负载型TiO_2/蛇纹石光催化降解4BS染料的研究

以蛇纹石为载体,利用TiOSO4为前驱体,采用水解-沉积法将TiO2超细粒子包覆在蛇纹石表面制得TiO2/蛇纹石负载型光催化剂。探讨了pH值、焙烧温度及光催化剂中TiO2与蛇纹石比例对偶氮直接耐酸大红4BS水溶液的光催化脱色降解的影响。结果表明,在pH为2～4,500℃条件下有明显地脱色效果。

纳米TiO_2光催化降解紫丁香基木素模型物

在光催化反应器中,以紫外灯作为光源,对紫丁香基木素的模型物紫丁香醇进行光催化降解实验,讨论了悬浮体系中纳米TiO2光催化降解紫丁香醇的反应特性。实验结果表明,在避光条件下反应60 min后,溶液中紫丁香醇在纳米TiO2催化剂表面可以达到吸附解吸平衡,纳米TiO2表面饱和吸附量为起始质量浓度的16.3%;根据降解吸光度曲线,当纳米TiO2用量0.4 mg/L、pH值7、连续曝气和搅拌条件下,经一定光强的紫外光照射12 h,初始质量浓度为40.5 mg/L的紫丁香醇溶液去除率达到52.08%,继续光照4 h,最终可以完全矿化;根据降解吸光度曲线和特征官能团显色实验初步推断:紫丁香醇结构中部分双甲氧基在光照条件下,与苯环发生了断裂,生成了具有单甲氧基结构的中间体——愈创木酚;并定量分析了降解过程中紫丁香醇和愈创木酚的质量浓度。

TiO_2光催化降解有机污染物的研究进展

介绍TiO2光催化降解有机物的基本原理和近年来在光催化降解方面的研究现状，如TiO2催化活性的改进及其方法，某些特种有机物的降解效果，特别是二恶英类（CDDS）的光降解探索性研究。

载银纳米TiO_2光催化降解水中有机污物

以TiOSO4和TiOCl2 为原料 ,合成出锐钛相和金红石相的相对含量分别约为 85 %和 1 5 %的纳米TiO2 光降解催化剂。在纳米TiO2 表面担载质量分数为 0 5 %的银后 ,不但能较好地提高催化活性和使用寿命 ,而且表现出特有的絮凝作用 ,使催化剂易于分离 ,达到多次循环使用的目的。对光催化降解活性黑模拟污水 ,以及蒽醌类染料、糖厂等实际污水发现 ,这种纳米TiO2 具有活性高、寿命较长的特点 ,且能多次循环使用 ,降低了处理污水的成本。

废水中硝基苯的光催化降解实验研究

采用锐钛型TiO2光催化剂,对废水中的硝基苯进行光催化降解,探究了催化剂投放量、硝基苯浓度、溶液的pH值及反应时间等因素对降解效率的影响,实验结果表明,以锐钛型TiO2为催化剂的光催化技术对硝基苯有理想的处理效果;催化剂投放量控制在3 g/L;废水的初始pH对硝基苯的处理效果影响不大;紫外光照射6.5 h,降解效率基本稳定在78%。

Facile synthesis of C-decorated Fe,N co-doped TiO_2 with enhanced visible-light photocatalytic activity by a novel co-precursor method

Lattice‐doping and surface decoration are prospective routes to improve the visible‐light photocatalytic ability of TiO2,but the two techniques are difficult to combine into one preparation process because they are usually conducted under different conditions,which limits the efficiency of TiO2 modification.In this study,TiO2 was successfully modified by simultaneous lattice‐doping and surface decoration,and the visible‐light photocatalytic capacity was largely improved.Upon comparing the method reported here with previous ones,the most significant difference is that Fe(II)‐phenanthroline was first used as the co‐precursor of the introduced elements of C,N,and Fe.These three elements were simultaneously introduced to TiO2 at high levels by this co‐precursor method.The as‐synthesized photocatalysts were systemically investigated and analyzed by several characterization methods such as XRD,FT‐IR,XPS,Raman spectroscopy,EPR,UV‐Vis DRS,photoluminescence spectra,photocurrent,electrochemical impedance spectra,TEM,and HRTEM.The photocatalytic degradation of 4‐NP under visible‐light irradiation was used to evaluate the photocatalytic activity of the photocatalysts.Based on the experimental data,a probable mechanism for the photocatalytic degradation by the photocatalysts is proposed.This is a novel method of using one source to simultaneously introduce metal and non‐metal elements to TiO2 at high levels,which may provide a new way to prepare highly effective TiO2 photocatalysts.

Studies on characteristics of nanostructure of N-TiO_2 thin films and photo-bactericidal action

Pseudomonas aeruginosa strain （AS 1.50） and Bacillus subtilis strain （AS 1.439） from Ming lake were decomposed by photocatalytic nanostructure N-TiO2 thin films in a photo-reactor under UV irradiation. The different thickness nanostructure N-TiO2 thin films coated on mesh grid were prepared by sol-gel method and immobilized at 500 ℃ （films A） or 350 ℃ （films B） for 1 h in a muffle furnace. The results showed that N-TiO2 thin film B （8.18 nm thickness, 2.760 nm height and 25.15 nm diameter） has more uniform granular nanostructure and thinner flat texture than N-TiO2 thin film A （12.17 nm thickness, 3.578 nm height and 27.50 nm diameter）. The bactericidal action of N-TiO2 thin film A and film B for Pseudomonas aeruginosa strain （AS 1.50） and Bacillus subtilis varniger strain （AS1.439） were investigated in this work. More than 95% of photocatalytic bactericidal efficiency for Pseudomonas aeruginosa strain （AS 1.50） and 75% for Bacillus subtilis strain （AS 1.439） were achieved by using N-TiO2 thin films-B for 70-80 rain of irradiation during the photo-bactericidal experimental process. The results indicated that the photo-induced bactericidal efficiency of N-TiO2 thin films probably depended on the characteristics of the films.

Enhanced visible photocatalytic activity of TiO_2 hollow boxes modified by methionine for RhB degradation and NO oxidation

Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited by ultraviolet light.In this paper,visible‐light‐responsive N and S co‐doped TiO2‐HNBs were prepared by calcining the mixture of cubic TiOF2 and methionine(C5H11NO2S),a N‐and S‐containing biomacromolecule.The effect of calcination temperature on the structure and performance of the TiO2‐HNBs was systematically studied.It was found that methionine can prevent TiOF2‐to‐anatase TiO2 phase transformation.Both N and S elements are doped into the lattice of TiO2‐HNBs when the mixture of TiOF2 and methionine undergoes calcination at 400°C,which is responsible for the visible‐light response.When compared with that of pure 400°C‐calcined TiO2‐HNBs(T400),the photoreactivity of 400°C‐calcined methionine‐modified TiO2‐HNBs(TM400)improves 1.53 times in photocatalytic degradation of rhodamine‐B dye under visible irradiation(?>420 nm).The enhanced visible photoreactivity of methionine‐modified TiO2‐HNBs is also confirmed by photocatalytic oxidation of NO.The successful doping of N and S elements into the lattice of TiO2‐HNBs,resulting in the improved light‐harvesting ability and efficient separation of photo‐generated electron‐hole pairs,is responsible for the enhanced visible photocatalytic activity of methionine‐modified TiO2‐HNBs.The photoreactivity of methionine modified TiO2‐HNBs remains nearly unchanged even after being recycled five times,indicating its promising use in practical applications.

Effects of Magnetic Field on Photodegradation of Methylene Blue over ZnO and TiO2 Powders using UV-LED as a Light Source

The magnetic field effects （MFEs） are studied on photocatalytic degradation of methylene blue （MB） solution using ZnO and TiO2 particles. The UV-VIS-NIR spectrometer is used to monitor the MB concentrations, and the dependence of the reaction rate on the initial dye concentration and settling duration is studied under UV light irradiation. It is found that the MFEs exist on the heterogeneous reaction systems for both ZnO and TiO2 powders and that the extraordinary phenomenon is reproducible. For ZnO powder, the results are in good agreement with the second-order reaction kinetics following the Langmuir-Hinshelwood （L-H） model, while the reaction for TiO2 follows first-order kinetics. It enhances the photodegradation for ZnO, while it reduces or enhances the reaction for TiO2 depending on the initial dye concentrations. The MFEs become small or negligible when the same photodecomposition experiment is carried out after settling the MB solution for more than three hours for both ZnO and TiO2. It is suggested that the key factors of MFEs on photocatalytic degradation is the condition of the MB solution as well as the characteristics of photocatalysts. The alteration of the MFEs ascribed to the solution condition caused by variation of the settling time.

Enhanced performance of g-C_3N_4/TiO_2 photocatalysts for degradation of organic pollutants under visible light

Photocatalytic degradation is one of the most promising remediation technologies in terms of advanced oxidation processes(AOPs) for water treatment. In this study, novel graphitic carbon nitride/titanium dioxide(gC3N4/Ti O2) composites were synthesized by a facile sonication method. The physicochemical properties of the photocatalyst with different mass ratios of g-C3N4 to Ti O2 were investigated by X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscopy(TEM), N2 sorption, Fourier transform infrared spectroscopy(FT-IR), X-ray photoelectron spectroscopy(XPS), and UV–vis DRS. The photocatalytic performances were evaluated by degradation of methylene blue. It was found that g-C3N4/Ti O2 with a mass ratio of 1.5:1 exhibited the best degradation performance. Under UV, the degradation rate of g-C3N4/Ti O2 was 6.92 and 2.65 times higher than g-C3N4 and Ti O2, respectively. While under visible light, the enhancement factors became 9.27(to g-C3N4) and 7.03(to Ti O2). The improved photocatalytic activity was ascribed to the interfacial charge transfer between g-C3N4 and Ti O2. This work suggests that hybridization can produce promising solar materials for environmental remediation.

TiO_2/Polyester Non-woven Fabrics as a Kind of Photocatalyst for the Degradation of Formaldehyde Gas

The feasibility of photocatalytic degradation of the formaldehyde gas by titanium dioxide （TiO2）/polyester non-woven fabrics was studied. Tbe effects of parameters such as tbe concentration of TiO2 solution, pH value, and drying temperature on the photocatalytic degradation of the formaldehyde gas were also studied. The results showed that the photodegradation efficiency of the formaldehyde gas increased rapidly with the increasing of the concentration of TiO2 solution up to 15g/L, but when the concentration was in excess of 15g/L, the photodegradation efficiency decreased gradually and fluctuated due to light obstruction and disperse state of TiO2. Adjusting the pH value in the solution, the efficiency of photocatalytic degradation of the formaldehyde gas could be improved. The mechanisms of the reaction and the role of the additives were also investigated. After 42hours, TiO2/ polyester non-woven fabric showed no significant loss of the photocatalytic activity.

Photocatalytic Activity of TiO_2 Coating on Natural Feather Zeolite in Degradation of Orthomonochlorphenol

Ti02 coatings on natural feather zeolite are respectively prepared by a collosol （Sol-gel） method and two powder coating methods with deionizod water or dehydrated ethanol as a dispersant. During degradation of orthomono- chlorphenol solutions by ultraviolet, the strong adsorption capability of the zeolite results in increased concentration of substrate on its surface. The Ti（h film coated on feather zeolite further enhances the photocatalytic activity. The TiO~ film on the zeolite prepared by the Sol-gel method is found more effective as a catalyst than that by two powder coating methods.

Treating dye wastewater by TiO_2 coated on coal cinder

We investigated the photocatalytic degradation of dye wastewater by using titanium dioxide （TiO2） coated on a coal cinder. The coal cinder was used as the carrier, with a thin film of TiO2 coated on it by using the sol-gel method. Using the Congo red as the model pollutant for dye wastewater, we studied the decolorization efficiency, and effects of TiO2 film thickness and roasting temperature on the efficiency. We also evaluated the recycling and regeneration of the immobilized TiO2 （TiO2/cinder）. Results show that the decolorization rate of Congo red solution was more than 98% after 2.h treatment when we used TiO2/cinder calcined at 500 ℃ for 2 h and coated four times as the photocatalyst. At the same time, the TiO2/cinder remained high catalytic activity after being reused and regenerated for many times.