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刘祥英 《湖南农业大学学报(自然科学版)》2011,37(5):551-553
以高压汞灯为光源,研究纳米二氧化钛(TiO2)降解毒死蜱的反应动力学,考察纳米TiO2用量、毒死蜱起始质量浓度及溶液pH值对毒死蜱光催化降解速率的影响.结果表明,纳米TiO2最佳用量为50~100 mg/L,毒死蜱初始质量浓度在5~80 mg/L时,其降解反应符合一级反应动力学规律,表现为毒死蜱质量浓度越大,降解速率常... 相似文献
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Pt and Cr co doped Nano TiO2 film was prepared by the sol gel method. The film was characterized by AFM, XRD and UV Vis. The experiment showed that when the average TiO2 film diameter is 32 nm and the film thickness is 290 nm, the rate of photodegradation is 95% in 2.5 hours. Additionally, when the optimal co doping ratio for Pt Cr is n(Pt): n(TiO2) equals 0.03% and n(Cr):n(TiO2) equals 0.4%, the photodegradation of methylene blue for Nano TiO2 film can be enhanced. The photocatalytic properties of Pt and Cr co doped Nano TiO2 film is better than that of pure TiO2 and Pt, Cr separately doped TiO2 film. 相似文献
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Two kinds of Fe3+/TiO2 catalysts are prepared by Sol-gel method and hydrolysis method. XRD, UV-Vis, BET, curves of N 2 adsorption-desorption and 3D fluorescence are used to analyze the structures and properties of the catalysts, and their photocatalytic activities are investigated through degradation of DBP. The results show that two kinds of catalysts are anatase TiO 2. The band gap of the Fe3+/TiO 2 catalysts prepared by Sol-gel and hydrolysis method are 2.6 eV and 3.2 eV respectively, and the former with an absorption edge at 477 nm, while the latter with no redshift. The curves of N 2 adsorption-desorption of the Fe3+/TiO 2 catalysts prepared by Sol-gel and hydrolysis method are type Ⅳ and Ⅴ, their BET specific surface areas are 57.03 m2/g and 10.94 m2/g, and the hysteresis loop of the latter shifts to the high relative pressure region with a smaller pore volume and a bigger average pore diameter. Two kinds of catalysts can reduce photoluminescence properties of TiO 2 at various degrees, and the catalyst prepared by Sol-gel method shows a weaker photoluminescence property. The results of degradation experiment show the degradation rate of DBP by catalyst prepared by Sol-gel method and hydrolysis method are 60.53% and 31.83% respectively after 2 h. 相似文献
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光催化降解汽车尾气路面喷洒机的研究 总被引:1,自引:0,他引:1
根据光催化降解汽车尾气材料的喷洒要求及喷洒时所需的工作特点,结合我国实际的道路状况,研究设计光催化降解汽车尾气路面喷洒机。介绍喷洒机的结构组成及工作原理,对喷洒机的主要结构进行设计。该喷洒系统可利用牵引设备的动力或自载蓄电池来驱动直流电机液泵,取代传统的小型汽油机或柴油机,使该机工作时具备环保、低噪声和低振动等诸多优点。对喷洒机的试验方法进行研究,确定试验时的施工工艺,通过试验验证喷洒机的工作效果良好。 相似文献
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Five-membered nitrogen heterocycles (pyrrole, imidazole and 1,2,4-triazole) have been degraded using titanium dioxide and simulated solar radiation at pH = 8. The degradations followed a simple Langmuir-Hinshelwood mechanism. Accordingly, the adsorption equilibrium constants K of the heterocycles on the titanium dioxide surface and the rate constants k of degradation of the heterocycle-catalyst adduct have been obtained experimentally. While the K values decrease with heterocycle pKa, the k values increase with increasing pKa. Therefore, apparently, the rate constant depends on the availability of the electron pair on nitrogen, but at the same time the electron pair repulsion induced by the negatively charged titanium dioxide surface at pH = 8 causes a reverse effect in the adsorption equilibrium constant. Only in the case of imidazole, where the adsorption equilibrium constant is low enough (K = 0.013 M(-1)), can the rate constant be approximated to a pseudo-first-order rate expression: k(obs) = Kk. In all other cases, k(obs) = Kk/(1 + K(heterocycle)). 相似文献
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采用微波辅助光催化降解和直接光解实验方法,研究了苯噻草胺在光催化和直接光解两种体系下的降解情况,并考察了初始pH值、腐植酸浓度以及阿特拉津对其光催化降解和直接光解的影响。结果表明,在光照4min内,苯噻草胺直接光解效率为93.3%,较光催化降解效率高出28.9%;初始pH值从1.88增加至10.28时,苯噻草胺光催化和光解速率常数分别提高了250%和58.6%;添加腐植酸对苯噻草胺的直接光解和光催化均具有抑制效应,并且抑制效应随着腐植酸浓度的增加而增加,当腐植酸浓度增加至40mg·L^-1时,直接光解和光催化降解速率分别降低了51.8%和47.5%;10mg·L^-1的阿特拉津抑制了苯噻草胺的前期降解,整体直接光解速率降低了46.3%,但整体光催化降解速率没有减小。此外,采用GC—MS对苯噻草胺两种降解体系下的主要中间产物进行鉴定,并提出了主要的光降解途径。 相似文献
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【目的】探讨罗丹明B(RB)在Fe(Ⅲ)/UV/空气下的催化降解过程及其机理。【方法】在间歇式光反应器中,研究了pH分别为1.0,3.0和4.3,Fe(Ⅲ)质量浓度为1.68~28mg/L,RB的初始质量浓度为4~150mg/L时RB的光降解过程,通过抑制剂NaN3和异丙醇研究了降解过程可能发生的机理,同时测定了降解过程中Fe2+质量浓度的变化。【结果】RB直接UV光解和Fe(Ⅲ)/UV/空气下的降解表观动力学均符合表观一级动力学规律。RB在Fe(Ⅲ)/UV/空气下降解时,随Fe(Ⅲ)质量浓度的增加,RB降解速率常数增大,但增加程度受到pH的影响,pH=3.0时增加程度最大,pH=1.0次之,pH=4.3时最小;RB初始质量浓度增加,降解速率减小,当RB初始质量浓度高于20mg/L时,继续增加RB质量浓度对其光解速率影响不明显;反应过程中,Fe2+质量浓度在反应初期快速增加,此后维持在一定的水平。【结论】Fe(Ⅲ)/UV/空气能够快速催化RB光解,但在不同pH条件下,Fe(Ⅲ)催化UV光解RB的机理并不相同。 相似文献
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