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研究了四针状氧化锌晶须在紫外光照射条件下对甲基橙的降解活性,考查了甲基橙溶液初始浓度、催化剂浓度及种类等对光催化降解的影响,并初步探讨了其反应动力学.实验结果显示,四针状氧化锌晶须光催化降解反应基本符合一级动力学规律,光催化效果随着甲基橙初始溶液浓度的增加而降低,最佳浓度为2g/L,是一种降解效果优异的光催化材料. 相似文献
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采用黑索金为可爆药剂,用爆轰法制备出了类球形混晶纳米TiO2粉体,并对合成的纳米TiO2粉末进行了表征。以甲基橙为研究对象,紫外灯为光源,研究了甲基橙初始浓度、纳米TiO2用量、甲基橙溶液初始pH值、超声分散和光照时间对甲基橙降解率的影响。研究表明,所制备的纳米TiO2为锐钛矿、板钛矿和金红石组成的混晶体,平均粒度约为18nm。在氧化钛浓度固定的条件下,甲基橙溶液初始浓度越高降解率越低。随着氧化钛加入量的增加,甲基橙溶液的降解率先增大后减小,而氧化钛的加入量超过40.0mg/L后,甲基橙溶液的降解率又呈升高的趋势。超声波分散的纳米氧化钛的表观反应速率明显高于未经超声波分散的氧化钛的表观反应速率。随着光催化时间的延长,光转化率逐渐升高。 相似文献
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以纳米四针状氧化锌晶须(T-ZnOw)为光催化剂,以甲基橙为染料模型化合物,研究了T-ZnOw的光催化氧化降解性能.考察了甲基橙溶液的初始浓度、催化剂用量和粒径等因素对光催化氧化降解反应的影响.研究结果表明,纳米T-ZnOw光催化氧化降解甲基橙的反应遵循一级反应动力学规律;光催化剂纳米T-ZnOw的最佳用量为2g/L,此时经60min光催化降解后,甲基橙溶液的色度剩余率仅为8%;T-ZnOw粒子直径越小,光催化活性越高,效果越好.对比实验和重复实验结果表明,纳米T-ZnOw的光催化氧化降解效果比纳米TiO2和普通球形纳米ZnO粉体更好,是一种高效、长寿的光催化剂材料. 相似文献
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以甲基橙的光催化降解为探针反应,从表观降解率和TOC去除率两个指标评价了纳米TiO2样品在不同焙烧温度和反应气氛下的光催化活性.结果表明,400℃焙烧的锐钛矿型TiO2纳米粒子的晶粒尺寸为11.69nm,在光催化降解甲基橙的实验中表现出最佳的光催化活性.光催化反应进行20min后对甲基橙的表现降解率达98.99%,反应进行30min后对甲基橙水溶液TOC的去除率为79.36%,TOC的去除效果滞后于色度的去除.不通空气时,样品对甲基橙的降解率最差,降解速率明显滞后于通空气和O2的情况,且通O2的降解效果更好. 相似文献
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研究了陈化时间及涂膜层数对纳米TiO2膜光催化性能的影响,结果表明:陈化3d时,膜的光催化性能最高;涂膜层数为3时,甲基橙的处理效率最高。同时研究了纳米TiO2膜对水和甲基橙的吸附性能,结果表明:水和甲基橙存在竞争吸附,随着加入甲基橙浓度的增加,光电催化测得的积分电量减少,膜的光催化活性降低。用制备的纳米TiO2膜光催化降解甲基橙,效率最高可达92.9%;在一定条件下累积运行93.8h,降解率均在83%左右,表明制备的纳米TiO2膜有较高的光催化性能及较长的使用寿命。 相似文献
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以甲基橙的光催化降解效率为指标,采用超声浸滞法制备了N掺杂TiO2纳米管阵列(N-TNTs)。结果显示,将TiO2纳米管阵列(TNTs)浸入0.02mol·L-1尿素溶液中,超声浸泡6min,干燥后在400℃下煅烧2h可获得N-TNTs。SEM和XRD表征结果显示,TNTs与N-TNTs形貌相似,管径均约为125nm,且锐钛矿相和金红石相相混,在2θ为35°(100)处观察到TiN0.26的衍射峰。pH=1、光照时间为4h时,N-TNTs对甲基橙的降解率达93.9%。同时,甲基橙初始浓度越低,甲基橙降解率越高。且N-TNTs光催化降解甲基橙的反应过程为拟一级动力学过程。将N-TNTs应用于光催化降解制糖废水时发现,在强碱性环境中,N-TNTs对制糖废水的降解率最高,光照25h降解率达到87.71%。 相似文献
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采用溶胶–凝胶法在常压下经不同温度热处理制备了TiO2/SiO2复合气凝胶光催化剂,利用XRD、TGA和BET等手段对其微观结构进行表征,以甲基橙溶液光催化降解实验评价其光催化性能,研究了热处理温度对TiO2/SiO2复合气凝胶的微观结构及光催化性能影响规律.结果表明:随着热处理温度升高,TiO2/SiO2复合气凝胶中锐钛矿结晶度升高,晶粒尺寸增大,比表面积减小,使TiO2/SiO2复合气凝胶对甲基橙溶液的光催化降解活性呈现先升后降的变化趋势.当热处理温度为700℃左右,紫外光照20 min TiO2/SiO2复合气凝胶对甲基橙溶液的降解率达到95.4%. 相似文献
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以吐温-80(Tween-80)和司班-80(Span-80)为复合模板剂,采用溶胶-凝胶(sol-gel)工艺制得介孔TiO2。通过对甲基橙溶液进行光催化降解试验表明:模板剂的种类与用量、光照距离和甲基橙溶液的原始浓度等因素对所制得介孔TiO2试样的光催化活性产生明显的影响。实验结果证明,本研究所得介孔TiO2材料具有较高的光催化活性,500℃下煅烧5h制备的样品在2.5h内可使浓度为0.02g/L的甲基橙溶液降解率达到94.7%,明显高于市售纳米TiO2粉体的降解率78.1%;通过X-ray衍射分析获知所制TiO2为锐钛矿型。 相似文献
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TiO2 nanofiber consisting of 15 +/- 5 nm anatase grains was synthesized by hydrothermal treatment of fibrous hydrogen titanate precursor at 180 degrees C for 20 h. The hydrogen titanate precursor was synthesized by hydrothermal treatment of commercial P25 TiO2 powder in 10 M NaOH at 200 degrees C for 20 h followed by soaking in 0.1 M HNO3 to perform ion exchange between the as-synthesized Na titanate and H. By controlling pH of the solution during hydrothermal treatment of the hydrogen titanate precursor, pure anatase TiO2 nanofiber was obtained. Its band-gap energy determined from the onset of diffused reflectance spectrum was 3.19 eV which is equal to that of anatase TiO2 powder. The TiO2 nanofiber showed higher photodecomposition efficiency than the Cotiox KA-100 TiO2 but lower than the P25 TiO2. Photodegradation is the predominant process for 'Reactive blue 171' removal. 相似文献
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The beta-cyclodextrin-modified Ag-TiO2 core-shell nanoparticles were prepared by sodium borohydrate reduction of AgNO3 and the subsequent hydrolysis of the tetraisopropyl orthotitanate in an aqueous medium. Inversely in the preparation of beta-cyclodextrin-modified TiO2-Ag core-shell nanoparticles, first hydrolysis and then following reduction were carried out. The synthesized spherical core-shell nanoparticles were highly water-dispersible and had an average diameter in the range of 9 to 12 nm. A significant shifting of surface plasmon band was observed for the synthesized Ag-TiO2 and TiO2-Ag core-shell nanoparticles. On a model reaction, namely, the photodegradation of phenol by the UV light irradiation, the photocatalytic property of TiO2 nanoparticles was enhanced, when the Ag nanoparticle was embedded in the core of TiO2 nanoparticles but TiO2 nanoparticles coated by Ag shell decreased the photocatalytic property of TiO2 nanoparticles. The mechanism is ascribed to the surface plasmon characteristics of Ag in the core of the TiO2 nanoparticles under the acceleration by host-guest inclusion characteristics. 相似文献
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Kuo CS Tseng YH Lin HY Huang CH Shen CY Li YY Ismat Shah S Huang CP 《Nanotechnology》2007,18(46):465607
Carbon nanotube (CNT)-grafted TiO(2) (CNT/TiO(2)) was synthesized as an electrically conductive catalyst that exhibits redox ability under electrical excitation besides ultraviolet (UV) irradiation. The CNT/TiO(2) material was synthesized by a two-step process. Ni nanoparticles were photodeposited onto TiO(2) first. The Ni nanoparticles then served as seeds for the growth of CNTs using the chemical vapor deposition (CVD) of C(2)H(2). The CNT/TiO(2) nanocomposite exhibits strong oxidation activity toward NO gas molecules via both photocatalysis under UV irradiation and electrocatalysis under a DC?voltage of 500?V in dark conditions. 相似文献
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Renu Sankar Ravishankar Dhivya Kanchi Subramanian Shivashangari Vilwanathan Ravikumar 《Journal of materials science. Materials in medicine》2014,25(7):1701-1708
The titanium dioxide nanoparticles (TiO2·NPs) were synthesized utilizing Origanum vulgare under room temperature. The green synthesized TiO2 NPs excitation was confirmed using UV–Vis spectrophotometer at 320 nm. Scanning electron microscopy analysis showed TiO2·NPs are spherical in shape and connected with one another. Dynamic light scattering analysis results specified high stability in nanoparticles, with an average particle size of 341 nm. Fourier transform infrared spectroscopy peaks revealed the presence of bioactive functional groups in Origanum vulgare aqueous leaf extract much needed for the TiO2·NPs formation. X-ray diffraction spectra showed the TiO2·NPs are amorphous in nature. Furthermore, the green synthesized TiO2·NPs wound healing activity was examined in the excision wound model by measuring wound closure, histopathology and protein profiling, revealed significant wound healing activity in Albino rats. In conclusion, our results bared TiO2·NPs have delivered a novel therapeutic route for wound treatment in clinical practice. 相似文献
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