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The effects of grain size, space velocity, temperature and reactant concentration on the kinetics of NOx reduction with propane over Co-β-zeolite catalyst were investigated. The external mass transfer phenomenon was examined by varying the space velocity. The results show that the transfer can be negligible when the space velocity is greater than 60000 h-1 in low temperature range. However, the transfer exists at high temperatures even when the space velocity reaches a high level.Variation of the catalyst grain size from 0.05 to 0.125 mm does not change the conversion rate of NOx. The concentrations of components, NOx, C3H8 and O2, were also investigated to have a better understanding of mechanism. Based on the experimental data, the selectivity formula was proposed. The results shows that lower temperature is helpful to get higher selectivity as the activation energy of hydrocarbon oxidation, Ea,2, is greater than that of NOx reduction, Ea,1, (Ea,2>Ea,1). High NOx concentration and low C3H8 concentration are beneficial to high selectivity. However in order to maintain high activity simultaneously, the temperature and C3H8 concentration should be high enough to promote NOx reduction. 10%(ψ) H2O and 75×10-6(ψ) SO2 were introduced into the reaction system, and Co-β-zeolite shows strong resistance to water and SO2. 相似文献
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光电一体化处理杀扑磷农药废水 总被引:5,自引:0,他引:5
为了解决有机磷农药引起的严重环境污染问题,采用一种新的催化氧化方法--光电一体化高级氧化工艺,处理杀扑磷农药废水.实验表明,光电结合能有效地降低废水的化学需氧量(COD),与单独光催化和单独电催化相比,杀扑磷的降解效率大大提高,且存在协同作用,协同效率可达96%.加入少量电解质后,废水COD去除率迅速提高到80%以上.光电催化过程产生大量强氧化性羟基自由基(·OH),诱发链反应产生,杀扑磷被有效降解,生成小分子有机酸,导致溶液pH值降低.由于NaCl在电解中产生氧化能力较强的ClO-,加入NaCl电解质比加入Na2SO4能更好地降低废水的COD.不同初始浓度对降解效率有较大影响,杀扑磷农药废水的降解符合表观一级动力学方程.光电结合能有效降低杀扑磷废水的毒性,适于作为高浓度难降解废水的预处理过程. 相似文献
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The effects of grain size, space velocity, temperature and reactant concentration on the kinetics of NOx reduction with propane over Co-b-zeolite catalyst were investigated. The external mass transfer phenomenon was examined by varying the space velocity. The results show that the transfer can be negligible when the space velocity is greater than 60000 h-1 in low temperature range. However, the transfer exists at high temperatures even when the space velocity reaches a high level. Variation of the catalyst grain size from 0.05 to 0.125 mm does not change the conversion rate of NOx. The concentrations of components, NOx, C3H8 and O2, were also investigated to have a better understanding of mechanism. Based on the experimental data, the selectivity formula was proposed. The results shows that lower temperature is helpful to get higher selectivity as the activation energy of hydrocarbon oxidation, Ea,2, is greater than that of NOx reduction, Ea,1, (Ea,2>Ea,1). High NOx concentration and low C3H8 concentration are beneficial to high selectivity. However in order to maintain high activity simultaneously, the temperature and C3H8 concentration should be high enough to promote NOx reduction. 10%(j) H2O and 75′10-6(j) SO2 were introduced into the reaction system, and Co-b-zeolite shows strong resistance to water and SO2. 相似文献
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Chlorinated organic compounds, especially chlorophenols are well-known water priority pollutant family due to their toxicity and potential health hazard. As biological treatment processes for the degradation of chlorinated phenols have not been effective, various technologies and processes such as activated carbon adsorption[1], chemical oxidation[2], have been conventionally attempted for phenolic waster treatment. Recently, advanced oxidation processes (AOPs) have attracted a great deal of attention for treatment of phenolic wastewater, among these chemical oxidation ultraviolet (UV) oxidation system[3], anodic oxidation and indirect electro-oxidation have been widely studied[4]. Though a number of researchers worked on the degradation of chlorophenol by UV radiation or electrochemical processes, there are few reports on both methods for organic wastewater treatment. If these two processes can operate in harmony, the degradation efficiency would be enhanced. 相似文献
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Chlorinatedorganiccompounds,especiallychlorophenolsarewell -knownwaterprioritypollutantfamilyduetotheirtoxicityand potentialhealthhazard .Asbiologicaltreatmentprocessesforthedegradationofchlorinated phenolshavenotbeeneffective ,varioustechnologiesand proc… 相似文献
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