掺锌纳米TiO_2光催化性能研究

以钛酸四丁酯、硝酸锌为主要原料,采用溶胶-凝胶法制备掺锌纳米TiO2微粒.以罗丹明B为目标降解物,考察了掺锌纳米TiO2粉体的光催化活性.结果表明:300℃焙烧4.5 h时,得到的催化剂活性最高.在紫外光照射下,催化效果明显优于太阳光照射(在紫外光下,pH值为2时,用1 g/L掺锌2.7%纳米TiO2光照70 min,罗丹明B的降解率接近100%;在太阳光下,pH值为10时,用4 g/L掺锌3.0%纳米TiO2光照120 min,罗丹明B的降解率达93%).     

Pr-TiO2纳米复合催化剂的制备及其光催化降解性能

采用溶胶-凝胶法制备了Pr-TiO2纳米复合催化剂,并用DRS、FT-IR、XRD和SEM等对样品形态和结构进行了表征,以罗丹明B(Rh B)印染废水作为探针反应,分别在紫外光和可见光照射下评价其光催化性能.与TiO2纳米催化剂的光催化活性进行对比,Pr-TiO2纳米复合催化剂对罗丹明B溶液(5 mg/L)具有较高的光催化降解性能,可见光下的降解率达到97%.     

Ce-SiO2-TiO2三元复合催化剂的制备及其光催化降解性能

采用溶胶-凝胶法制备了Ce-SiO2-TiO2三元复合纳米催化剂,用TG-DTA、FT-IR、XRD和UV-Vis等对样品的结构进行了表征,并以罗丹明B(RhB)作为探针反应,分别在紫外光和可见光照下评价了其光催化性能.与TiO2一元纳米催化剂和Ce-TiO2、SiO2-TiO2二元纳米催化剂进行对比,Ce-SiO2-TiO2三元复合纳米催化剂对罗丹明B溶液(5 mg/L)表现出更高的光催化降解性能,可见光下的降解率达到98.5%.     

掺镧TiO_2光催化降解罗丹明B的研究

采用溶胶-凝胶法制备了掺镧TiO2微粒.以罗丹明B为目标降解物,分别在太阳光和紫外灯下照射,考察了掺镧TiO2光催化活性.结果表明:在紫外光下,pH值为6时,用4 g/L掺镧0.25%TiO2降解罗丹明B光催化活性最佳;在太阳光下,pH值为6时,用5 g/L掺镧0.075%TiO2降解罗丹明B光催化活性最佳;加入H2O2都能提高光催化效果,在太阳光下,由于TiO2和H2O2的协同作用,催化降解率能达到90%以上.     

Zn2+-SiO2-TiO2三元复合催化剂的制备及其光催化降解性能

采用溶胶-凝胶法制备了Zn2+-SiO2-TiO2三元复合纳米催化剂,并用DRS、FT-IR、XRD和SEM等对样品的形态和结构进行了表征,并以罗丹明B和刚果红染料的印染废水做探针反应,分别在紫外光和可见光照射下评价了其光催化性能.与TiO2一元纳米催化剂和Zn2+-TiO2、SiO2-TiO2二元纳米催化剂进行对比,Zn2+-SiO2-TiO2三元复合纳米催化剂对罗丹明B溶液(5 mg/L)和刚果红溶液(10 mg/L)都表现出较高的光催化降解性能,可见光下的降解率分别达到90%和83%.     

可见光下TiO_2/α-ZrP复合材料光催化降解罗丹明B

以TiO2/α-ZrP复合材料为可见光光催化剂,采用氙灯模拟可见光,研究了TiO2/α-ZrP复合材料对有机染料罗丹明B的光催化降解情况。试验探究了TiO2的掺杂量、反应时间、染料浓度、光催化剂用量、染液pH值等对光催化降解罗丹明B的影响。结果表明,当TiO2的掺杂量为17%时,TiO2/α-ZrP复合材料的光催化活性最高。浓度为6×10-5mol/L的罗丹明B溶液的最佳降解条件为:染液初始pH值为4,TiO2/α-ZrP复合光催化剂质量浓度为3.6 g/L。     

La^3＋／TiO2／AC原位光电催化性能的研究

为了减少印染水污染、节约水资源,通过自行研制的“多层间隔固定床”非均相三维电极光电催化反应器。对工厂中常用的Levafix Red活性染料进行脱色研究：并对该光电反应器进行了La^3＋／TiO2负载活性炭三维粒子电极和活性染料降解率的表征。研究了光催化、电催化氧化及光电催化体系对活性染料的降解率曲线,结果表明,在相同条件下,“光电协同催化体系的降解速率常数”大于“电催化与光催化体系的降解速率常数之和”;自行研制的新型光电催化反应器具有良好的协同效应。在该光电催化反应器中。间隔式结构和压缩空气可有效地增强传质效应和光激发的TiO2粒子电极之间的碰撞几率,从而使得外电场能有效地捕获光生电子。     

低温制备纳米TiO2溶胶整理棉织物对染料的降解

 在室温条件下使钛酸丁酯水解制备纳米TiO2溶胶,然后利用后整理技术将其负载于棉纤维表面得到纳米TiO2整理棉织物。在对纳米TiO2溶胶及其整理棉织物表征的基础上,将纳米TiO2整理棉织物作为光催化剂应用于有机染料罗丹明B的降解反应中,重点考察了水与钛酸丁酯的物质的量比、陈化时间以及纳米TiO2整理棉织物增重率对脱色率的影响,并研究了纳米TiO2整理棉织物的重复利用性和罗丹明B的降解反应动力学。结果表明,在纳米TiO2溶胶的制备中,水与钛酸丁酯物质的量比的增加能形成粒径小而均匀的溶胶。通过浸烘整理工艺能使纳米TiO2溶胶在棉纤维表面形成锐钛型纳米TiO2结晶薄膜。当纳米TiO2整理棉织物作为光催化剂时,罗丹明B的脱色率随增重率的增加而提高,并且水与钛酸丁酯物质的量比的增加和陈化时间的延长都能够明显改善其光催化活性。纳米TiO2整理棉织物作为光催化剂可以重复使用,并且罗丹明B在纳米TiO2整理棉织物存在下的光催化降解反应符合假一级动力学反应模型。     

二硫化钼/聚丙烯腈复合纳米纤维膜的制备及其光催化性能

采用水热合成法制备了无机半导体光催化剂二硫化钼(MoS_2),利用静电纺丝技术,将MoS_2粉末添加到不同质量分数的聚丙烯腈(PAN)溶液中进行共混纺丝,制备MoS_2/PAN复合纳米纤维膜,并用于罗丹明B溶液的催化降解。借助扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线衍射(XRD)等对纳米纤维膜的形貌和性能进行表征。结果表明:MoS_2/9%PAN复合纳米纤维膜中的纳米纤维形貌较好,直径较均匀,MoS_2在纳米纤维上的分布也较为均匀;使用其对30 mL的10 mg/L罗丹明B溶液进行光催化降解,光催化效果好,降解率达89.8%,重复使用3次后,降解率仅下降了2.3%,表现出良好的循环使用性。     

Ni-Zr共掺TiO_2纳米粉体的光催化性能研究

通过溶胶-凝胶法制备掺杂Ni-Zr共掺纳米TiO_2,采用XRD、TEM和DRS等方法对光催化剂的晶向结构、显微形貌和光响应特性进行表征,并以罗丹明B为目标降解物,测试其光催化性能。结果表明Zr掺杂能够降低TiO_2光催化剂的粒径,改善其光响应特性。Ni~(2+)和Zr~(4+)共掺杂可以通过协同作用提高样品的光催化活性。Ni-Zr共掺TiO_2比纯TiO_2具有更好的光催化效果,2%Zr和Ni共掺杂TiO_2光照60min后对罗丹明B的降解率达到92%,比纯TiO_2提高30%以上。     

Synergetic degradation of rhodamine B at a porous ZnWO4 film electrode by combined electro-oxidation and photocatalysis

Synergetic degradation of rhodamine B (RhB) was investigated by combining electro-oxidation and photocatalysis using porous ZnWO4 film at various bias potentials. The applied bias potential below 0.8 V enhanced the photocatalytic degradation of RhB by promoting the separation and transfer of photogenerated holes and electrons. At the potential between 0.8 and 1.0 V, the degradation of RhB was further enhanced, which is induced by direct electro-oxidation and photocatalysis. At the potential greater than 1.3 V, indirect electro-oxidation of RhB occurred with the largest synergetic effect. The synergetic effect can also increase the mineralization degree of the RhB. On the basis of the X-ray photoelectron spectra (XPS) analysis of the surface of the electrode after electrochemical reaction, the electropolymerization occurred which blocked the electrode and slowed the electro-oxidation of RhB. Active species generated via the photocatalytic process can activate the passivated electrode and promote the electro-oxidation of RhB. The O2 electrochemically generated at the anode promoted the photocatalysis by capturing the photogenerated electrons and may induce the formation of H2O2. Thus, more active species could be formed through new reactive routines in the photoelectrocatalytic (PEC) process. RhB degradation was mainlythrough decomposition of the conjugated chromophore structure with slight occurrence of de-ethylation. The stability of the electrode in the PEC process was confirmed based on the XPS and Raman analysis.     

不同纳米TiO2负载棉织物在染料降解反应中的比较研究

将低温制备的两种纳米TiO2水溶胶和两种商品化纳米TiO2粉体（5 nm和30 nm）通过浸轧工艺负载于棉织物表面形成纳米TiO2负载棉织物。在经过XRD和SEM表征后,四种纳米TiO2负载棉织物被用于纺织染料酸性红88的降解反应中,考察和比较了它们的光催化降解性能。结果表明,四种纳米TiO2都属于锐钛型,但是水溶胶中的纳米TiO2结晶并不完善。两种纳米TiO2水溶胶和5 nm纳米TiO2粉体在纤维表面所形成薄膜具有相似的形貌,但是与30 nm纳米TiO2粉体所形成薄膜形貌明显不同。两种纳米TiO2水溶胶和5 nm纳米TiO2粉体负载棉织物在酸性和中性介质中的催化降解性能高于30 nm纳米TiO2粉体负载棉织物,但是在碱性介质中两种纳米TiO2粉体负载棉织物的催化降解性能却高于两种纳米TiO2水溶胶负载棉织物。在可见光辐射条件下30 nm纳米TiO2粉体负载棉织物 的催化降解性能显著低于其它三种纳米TiO2负载棉织物,而氯化钠或十二烷基苯磺酸钠存在时纳米TiO2粉体负载棉织物却显示出比纳米TiO2水溶胶负载棉织物更好的催化降解性能。     

N-TiO_2/ACF的制备及光催化降解真丝绸染色废水研究

利用扫描电镜、X射线衍射、紫外-可见漫反射等技术对采用溶胶-凝胶法制备的氮掺杂纳米TiO_2负载活性炭纤维(N-TiO_2/ACF)光催化材料进行了表征分析。以真丝绸染色废水为目标降解物,研究了光催化材料的光催化性能。研究表明:N-TiO_2/ACF光催化材料表面的N-TiO_2呈锐钛矿相,粒径约为15.3 nm,其光谱响应范围由紫外光区拓展至可见光区,吸收边带达603 nm;金卤灯照射下反应180 min,0.77 g N-TiO_2/ACF对200 m L真丝绸染色废水降解率达97.2%,2.31 g的N-TiO_2/ACF对200 mL真丝绸染色废水COD去除率达80.6%;N-TiO_2/ACF具有良好的重复使用性能。     

Solid-state, planar photoelectrocatalytic devices using a nanosized TiO2 layer

Solid-state planar photoelectrocatalytic devices using a nanosized Ti02 layer have been fabricated and used in the photodegradation of gaseous formaldehyde (HCHO). It is discovered for the first time that in the photocatalytic degradation of HCHO over TiO2 film, besides a well-known process of exciton dissociation expressed as TiO2* --> e(-) + h+ (process A), there exists an HCHO-involved process of exciton dissociation expressed as TiO2 + HCHO* --> TiO2(-) + HCHO+ (process B); these two processes have comparable contributions to the electron photogeneration. A biased photocatalytic device is unable to photodegrade HCHO under the nitrogen condition, but under the air condition, a positive synergic effect of bias on the photodegradation of HCHO over the planar photoelectrocatalytic device has been observed, mainly attributed to it that the horizontal electric field can displace electrons generated via process B away from their counterparts, effectively suppressing hole-electron recombination on TiO2 surface and thereby leading to the enhanced formation of O2- species. The current research points out that the planar photoelectrocatalytic device can provide the in-depth investigations on the mechanisms of the photocatalytic degradation over nanosized semiconductor oxide films, and also have potential application in decomposing and mineralizing organic gas-phase pollutants.     

Preparation of titania nanotubes and their environmental applications as electrode

Titanium oxide nanotubes were successfully grown from a titanium plate by direct anodic oxidation with 0.2 wt % hydrofluoric acid being the supporting electrolyte. These nanotubes are of uniform size and are well-aligned into high-density arrays. They look like honeywell with the structure similar to that of porous alumina obtained by the same technique. TiO2 anatase phase was identified by X-ray diffraction. Significant blue-shift in the spectrum of UV- vis absorption was observed. The mechanism of the novel, simple, and direct growth of the nanotubes was postulated. To investigate their potentials in environmental applications, degradation of pentachlorophenol (PCP) in aqueous solution was carried out using photoelectrocatalytic (PEC) processes, comparing with electrochemical process (EP) and photocatalytic (PC). A significant photoelectrochemical synergetic effect was observed. The kinetic constant of PEC degradation of PCP using TiO2 nanotubes electrode was 86.5% higher than that using TiO2 film electrode. In degrading PCP, 70% of TOC was removed using the TiO2 nanotubes electrode against 50% removed using TiO2 film electrode formed by sol-gel method in 4 h under similar conditions.     

Degradation of dye pollutants by immobilized polyoxometalate with H2O2 under visible-light irradiation

A Keggin polyoxometalate (POM, i.e., PW12O40(3-)) and its lacunary derivative are immobilized on an anionic exchange resin through electrostatic interaction at pH 4.6 in an aqueous dispersion. The resin-supported POM thus obtained catalyzes the efficient degradation of cationic dye pollutants in the presence of H2O2 under visible-light irradiation. To evaluate the photocatalytic system, degradation of a rhodamine B (RB) dye was investigated in detail using UV-visible spectroscopy, high performance liquid chromatography, and gas chromatography/mass spectrometry techniques to identify the intermediates and final products. Fluorescence lifetime measurements revealed the electron transfer from the visible-light-excited RB molecules to the POMs. Electron paramagnetic resonance measurements, investigation of the effects of *OH and *OOH scavengers on the photoreaction kinetics, and IR analysis indicated that de-ethylation of RB was due to *OOH radicals, but the decomposition of the conjugated xanthene structure was caused by the peroxo species formed by interaction of H2O2 with the lacunary POM loaded on the resin. A total organic carbon removal of ca. 22% was achieved, and the recycle experiment suggested excellent stability and reusability of the heterogeneous catalyst. On the basis of the experimental results, a photocatalytic mechanism is discussed.     

TiO_2薄膜的制备及对罗丹明B光催化分解过程的影响

采用sol gel法在玻璃表面制备了TiO2 薄膜 .X射线衍射表明 ,该薄膜的结构为锐钛矿型 .通过考察罗丹明B的光催化分解过程 ,发现TiO2 薄膜对罗丹明B的光催化分解有很好的活性 ,可以完全分离罗丹明B .通过考察罗丹明B在TiO2 薄膜上的吸附性 ,发现当薄膜吸附罗丹明B达到一定量时 ,脱乙基反应将与降解反应同时发生     

多酸基金属-有机框架负载棉织物的制备及其光催化性能

为制备具有光催化性能的棉织物,通过引入金属有机框架材料,将尺寸适合的多金属氧酸盐装入其中,从而实现多金属氧酸盐在棉织物上的原位生长。研究了金属离子反应时间、多金属氧酸盐用量、有机配体和多金属氧酸盐的反应时间对制备的负载有多酸基金属-有机框架(POMOF)棉织物光催化性能的影响,借助扫描电子显微镜、傅里叶红外光谱仪等对POMOF负载棉织物的形貌与结构进行表征。结果表明:对棉织物进行羧基化改性,可在其表面形成多的活性位点;当改性棉织物在硝酸铜溶液中反应12 h,均苯三甲酸与多钨酸盐的量比为 1∶14, 有机配体和多酸的反应时间为10 h时,POMOF负载棉织物在135 min内对罗丹明B溶液(10 mg/L)的降解率达92.23%;该POMOF负载棉织物具有良好的光催化性能,在印染废水降解方面有较大潜力。     

可见光激发降解甲基橙的光催化漂浮球的制备

为推广多相光催化技术在特殊废水深度治理中的应用,采用耦合吸附相反应技术和热还原处理制备了高活性的可见光响应的贵金属沉积光催化组分。将该光催化组分负载于多孔聚氨酯海绵颗粒表面后,填充至聚丙烯空心球中构建漂浮式光催化球,并用于高含盐废水中甲基橙的光降解。结果表明:通过吸附相反应技术可在TiO₂光催化剂表面沉积小粒径且与TiO₂表面紧密结合的贵金属纳米粒子,从而在光催化组分中引入费米能级并形成表面等离子体共振效应,增强光催化组分在可见光激发下对高含盐废水中甲基橙的降解性能;由于贵金属沉积光催化组分的高效降解性能,其负载后构建的漂浮式光催化球也能稳定高效地降解高含盐废水中的甲基橙。