發(fā)布時間：2018-02-25 16:15

  本文關(guān)鍵詞： 催化氧化 甲苯 二氯甲烷 金屬氧化物 泡沫鎳　出處：《吉林大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：環(huán)境問題已成為當(dāng)今社會的焦點問題,治理空氣污染刻不容緩。揮發(fā)性有機(jī)物(VOCs)被認(rèn)為是造成空氣污染日益嚴(yán)重的主要原因。這類化合物不僅導(dǎo)致光化學(xué)煙霧的產(chǎn)生,更對人身健康有深刻的影響,治理消除空氣中的VOCs十分必要。目前應(yīng)用較廣的VOCs處理方法主要有吸附法和催化氧化法。吸附法較催化氧化法來說雖然更易執(zhí)行,但卻面臨著競爭吸附、吸附時間短以致不能完全吸附,還有吸附劑再生困難等問題。相比之下,采取催化氧化的方法對VOCs進(jìn)行處理,是更為徹底有效的方法。多種類型負(fù)載型貴金屬及金屬氧化物催化劑對VOCs氧化反應(yīng)表現(xiàn)出良好的催化性能。當(dāng)前,研究開發(fā)性能更加優(yōu)異、且廉價易得VOCs氧化催化劑備受關(guān)注。本論文主要采用不同方法制備了一些負(fù)載型過渡金屬氧化物催化劑,通過氮氣吸附脫附(BET)、X射線粉末衍射(XRD)、掃描電鏡(SEM)、程序升溫還原(TPR)、程序升溫脫附(NH3-TPD)等手段對催化劑材料進(jìn)行表征,并評價了其對兩類代表性VOCs化合物甲苯和二氯甲烷的催化氧化性能。論文的主要研究內(nèi)容和結(jié)果如下:以Al_2O_3為載體,采用濕法浸漬和沉積沉淀法制備了一系列負(fù)載型金屬氧化物催化劑。催化反應(yīng)評價結(jié)果表明:與對應(yīng)的只負(fù)載單一金屬氧化物組分的催化劑相比,負(fù)載二元金屬氧化物的催化劑對甲苯及二氯甲烷的完全氧化反應(yīng)表現(xiàn)出更高的催化活性。H2-TPR等表征結(jié)果證實:添加第二組分能夠影響催化劑的還原性能,提高活性組分在載體表面的分散性。由此可以認(rèn)為,對于Al_2O_3負(fù)載的金屬氧化物催化劑,通過采用適合的方法引入其它組分,能夠有效調(diào)整催化劑的氧化還原性能,繼而獲得性能更加優(yōu)異的VOCs氧化催化劑。以一種新型材料泡沫鎳為載體,采用檸檬酸溶膠-凝膠路線制備了幾種二元或三元過渡金屬氧化物負(fù)載型催化劑。結(jié)果表明:以Cu:Mn:Ce為1:1:1的溶膠凝膠涂覆制備的泡沫鎳負(fù)載型催化劑對甲苯完全氧化反應(yīng)表現(xiàn)出較為優(yōu)異的催化性能。其中,經(jīng)500℃空氣氛下焙燒制得的催化劑具有最佳的催化性能。在甲苯濃度為1000 ppm時,達(dá)到甲苯98%轉(zhuǎn)化率的溫度為260℃,明顯優(yōu)于其它類型催化劑。泡沫鎳載體具有的獨特的網(wǎng)狀的三維結(jié)構(gòu)、高的孔隙度和比表面積等特點,使其能夠有效的負(fù)載和分散引入的活性組分,從而使這類催化劑表現(xiàn)出優(yōu)異的催化性能。
[Abstract]:Environmental problems have become the focus of today's society, the control of air pollution is urgent. Volatile organic compounds (VOCs) are considered to be the main cause of the increasing air pollution. These compounds not only lead to the production of photochemical smog, It also has a profound impact on human health. It is necessary to remove VOCs from the air. At present, the most widely used methods for treating VOCs are adsorption and catalytic oxidation. Although the adsorption method is easier to implement than the catalytic oxidation method, However, it is faced with the problems of competitive adsorption, short adsorption time and difficulty in regeneration of adsorbent. In contrast, VOCs is treated by catalytic oxidation. Various types of supported noble metals and metal oxide catalysts show good catalytic performance for VOCs oxidation reaction. At present, the research and development performance is better. In this paper, some supported transition metal oxide catalysts were prepared by different methods. The catalyst materials were characterized by means of nitrogen adsorption and desorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), temperature programmed reduction (TPR), temperature programmed desorption (TPR), and temperature programmed desorption (TPD). The catalytic oxidation properties of toluene and dichloromethane, two kinds of representative VOCs compounds, were evaluated. The main research contents and results are as follows: using Al_2O_3 as the carrier, the catalytic oxidation of toluene and dichloromethane was studied. A series of supported metal oxide catalysts were prepared by wet impregnation and deposition. The catalyst supported on binary metal oxide showed higher catalytic activity for the complete oxidation of toluene and dichloromethane. The results showed that the addition of the second component could affect the reduction performance of the catalyst. The dispersion of active component on the surface of the support is improved. It can be concluded that the redox performance of the Al_2O_3 supported metal oxide catalyst can be adjusted effectively by introducing other components into the catalyst by appropriate method. Then VOCs oxidation catalyst with better performance was obtained. The catalyst was supported by nickel foam, a new material. Several binary or ternary transition metal oxide supported catalysts were prepared by citric acid sol-gel route. The results show that the foam nickel supported catalyst prepared by sol-gel coating with Cu:Mn:Ce = 1: 1: 1 is completely oxygen to toluene. The chemical reaction showed excellent catalytic performance. The catalyst calcined in air atmosphere at 500 鈩，

本文編號：1534232