共查询到19条相似文献,搜索用时 93 毫秒
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纳米TiO2光催化氧化愈创木酚的降解机理 总被引:2,自引:1,他引:1
以木质素的模型物愈创木酚(G-M)为研究对象,采用自制的纳米TiO2作光催化剂,在一定的降解条件下对G-M光催化降解的动力学和机理进行了研究.实验表明G-M的光催化降解过程包括吸附和降解两部分,通过对G-M在TiO2表面吸附性能的测定,得到其吸附平衡常数,在此基础上运用L-H方程对G-M光催化降解的动力学方程进行讨论,得到降解反应动力学方程1/r=1.744/C 0.103 4.采用有机物特征功能团的显色法,对G-M光催化降解反应过程的中间产物进行了分析,推断在G-M降解反应过程中出现了开环、脱羧,最终完全分解矿化生成二氧化碳和水. 相似文献
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纳米二氧化钛光催化降解苯酚水溶液 总被引:15,自引:1,他引:14
以P 25纳米TiO2 作为光催化剂,在环状光催化反应器中进行了苯酚水溶液的光催化降解性能研究。系统考察了溶液的pH、P 25用量、银掺杂量、苯酚的初始质量浓度等因子对苯酚溶液光催化降解过程的影响。结果表明,在pH=7时,苯酚水溶液降解率达97 4%,强酸和强碱条件均不利于苯酚的降解;质量浓度50mg/L的苯酚水溶液,P 25用量为50mg,UV辐照30min时降解率为95 6%;质量浓度100mg/L的苯酚水溶液,P 25用量为150mg,UV辐照60min时降解率为95 4%;银掺杂P 25增加了其光催化活性,用质量分数为10%的硝酸银水溶液掺杂制备的复合光催化剂,苯酚的降解率比未掺杂时增加16 5%。 相似文献
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本文以罗丹明B(RhB)为目标降解物,研究了锐钛矿型纳米二氧化钛(TiO2)的光催化降解效率的影响规律。通过比较不同分散剂对纳米TiO2分散液的分散作用的差别,研究了分散剂对纳米TiO2的光催化降解效率的影响;同时,也探讨了固含量和溶液pH值等因素对纳米TiO2光降解效率的作用规律。结果表明:二氧化钛(TiO2)固含量为5 wt%、六偏磷酸钠为0.8%、pH值为5时,目标降解物罗丹明B(初始浓度2.5ppm)在3h后降解效率达到80.25%。将制备的光催化分散液喷涂在大理石瓷砖表面,48 h内降解甲醛效率达到86.9%。 相似文献
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XZ Li H Liu LF Cheng HJ Tong 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(7):774-781
A new photocatalyst, named TiO2 microspheres, prepared by a sol‐spraying‐calcination method, can freely suspend with air bubbling in its aqueous suspension and easily settle down from a water phase under gravity. The experimental results demonstrated that TiO2 microspheres had better adsorption capacity than conventional TiO2 powders, due to large surface area, large pore volume, and also a porous structure. The photocatalytic activity of TiO2 microspheres in aqueous suspension was evaluated using salicylic acid (SA) as a model substrate. It was found that the Langmuir–Hinshelwood model in its integral form described the kinetics of SA photocatalytic degradation in the TiO2 microsphere suspensions better than its simplified form as a first‐order reaction model, since the significant substrate adsorption on the catalysts was not negligible. The kinetics of SA photocatalytic degradation with different initial concentrations and pH was further investigated. The experiments demonstrated that the change of pH could significantly affect the adsorption of SA in the TiO2 microsphere suspensions. The effects of substrate adsorption rate and photoreaction rate on the overall performance of photocatalytic degradation is also discussed on the basis of experimental data. Copyright © 2004 Society of Chemical Industry 相似文献
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TiO2光催化降解有机物研究进展 总被引:4,自引:0,他引:4
概述了近几年国内用TiO2光催化降解染料废水、卤代有机物、农药废水等的研究情况,对光催化剂的制备改性及光催化反应器的设计也作了阐述。并提出了当前光催化研究需要解决的几个问题,对进一步扩大TiO2光催化降解有机物的实际应用展示了广阔的前景。 相似文献
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研究了在UV/TiO2悬浮体系中光催化降解碱性品红。考察了碱性品红浓度、悬浮液pH值和外加无机盐对降解效果的影响。实验结果表明,当碱性品红质量浓度分别为20.0mg/L,30.0mg/L,40.0mg/L时,光照180min后,悬浮液中剩余的碱性品红质量浓度分别为1.8mg/L,2.3mg/L,3.4mg/L。pH=9.00时降解效果最好,当初始碱性品红质量浓度为30mg/L时,光照180min后,悬浮液中剩余的碱性品红质量浓度为0.8mg/L;pH=3.00的降解效果最差,光照180min后,悬浮液中剩余的碱性品红质量浓度为6.8mg/L;无机盐对降解效果有不同程度的负面影响。对降解机理的探讨表明光催化反应发生在光催化剂表面。 相似文献
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Chen Shifu Cheng Xueli Tao Yaowu Zhao Mengyue 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1998,73(3):264-268
The feasibility of photocatalytic degradation of trace gaseous acetone and acetaldehyde using TiO2 supported on fiberglass cloth was studied. The results show that gaseous acetone and acetaldehyde can be completely photocatalytically degraded into CO2 and H2O, after 35 min illumination with a 375 W medium pressure mercury lamp. The effects of parameters such as the flow of reactant gases and the concentrations of oxygen and water vapor in the feed stream on the photocatalytic degradation were studied. TiO2 supported on fiberglass cloth was not easily detached. After 150 h illumination there was no significant loss of the photocatalytic activity of TiO2. © 1998 Society of Chemical Industry 相似文献
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掺钒二氧化钛的可见光催化性能研究 总被引:6,自引:0,他引:6
制备高活性可见光响应型掺钒TiO2光催化剂,以荧光灯为光源,光催化降解亚甲基蓝为模型反应,对可见光下TiO2的催化活性进行评价。研究了掺钒TiO2制备方法、掺钒量及氧化剂对光催化氧化的影响。结果表明,溶胶-凝胶法制备的TiO2催化活性较高,且工序简单,钒离子掺杂均匀;掺钒能使TiO2具有可见光响应,最佳掺钒量为1%;外加氧化剂H2O2能提高掺钒TiO2催化活性。 相似文献