料,采用加热法制备复合肥,以提高其溶解性能,使其中的营养元素转化为易被植物吸收利用的形式．考察了工艺条件对肥料溶解性能的影响．结果表明,合成复合肥的适宜工艺条件为：硫酸铵与含钛高炉渣的质量比为8：1,加热温度为300℃,恒温时间为30min．复合肥中含有氮、硅、硫、钙、镁、铁和钛等营养元素,其中氮、硫、镁、铁和钛以水溶性物质的形式存在;硅和钙以枸溶性物质的形式存在,均可被植物有效利用．     

Kinetics of the leaching of TiO2 from Ti-bearing blast furnace slag

Ti-bearing blast furnace slag is a valuable secondary resource containing about 24 percent of TiO2. In this paper a process of leaching Ti-bearing blast furnace slag with sulfuric acid to recover TiO2, and the kinetics of that reaction, are described. Under laboratory conditions the rate is controlled by a chemical reaction. The leaching reaction is in accord with a shrinking un-reacted-core model. The apparent reaction order of the leaching reaction was 1.222 and the apparent activation energy was 87.01 kJ/mol. The model fits the observed data well until 90% of the TiO2 has be leached from the particles. The model disagrees with observations during later periods of the reaction because the solution becomes supersaturated with Ti ions, which precipitate as H2TiO4. The assumptions of constant reactant concentration and that there is no effect from the product layer on diffusion, also cause the model to deviate from the actual values.     

稀土掺杂对TiO_2薄膜光催化性能的影响

用溶胶-凝胶法于玻璃表面分别制备了镧、铈掺杂纳米TiO2薄膜,采用X射线衍射仪(XRD)、原子力显微镜(AFM)对其结构和形貌进行了表征,并通过对紫外光照射下亚甲基蓝溶液的光催化降解率评价其光催化性能,研究了不同掺杂量、热处理温度对镧、铈掺杂纳米TiO2薄膜光催化性能的影响,探讨了其光催化影响机制.研究发现:镧掺杂可以抑制由锐钛矿相向金红石相的转变,并且镧、铈掺杂纳米TiO2薄膜都存在最佳热处理温度和最佳掺杂浓度.     

TiO_2-SiO_2复合气凝胶涂层的制备和光催化性能

利用TiCl4和工业水玻璃为原料,通过溶胶凝胶法制备TiO2-SiO2复合凝胶,用三甲基氯硅烷(TMCS)/乙醇(EtOH)/正己烷(Hexane)混合溶液对湿凝胶进行改性,常压干燥制备了TiO2-SiO2气凝胶,经150℃干燥所得的气凝胶具有多孔结构,获得的气凝胶比表面积达到646～816m2/g,孔体积达到1.52～2.19cm3/g。用乙醇作为分散剂,将气凝胶块体研磨成具有一定黏度的浆料,采用丝网印刷法制成TiO2-SiO2复合气凝胶涂层。利用X射线衍射(XRD)、扫描电镜(SEM)和孔径及比表面积分析仪(BET)对复合气凝胶的结构、形貌和孔性质进行了研究,通过分光光度计法分析了TiO2-SiO2复合气凝胶涂层光催化降解罗丹明B的性能,在可见光下照射4h后降解率达到77%。     

Preparation of V-doped TiO2 photocatalysts by the solution combustion method and their visible light photocatalysis activities

A series of nanocrystalline V-doped （0.0-3.0 at.%） TiO2 catalysts have been successfully prepared by the one-step solution combustion method using urea as a fuel. The obtained powders were characterized by XRD, SEM, Raman, XPS and UV-Vis DRS. The effects of V doping concentration on the phase structure and photocatalytic properties were investigated. XRD, Raman, and XPS show that V doping diffuses into TiO2 crystal lattice mainly in the form of V5＋ and causes a phase transition from anatase to mille. V doping can widen the light absorption range of TiO2, with the absorption threshold wavelength shifting from 425 to 625 nm. The photocatalytic activity of V-doped TiO2 powders were evaluated by the photocatalytic degradation of methyl orange （MO） under visible light irradiation. It is found that V doping enhances the photoeatalyilc activity under visible light irradiation and the optimal degradation rate of MO is about 95.8% with 1.0 at% V-doped TiO2.     

量子尺寸纳米TiO2的水热制备及光催化性能

在钛酸丁酯和乙醇体系下,利用水热法制备了平均粒径为4～10 nm的量子尺寸锐钛矿型纳米二氧化钛粉末,并研究了此粉末的光催化活性和晶粒粒径、荧光发射光谱的关系.结果表明: 制备的纳米二氧化钛粉末在粒径为8～9 nm时光催化活性最好,当晶粒粒径再减小以后,由于表面活性的增加导致晶粒表面羟基的增加,成为电子和空穴的复合中心而使活性降低.同时此粉末的荧光发射光谱中并没有发现荧光峰位随着晶粒粒径变小而发生位移,并且荧光发射光谱峰的强度和光催化活性之间没有成比例的关系.     

掺铁TiO2纳米微粒的制备及光催化活性

采用溶胶-凝胶法制备了不同掺铁量及不同pH值下的一系列TiO2光催化剂，并以高压汞灯为光源，罗丹明B为目标降解物，对其光催化活性进行了研究．实验表明，Fe^3 ．TiO2比纯TiO2具有更好的催化活性，且Fe^3 的最佳掺入量为0．05％，最佳制备的pH值为5。     

机械化学法N掺杂纳米TiO2的制备与表征

采用机械化学法合成了N掺杂纳米TiO_2粉末,对所获得的N掺杂TiO_2粉末进行了分析与表征．实验结果表明,采用六次甲基四胺(HMT)为N源,将原料TiO_2和HMT混合物经过高能球磨处理后,合成的N掺杂TiO_2主要为锐钛矿和板钛矿的混晶相,与原料相比具有小的晶粒度和大的比表面积,对波长大于400nm的可见光具有良好的吸收性能,其吸收边红移至530nm．     

二氧化钛负载型光催化剂的制备及光还原二氧化碳的研究

利用ＴｉＯ２负载钯、钌等作为二氧化碳光还原催化剂Ｐｄ／ＴｉＯ２、ＲｕＯ２／ＴｉＯ２和Ｐｄ／ＲｕＯ２,并利用电子探针分析了其表面载钯量和载钌量,用ＸＰＳ分析了表面和钌的价态,利用这些催化剂进行ＣＯ２光还原的结果表明：催化剂的制备方法对催化效果有较大影响;催化效率与催化剂表面的Ｐｄ或Ｒｕ＾４＋含量密切相关,即Ｐｄ或Ｒｕ＾４＋的含量越高,催化效果越好;另外,ＴｉＯ２表面同时修饰钯和钌后,催化效率比单独修     

Preparation and characterization of in-site regenerated TiO_2-ACFs photocatalyst

In-site regenerated titanium dioxide-activated carbon fibers (TiO2-ACFs) photocatalyst was prepared by the sol-gel method. De-tailed surface and structural characterization of the TiO2-ACFs photocatalyst was carried out. The photoactivity of TiO2-ACFs under ultra-violet irradiation was compared with original ACFs and pure TiO2 by the degradation of methylene blue aqueous solution. The degradation efficiency by the TiO2 (5wt%)-ACFs sample is much higher than that by TiO2 and ACFs. The results show that the p...     

TiO2／SiO2核壳结构微粒的合成及超疏水防紫外线功能织物的制备

以正硅酸乙酯为前驱体,采用溶胶-凝胶法在纳米TiO2表面包覆SiO2壳层,制备TiO2／SiO2核壳结构复合微粒,并将其负载在涤纶织物上,然后对织物进行疏水化处理,得到具有超疏水和防紫外线双重功能的织物．采用透射电子显微镜对复合微粒进行了表征;采用扫描电子显微镜对涤纶及处理后的涤纶织物的表面形貌进行了观察;采用视频光学接触角测量仪对涤纶织物表面的润湿性能进行测试;对织物超疏水性能的稳定性以及织物的紫外线防护性能进行了研究．结果表明：TiO2／SiO2复合微粒在纤维表面的负载不仅极大地提高了纤维表面的粗糙性,有利于超疏水表面的形成,并且由于TiO2的引入使织物获得了良好的紫外线防护性能;SiO2壳层对TiO2的包覆降低了TiO2的光催化作用,从而有效地提高了超疏水表面的紫外光照射稳定性．     

TiO2／累托石吸附和光催化降解处理造纸废水

采用TiOSO4水解一沉淀反应法，制备高活性TiO2／累托石．利用SEM和XPS等方法对其进行：表征．通过对造纸废水的光催化降解性能研究，确定了废水通过反应器的流量、废水pH值和循环处理次数对光催化性能的影响；实验表明：流量为12mL／min，pH=5．0时，COD的去除率可达88．76％．     

Pt/TiO2纳米管的制备及其电化学性能研究

采用微波加热多元醇还原的方法制备了贵金属Pt负载的TiO2纳米管复合材料,并对其形貌和结构进行了表征。结果表明,试验中所制备的TiO2纳米管直径约10nm左右,长度达到几百纳米甚至微米级。微波法负载的Pt粒子粒径分布均匀,尺寸约在4.5nm左右。电化学结果表明该复合纳米材料对甲醇具有一定的催化氧化作用。     

C／T iO 2复合材料的制备及光催化性能的研究

采用溶胶-凝胶法制得了C/TiO2复合光催化剂,并采用X射线衍射（XRD）﹑扫描电子显微镜（ SEM ）﹑紫外光谱等方法对复合材料进行了表征。以1-萘胺-4-偶氮对苯磺酸为模型化合物评价了C/TiO2复合材料的光催化性能,考察了降解时间、初始浓度和催化剂投加量等因素对降解率的影响。研究表明,在1-萘胺-4-偶氮对苯磺酸初始浓度为2×10-5 mol/L,催化剂投加量为1．0 g/L时,光催化反应5 h后,1-萘胺-4-偶氮对苯磺酸的降解率达到85．41％。