赤泥负载金属氧化物催化剂的制备及其脱硝性能研究

发布时间：2018-05-30 23:28

本文选题：脱硝催化剂 + 氮氧化物　；参考：《济南大学》2015年硕士论文

【摘要】：近年来,随着工业和经济的快速发展,大量燃料的燃烧及机动车尾气的大量排放导致氮氧化物的危害日益严峻。氮氧化物(NOx)是造成酸雨、臭氧层破坏和光化学烟雾的主要污染物之一,对自然环境和人类健康都有着很大的危害。关于氮氧化物的去除,目前研究最广泛也最有应用前景的是以NH3为还原剂选择性催化还原(NH3-SCR)技术。而NH3-SCR技术的核心就是催化剂,应用最广泛的就是V2O5-WO3/TiO2体系催化剂,该类催化剂虽然脱硝活性高,但该类催化剂存在活性温度高、成本高,活性组分钒氧化物有剧毒等缺陷。赤泥作为铝厂的工业废渣,因具有强碱性其引起的环境污染问题不容忽视。基于赤泥本身含有大量的氧化铁、氧化铝、氧化硅、氧化钛等组分,这些组分对脱硝都有一定的促进作用:其中铁氧化物具有很好的催化脱硝活性,氧化铝、氧化硅是被广泛研究的脱硝催化剂的载体,因此赤泥为基础制备脱硝催化剂的研究具有一定的可行性,作为脱硝催化剂的研究具有实际的应用意义。此外赤泥含有大量的碱性组分Na、Ca等,阻碍其工业化应用,因此还需要对赤泥进行一定的预处理方可实现其催化脱硝应用。本论文采用铝厂工业废渣赤泥为原料,经过预处理后负载金属氧化物活性组分,制备了一系列赤泥脱硝催化剂。利用X射线粉末衍射(XRD)对赤泥的物相进行了确认,结果显示赤泥中主要物种是Fe2O3、SiO2、TiO2、Al(OH)3等物种,通过X射线荧光光谱仪(XRF)进一步证明了赤泥中含有大量的Fe、Al、Si等的氧化物。对赤泥的预处理结果表明预处理不仅降低了赤泥碱含量,而且大大提高了赤泥的比表面积,改善了赤泥的孔结构,提高了脱硝活性。赤泥的预处理工艺简单经济,预处理赤泥在催化领域有很好的应用前景。向赤泥上负载不同金属氧化物组分后,活性评价结果表明,相比Mo、Co、Ni的氧化物,V和Cu的氧化物负载的赤泥具有更高的脱硝活性。通过合成一系列不同负载量的V、Cu赤泥脱硝催化剂,考察了活性组分负载量对催化剂脱硝性能的影响,结果表明随着活性组分的增加,催化剂脱硝性能呈现先升高再降低的趋势,说明活性组分在赤泥表面上存在一个最佳负载比,这个比值随载体和活性组分不同而有所不同。本文采用比表面积分析仪、扫描电子显微镜(SEM)、X射线衍射(XRD)等表征技术研究赤泥脱硝催化剂的形貌及微观结构;利用H2程序升温还原技术研究催化剂的氧化还原性能;结合NO-TPD和原位红外的研究结果,分析探讨了催化剂的性能与结构之间的关系。综合上述性能测试结果,7Cu/PTRM催化剂的具有适宜的性能,展现出现有实验条件下最好的催化活性。
[Abstract]:In recent years, with the rapid development of industry and economy, the combustion of a large amount of fuel and a large number of vehicle exhaust emissions lead to the increasingly serious harm of nitrogen oxides. Nitric oxide (NOX) is one of the main pollutants causing acid rain, ozone depletion and photochemical smog, which is harmful to natural environment and human health. As for the removal of nitrogen oxides, the technology of selective catalytic reduction of NH _ 3-SCR with NH3 as reducing agent is the most widely studied and most promising. The core of NH3-SCR technology is catalyst, and the most widely used catalyst is V2O5-WO3/TiO2 system catalyst. Although this kind of catalyst has high denitrification activity, but this kind of catalyst has the defects such as high activity temperature, high cost and so on, the active component vanadium oxide has the extremely toxic and so on. Red mud, as the industrial waste residue of aluminum plant, can not be ignored because of its strong alkalinity. Based on the fact that the red mud itself contains a lot of iron oxide, alumina, silicon oxide, titanium oxide and so on, these components can promote denitrification to a certain extent: iron oxides have good catalytic denitrification activity, alumina, Silicon oxide is a widely studied carrier of denitrification catalyst, so it is feasible to study the preparation of denitrification catalyst based on red mud, and the research as a denitrification catalyst has practical application significance. In addition, red mud contains a large amount of basic components, such as Na ~ (2 +) Ca, which hinders its industrial application. Therefore, it also needs some pretreatment to realize the application of catalytic denitrification of red mud. In this paper, a series of red mud denitrification catalysts were prepared by using red mud from industrial waste residue of aluminum plant as raw material and loading active components of metal oxides after pretreatment. The phase of red mud was confirmed by X-ray powder diffraction (XRD). The results showed that the main species in red mud were Fe2O3SiO2SiO2O2O2AlOOHHH3. The results of X-ray fluorescence spectrometer (XRF) further proved that the red mud contained a large amount of oxides such as Feo Al Si and so on. The pretreatment results showed that the pretreatment not only reduced the alkali content of red mud, but also greatly improved the specific surface area, pore structure and denitrification activity of red mud. The pretreatment process of red mud is simple and economical. After loading different metal oxides on the red mud, the results of activity evaluation showed that the red mud had higher denitrification activity than that of the red mud loaded with the oxides of Mo-Co-Ni and Cu. Through the synthesis of a series of VGU red mud denitrification catalysts with different loading amounts, the effect of the active component loading on the denitrification performance of the catalyst was investigated. The results showed that the denitrification performance of the catalyst increased first and then decreased with the increase of the active component. It is concluded that there is an optimum loading ratio of active components on the surface of red mud, which varies with the carrier and active components. In this paper, the morphology and microstructure of red mud denitrification catalyst were studied by means of specific surface area analyzer and scanning electron microscope (SEM), and the redox performance of the catalyst was studied by H 2 temperature programmed reduction technique. Based on the results of NO-TPD and in situ IR, the relationship between the performance and structure of the catalyst was analyzed and discussed. The results show that the 7Cu / PTRM catalyst has the best catalytic activity under the experimental conditions.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;X701

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