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1.
In the present study, poly(vinyl chloride)/titanium dioxide (PVC/TiO 2) nanocomposite films containing different amounts of synthesized TiO 2 nanoparticles and commercial rutile powder were irradiated for 5112 hr, under exposure of artificial ultraviolet and visible lights in three different intensities. The rate of degradation was determined by using weight loss data and was found to follow a pseudo‐first order kinetic model. To determine the overall rate constant of degradation, k, a possible mechanism of the photodegradation was considered. The rate equation demonstrated k as a function of TiO 2 concentration and irradiation intensity at each wavelength. The overall rate constant of PVC/TiO 2 samples were calculated to be varied in the range of 6–16 × 10 ?7 hr ?1, at all investigated conditions. The kinetic study represented that by adding synthesized TiO 2 nanoparticles, even at low content, and with increasing their concentration, the photodegradation rate of nanocomposites decreased considerably compared with the composite samples. Likewise, by adding nanoparticles, a significant increase in the nanocomposites lifetime was achieved. The effect of irradiation intensity was investigated according to the reciprocity law experiments, and it was found that photodegradation occurred in two regimes with respect to irradiation intensity. The calculated overall rate constants were validated by the experimental data. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
2.
Photocatalytic multilayer nanocomposite films composed of anatase TiO 2 nanoparticles and lignosulfonates (LS) were fabricated on quartz slides by the layer‐by‐layer (LBL) self‐assembly technique. X‐ray photoelectron spectroscopy (XPS), UV‐vis spectroscopy and atomic force microscopy (AFM) were used to characterize the TiO 2/LS multilayer nanocomposite films. Moreover, the photocatalytic properties (decomposition of methyl orange and bacteria) of multilayer nanocomposite films were investigated. XPS results indicated that the intensities of titanium and sulfur peaks increased with the LBL deposition process. A linear increase in absorbance at 280 nm was found by UV‐Vis spectroscopy, suggesting that stepwise multilayer growth occurs on the substrate and this deposition process is highly reproducible. AFM images showed that quartz slide was completely covered by TiO 2 nanoparticles when a 10‐bilayer multilayer film was formed. The decomposition efficiency of methyl orange by TiO 2/LS multilayer films under the same UV irradiation time increased linearly with the number of TiO 2 layers, and the results of decomposition of bacteria under UV irradiation showed that TiO 2/LS multilayer nanocomposite films exhibited excellent decomposition activity of bacteria ( Escherichia coil). 相似文献
3.
The gas-phase photocatalytic oxidation of aniline on a new kind of porous nano-TiO 2 composite films is investigated. The composite film was prepared on glass fiber with the water glass as binders and dilute
H 2SO 4 solution as solidifying reagent. The surface characters were observed by scanning electron microscope. The photocatalytic
degradation of aniline on the composite films was carried out in a TiO 2/UV system. Some important factors affecting the photodegradation, such as the concentration of TiO 2, the initial concentration of aniline, and the existing water vapor, are also studied. The product of photocatalytic oxidation
was detected by Fourier transform-Infrared. The partial intermediate products were absorbed on TiO 2 surface, which resulted in catalyst deactivation. But when it was irradiated under UV illumination or solar irradiation for
some time, the catalyst could be reused without loss of catalytic activity.
Translated from the Journal of Wuhan University (Natural Science Edition), 2005, 51(2) (in Chinese) 相似文献
4.
A magnetized nano‐photocatalyst based on TiO 2/magnetic graphene was developed for efficient photodegradation of crystal violet (CV). Scanning electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy and elemental mapping were used to characterize the prepared magnetic nano‐photocatalyst. The photocatalytic activity of the synthesized magnetic nano‐photocatalyst was evaluated using the decomposition of CV as a model organic pollutant under UV light irradiation. The obtained results showed that TiO 2/magnetic graphene exhibited much higher photocatalytic performance than bare TiO 2. Incorporation of graphene enhanced the activity of the prepared magnetic nano‐photocatalyst. TiO 2/magnetic graphene can be easily separated from an aqueous solution by applying an external magnetic field. Effects of pH, magnetized nano‐photocatalyst dosage, UV light irradiation time, H 2O 2 amount and initial concentration of dye on the photodegradation efficiency were evaluated and optimized. Efficient photodegradation (>98%) of the selected dye under optimized conditions using the synthesized nano‐photocatalyst under UV light irradiation was achieved in 25 min. The prepared magnetic nano‐photocatalyst can be used in a wide pH range (4–10) for degradation of CV. The effects of scavengers, namely methanol (OH ? scavenger), p‐benzoquinone (O 2?? scavenger) and disodium ethylenediaminetetraacetate (hole scavenger), on CV photodegradation were investigated. 相似文献
5.
Commercial TiO 2 nanoparticles were superficially modified through polymeric resins obtained from polymerization of citrate complexes of Y 3+ and Al 3+ with ethylenglycol. The materials were treated at 450 °C for 4 h to obtain modified nanoparticles, which were characterized
by HR-TEM, Zeta potential and surface area through N 2 fisisorption. Rhodamine B photodegradation by visible light irradiation and in presence of those modified nanoparticles was
compared with the same process in presence of unmodified commercial TiO 2 nanoparticles. It was observed, by UV–visible spectroscopy, that the catalytic photoactivity in presence of modified nanoparticles
was smaller than that observed with commercial TiO 2 nanoparticles. However, the surface modifier played an important role in the photodegradation kinetic process, showing a
non-linear relation between modifier amount and photodegradation rate, presenting a maximum value at 0.8% (w/w). 相似文献
6.
This study is aimed to highlight the possibility of engineering the multifunctional textile nanocomposite material based on the polyester (PES) fabric modified with colloidal Ag and TiO 2 nanoparticles (NPs). The effects of concentration of NPs as well as the order of Ag and TiO 2 NPs loading on antimicrobial, UV protective, and photocatalytic properties of PES fabrics were examined. The antimicrobial activity of differently modified PES fabrics was tested against Gram‐negative bacterium Escherichia coli, Gram‐positive bacterium Staphylococcus aureus, and fungus Candida albicans. The concentration of Ag colloid and the order of Ag and TiO 2 NPs loading considerably affected the antimicrobial efficiency of PES fabrics. The fabrics provided maximum UV protection upon surface modification with Ag and TiO 2 NPs. Ag NPs enhanced Ag NPs enhanced the photodegradation activity of TiO 2 NPs and total photodegradation of methylene blue was achieved after 24 hr of UV illumination. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
7.
A series of nano-titania (TiO 2) photocatalytic materials with a hollow fiber structure were successfully prepared using tetra- n-butyl titanate (Ti(OC 4H 9) 4) as precursor and cotton fiber as the template. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and N 2 adsorption-desorption measurements were employed to characterize the morphology, crystal structure, and surface structure of the samples. The photocatalytic activities of the samples were studied by phenol photodegradation in water under UV irradiation. The effect of calcination temperature, photocatalyst dosage, initial concentration of phenol and irradiation time on the photodegradation of phenol was studied. Results showed that the TiO 2 fiber materials have hollow structures, indicating that these materials had a large specific surface area. The fiber structure material showed better photocatalytic properties for the degradation of phenol than pure TiO 2 under UV light, and the sample calcined at 500°C exhibited the highest phenol photodegradation efficiency. In addition, the possibility of cyclic usage of the photocatalyst was also confirmed, the photocatalytic activity of TiO 2 fiber remained ca. 90% of photocatalytic activity of the fresh sample after being used four times. Moreover, TiO 2 fiber was easily recovered by centrifugal separation from water. 相似文献
8.
This study discusses the possibility of using a corona discharge at atmospheric pressure and air RF plasma at low pressure
for the cotton fibre activation prior to deposition of colloidal TiO 2 nanoparticles in order to enhance antibacterial, UV protective and self-cleaning properties. X-ray photoelectron spectroscopy
(XPS) analysis confirmed the presence of TiO 2 nanoparticles on the surface of cotton fibres. XPS elemental mapping indicated that TiO 2 nanoparticles were more evenly distributed across the surface of untreated and corona pre-treated cotton fabrics in comparison
with RF plasma pre-treated fabric. Atomic absorption spectroscopy measurements revealed that the equivalent total content
of TiO 2 in the cotton fabrics pre-treated by corona and RF plasma was 31% higher than in the fabric that did not undergo any treatment
prior to loading of TiO 2 nanoparticles. In order to achieve maximum bacteria (Gram-negative bacteria Escherichia coli) reduction, untreated cotton fabric had to be loaded with colloidal TiO 2 nanoparticles twice, but only once following corona or RF plasma pre-treatment. Deposition of TiO 2 nanoparticles onto cotton fabrics provided maximum UV protective rating of 50+. Extraordinary photocatalytic activity of
TiO 2 nanoparticles deposited onto cotton fabrics was proved by self-cleaning of blueberry juice stains and photodegradation of
methylene blue in aqueous solution under UV illumination. 相似文献
9.
Gadolinium?Cboron codoped and mono-doped TiO 2 nanoparticles were prepared using a sol?Cgel method, and tested for photocatalytic activity by the UV light after a further calcination process. For comparison, a pure TiO 2 sample was also prepared and tested under the same conditions. The prepared catalysts were characterized by X-ray diffraction, scanning electron microscope, and UV?CVis spectra. The photocatalytic activity of the samples was evaluated through the photo-degradation of three different dyes under UV light. The experiments demonstrated that the gadolinium?Cboron codoped TiO 2 (Gd?CB?CTiO 2) sample calcined at 500?°C possessed the best photocatalytic activity, and the photodegradation rate of the Reactive Brilliant Red K2G aqueous solution could reach to 95.7% under UV irradiation for 80?min. The results showed that Gd?CB?CTiO 2 has smaller crystallite size and higher photocatalytic activity than that of mono-doped TiO 2 samples and undoped TiO 2. 相似文献
10.
Rhodamine B (RB) is a toxic dye used extensively in textile industry, which must be remediated before its drainage to environment. In the present study, supported gold nanoparticles on commercially available titania and zincite were successfully prepared and then their activity on the photodegradation of RB under UV A light irradiation was evaluated. The synthesized photocatalysts were characterized by ICP, BET, XRD, TEM and EDX. Kinetic results showed that Au/TiO 2 was a photocatalyst inferior to Au/ZnO. This observation could be attributed to the strong reflection of UV irradiation by gold nanoparticles over TiO 2 support. 相似文献
11.
A series of Bismuth-doped titanium oxide (Bi-doped TiO 2) thin films on glass substrates have been prepared by sol-gel dip coating process. The prepared catalysts were characterized by XRD and XPS. The photocatlytic activity of the thin film catalysts was evaluated through the photodegradation of aqueous methyl orange under UV illumination. The experiments demonstrated that the Bi-doped TiO 2 prepared was anatase phase. The doped bismuth was in the 3 + oxidation state. The presence of Bi significantly enhanced the photocatalytic activity of TiO 2 films. At calcination temperature of 500°C, with doping concentration of 2 wt %, Bi-doped TiO 2 thin film showed the highest photocatalyic activity. 相似文献
12.
In this study, TiO 2–ZnO nanostructured films prepared from different Ti/water mole ratios were deposited on glass plates by a sol–gel dip-coating method. The structural and surface properties, adherence, and photoactivity of synthesized TiO 2–ZnO coatings in methylene blue degradation were investigated. Among the as-prepared TiO 2–ZnO coatings from sols with different Ti/water mole ratios (1, 0.66, 0.5, and 0.4), the highest sol concentration (Ti/water mole ratio of 1) showed the highest methylene blue photodegradation of almost 80% after 400 min of UV irradiation. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray (EDX), and UV-vis diffuse reflectance spectra (DRS) confirmed that at high sol concentrations (Ti/water mole ratios of 1 and 0.66), a mixed phase of anatase and rutile is formed, whereas at a Ti/water mole ratio of 0.5, just pure rutile is formed. In detail, decreasing the sol concentration increases the cracks, degree of agglomeration, and the thickness of coatings. UV-vis DRS studies also confirm that decreasing the sol concentration in synthesized TiO 2–ZnO films leads to a shift in the absorption region of the coating to the UV region. Moreover, decreasing the sol concentration declines the coating adherence onto glass plates. TEM images of the TiO 2–ZnO coating synthesized from sol with a Ti/water mole ratio of 1 revealed the formation of ZnO nanorods around a spherical TiO 2, which indicates the presence of strong interaction between TiO 2 and ZnO nanoparticles. The TiO 2–ZnO coating synthesized from sol with a Ti/water mole ratio of 1 was then evaluated at different methylene blue concentrations, pH values, and number of coatings. After five consecutive runs, no significant decrease in the photodegradation efficiency was observed. Scanning electron microscopy (SEM) picture of used coating showed a smooth and stable layer without any detachment. Thermogravimetric analysis (TG) and sonication test confirmed thermal and mechanical stabilities of this coating as well. 相似文献
13.
Composites of visible-light-active bamboo charcoal powder (BCP)/TiO2 were fabricated by the straight calcination method by using TiCl4 as the source of titanium and natural bamboo as the carbon source. The dispersion of TiO2 nanoparticles was observed onto the surface of the BCP. The introduction of microstructure sizes of the bamboo powder played an important role in enhancing the optical properties of BCP/TiO2 composites. The composites of BCP/TiO2 showed the photocatalytic activities both under visible-light irradiation and UV irradiation. The methylene blue dye was used as the experimental check-up. The photodegradation reactions followed zero-order and pseudo-first-order kinetics. In the time duration of 100 min, about 58.31% and 95% of methylene blue were degraded by TiO2 and BCP/TiO2, respectively; 60 min more time was required by TiO2 to achieve 93% of degradation. This suggests that addition of BCP helps in the reduction in time and also shows high durability after up to four cycles having the degradation efficiencies of 95%, 94.1%, 92.7% and 86.6%, respectively. Hence, this research could overlay in the domain of green energy. 相似文献
14.
以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N 2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO 2皆为锐钛矿相, 金属Ag颗粒沉积在TiO 2表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m 2·g -1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO 2对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性. 相似文献
15.
以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N 2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO 2皆为锐钛矿相, 金属Ag颗粒沉积在TiO 2表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m 2·g -1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO 2对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性. 相似文献
16.
以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N 2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO 2皆为锐钛矿相, 金属Ag颗粒沉积在TiO 2表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m 2·g -1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO 2对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性. 相似文献
17.
Atomic‐layer deposition (ALD) is a thin‐film growth technology that allows for conformal growth of thin films with atomic‐level control over their thickness. Although ALD is successful in the semiconductor manufacturing industry, its feasibility for nanoparticle coating has been less explored. Herein, the ALD coating of TiO 2 layers on ZnO nanoparticles by employing a specialized rotary reactor is demonstrated. The photocatalytic activity and photostability of ZnO nanoparticles coated with TiO 2 layers by ALD and chemical methods were examined by the photodegradation of Rhodamine B dye under UV irradiation. Even though the photocatalytic activity of the presynthesized ZnO nanoparticles is higher than that of commercial P25 TiO 2 nanoparticles, their activity tends to decline due to severe photocorrosion. The chemically synthesized TiO 2 coating layer on ZnO resulted in severely declined photoactivity despite the improved photostability. However, ultrathin and conformal ALD TiO 2 coatings (≈0.75–1.5 nm) on ZnO improved its photostability without degradation of photocatalytic activity. Surprisingly, the photostability is comparable to that of pure TiO 2, and the photocatalytic activity to that of pure ZnO. 相似文献
18.
以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N 2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO 2皆为锐钛矿相, 金属Ag颗粒沉积在TiO 2表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m 2·g -1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO 2对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性. 相似文献
19.
以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N 2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO 2皆为锐钛矿相, 金属Ag颗粒沉积在TiO 2表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m 2·g -1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO 2对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性. 相似文献
20.
以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N 2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO 2皆为锐钛矿相, 金属Ag颗粒沉积在TiO 2表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m 2·g -1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO 2对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性. 相似文献
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