【作者】 侯田锋；

【导师】 张孝彬； 杨杭生；

【作者基本信息】 浙江大学 ， 材料科学与工程， 2011， 硕士

【摘要】 随着环境污染问题的日益严峻,氯代芳烃及二恶英等高毒性有机污染物的排放控制和消除引起了学术界、工业界、政府和公众的普遍关注,因此通过低温催化氧化实现二恶英的零排放已成为各国科学家及工业界的追求目标。本论文以氯苯(注：实验室中二恶英替代物)为模型化合物,主要研究了MnOx/TiO2-CNTs、LaMnO3和LaVO4催化剂的制备及其对氯苯的催化氧化性能。研究了采用机械力化学(高能球磨)法制备的MnOx/TiO2-CNTs催化剂上氯苯的催化氧化性能。结果表明,该催化剂对氯苯有很好的催化氧化能力,在MnOx含量为20%时,300℃下对氯苯的催化氧化性能达到97.4%；同时,我们测试了空速和载体对MnOx/TiO2-CNTs催化剂的影响,以及催化剂在300℃下长期反应的稳定性。为了进一步提高催化剂在低温下对氯苯的催化氧化性能,我们对其进行了CeO2和V2O5掺杂,结果表明CeO2的加入提高了催化剂在低温下对氯苯的催化氧化性能,而V2O5加入使催化剂对氯苯的催化氧化性能降低。本文还研究了采用溶胶凝胶法制备的类钙钛矿型LaMnO3和LaVO4催化剂对氯苯的催化氧化性能。结果表明,在低温下LaMnO3催化剂对氯苯的催化氧化性能高于LaVO4催化剂,而当反应温度高于300℃时,LaVO4催化剂的活性高于LaMnO3。当用Sr部分取代La后形成的La0.8Sr0.2MnO3钙钛矿型催化剂,在低温下,对氯苯的转化率反而比LaMnO3催化剂低,而当反应温度在200℃以上时,La0.8Sr0.2MnO3催化剂的优越性能就体现出来了,温度越高La0.8Sr0.2MnO3催化剂的活性越好。当La0.8Sr0.2MnO3催化剂在300℃下活化12小时后,该催化剂在低温下对氯苯的转化率有了明显的提高。在反应温度为150℃时,La0.8Sr0.2MnO3催化剂对氯苯的催化氧化活性从67.9%提高到77.6%。此外,类钙钛矿型LaMnO3和LaVO4催化剂对氨有很好的催化氧化活性,在常压下,600℃对氨氧化成NOx的转化率分别为88%和95%。更多还原

【Abstract】 The emission abatement of toxic chemicals, such as chlorinated aromatics and polychlorinated dioxins/furans (PCDD/F) has attracted much attention from academia, industry, government and public with the growing environmental crisis; and the zero emission of dioxins through catalytic oxidation of dioxin-like compounds at low temperatures is a useful strategy and becomes the ultimate goal for scietists and industry. In this thesis work, the catalytic oxidation of chlorobenzene (CB), a common substitute material of dioxins in laboratory, on MnOx/TiO2-CNTs, LaMnO3 and LaV04 catalysts has been investigated.Catalytic oxidation of CB was tested over MnOx/TiO2-CNTs catalysts prepared by mechanical-chemical (high-energy ball-milling). The results show that, all the samples showed high catalytic activity for CB oxidation; among them the catalyst with 20wt%MnOx was identified as the most active one with an efficiency to destruct 97.4%of CB at 300℃. Moreover, effects of space velocity, and TiO2/CNTs supports on their catalytic activity and stability were also studied. To further improve the catalytic oxidation of CB at low temperature, we doped the catalyst with CeO2 and V2O5. The results showed that the doping of CeO2 increased the catalytic oxidation of CB, while the doping of V2O5 decreased the catalytic property at low temperature.Catalytic oxidation of CB was also tested over perovskite-type LaMnO3 and LaVO4 catalysts prepared by sol-gel. The results showed that the LaMnO3 catalyst presented higher catalytic oxidation of CB than LaVO4 catalyst at low temperature. While the reaction temperature was higher than 300℃, LaVO4 showed higher catalytic oxidation of CB than LaMnO3 catalyst. When Sr partial substituted for La to form Lao.8Sr0.2Mn03 perovskite catalyst, the conversion rate of CB was lower than LaMnO3 catalyst at low temperatures. But, when the reaction temperature was above 200℃, exhibited superior performance on catalytic oxidation of CB. After catalyst was activated at 300℃for 12 hours, the conversion of CB had been significantly improved at low temperature. The efficiency of catalytic oxidation of CB increased from 67.9%to 77.6%at 150℃. In addition, both of LaMnO3 and LaVO4 showed good activity for catalytic oxidation of NH3 to NOx. The NOx conversion achieved 88% and 95% for LaMnO3 and LaVO4, respectively at 600℃.更多还原