【作者】 杨雪晶；

【导师】 韩一帆；

【作者基本信息】 华东理工大学 ， 化学工程， 2014， 博士

【摘要】 本论文提出了基于羟基自由基(HO·)生成速率和生成效率的非均相Fenton催化体系构筑思路,结合先进的材料可控制备技术与数值建模方法,对催化剂结构、反应性能、动力学及反应机理进行了研究。开发的体系可应用于水中微量污染物的高效降解清除。采用部分分解法和化学气相迁移法制备了层状氧基氯化铁(FeOC1)。结合降解活性与反应稳定性,对制备工艺和参数进行了优化。采用化学气相迁移法制备的FeOCl对10余种有机污染物进行了Fenton氧化降解,30min氧化降解率可达100%。采用5,5-二甲基毗咯啉氮氧化物(DMPO)捕捉电子顺磁共振(EPR)和苯甲酸分子探针动力学对FeOCl催化剂的HO·生成进行了定性和定量的研究,证明FeOCl催化剂的HO·生成速率高于传统含铁非负载型催化剂1-3个数量级。在此基础上采用熔融-浸润法成功将FeOCl固载于多种无机多孔载体,初步实现了催化剂工程化。制备工艺具有较高的可重复性和较好的规模性；同时简化了FeOCl催化剂的制备工艺,提高了FeOCl分散度和利用率。通过工程参数和数学拟合对HO·生成基元反应过程进行了详细分析,发现FeOCl可与H202形成活性络合中间体,从而控制产物的生成路径。针对H202分解中HO·的生成效率,设计了活性炭负载纳米金(Au/SRAC)催化体系。以双酚A为靶分子,对催化剂制备工艺参数、反应操作参数,分别包括载体处理方式、前驱体pH值、还原温度；反应pH值、温度、H202加入量等进行了单因素考察。结合多种表征技术建立了催化剂的构-效关系,认为纳米Au与碳上悬键的相互作用是催化活性的起源,进而产生金属与载体间电子极化或转移,改变了纳米Au与H202的作用路径,导致HO·的产生。针对H202催化分解,以拟一级速率模型为基础,研究了反应条件对表观动力学常数的影响。提出了基于双中间体的拟酶动力学模型,解释反应过程中HO.,以及自由基生成效率与反应条件之间的依赖关系。更多还原

【Abstract】 The development of solid Fenton-like catalysts and its application on the remediation of low-level organic compounds in water have been studied. With the combination of the new study strategy and experimental methods, the structure of the catalysts and its relationship with the performance on the remedy of wastewater were established. FeOCl with layer structure and the supported Au/C catalyst were prepared and used for the creation of hydroxyl radicals (HO) by the decomposition of hydrogen peroxide (H2O2).Various persistent organic compounds, which usually contaminated surface water even at ppm levels, was degraded in the developed Fenton-like FeOCl systems. Most of compounds can be degraded completely within30min. The HO-radicals were attributed to the Fenton activity, being verified by the DMPO-trapped EPR spectrum and themolecular probe methodThe generation rate of HO-over FeOCl was evaluated to be1-3orders of magnitude higher than that over other solid iron-containing minerals. Moreover, by a melt-infiltration method, the preparation route of supported FeOCl-based Fenton-like catalyst was prepared in a large scale. A kinetic modeling was built in the case of FeOCl/SiO2. The surface reaction rather than the diffusion process was dominated the decomposition process of H2O2. While the generation of HO-was demonstrated to be controlled by the decay of active complex formatted by FeOCl and H2O2.Moreover, a Au/C catalyst was also prepared and showed high HO-generation efficiency. Over a styrene-based activated carbon, uniformAu nanoparticles (NPs) wasdeposited by a modified ion-exchange method. The catalyst exhibited excellent activity for the Fenton degradation of bisphenol A. The affection of key factors, such as initial pH, reaction temperature, the loading amount of H2O2on the degradation of BPA and the decay of H2O2, were studied systematically. The structure-performance relationship of the catalyst was investigated by various techniques.The decay pathway was converted from double electron process to single electron process. The process of H2O2was further described by a set of elemental reaction network, namely a dual intermediates mechanism.更多还原