【摘要】：揮發(fā)性有機(jī)化合物(VOCs)是一大類重要空氣污染物,其治理技術(shù)是目前國內(nèi)外研究熱點(diǎn)。催化燃燒被認(rèn)為是處理VOCs的一種有前景的技術(shù),高效催化劑是催化燃燒技術(shù)的關(guān)鍵。本文在實(shí)驗(yàn)室制備了用于揮發(fā)性有機(jī)物催化燃燒的鈰鋯固溶體催化劑,并通過第三種元素的摻雜以及雙元素?fù)诫s改性提高其催化性能,對制備的改性催化劑采用XRD、SEM、TEM、BET等微觀分析手段進(jìn)行了表征,考察了催化燃燒甲苯的影響因素。溶膠凝膠法制備的鈰鋯固溶體催化劑顆粒分散、催化效果好。在甲苯初始濃度為4000mg/m~3,空速為6000h~(-1)的條件下,鈰鋯比為0.6:0.4,焙燒溫度為550℃時(shí)制備出的Ce_(0.6)Zr_(0.4)O_2催化劑對甲苯有良好的轉(zhuǎn)化率。此時(shí)甲苯的起燃溫度T_(50)和完全轉(zhuǎn)化溫度T_(90)分別為302℃和352℃。XRD檢測表明,Zr~(4+)能進(jìn)入二氧化鈰的立方相晶格中形成鈰鋯固溶體。對于單一元素?fù)诫sCe_(0.6)Zr_(0.35)M_(0.05)O_2(M=Y、La、Mn、Cu)的鈰鋯固溶體。XRD表征表明這4種元素單獨(dú)摻雜形成了Ce-Zr-M三元固溶體,摻雜元素均勻分布在固溶體晶相中;單一元素?fù)诫s降低反應(yīng)起燃溫度效果為MnLaCuY;單一元素?fù)诫s的鈰鋯固溶體催化劑耐高溫性能為YMnLaCu。雙元素?fù)诫s發(fā)現(xiàn),同時(shí)摻雜Mn、Y的Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2催化劑在550℃焙燒以及950℃老化后都有著最優(yōu)的催化活性;550℃焙燒的Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2催化劑起燃溫度T50為260℃,完全轉(zhuǎn)化溫度T90為327℃;BET檢測表明摻雜改性后的鈰鋯固溶體比表面積有較大的提高,Ce_(0.6)Zr_(0.35)Mn_(0.05)O_2為140.37m~2/g,Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2為145.94m~2/g,而未摻雜改性的Ce_(0.6)Zr_(0.4)O_2只有87.3m2/g。Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2催化劑催化燃燒甲苯實(shí)驗(yàn)表明,甲苯的轉(zhuǎn)化率隨反應(yīng)溫度的變化呈現(xiàn)為S型上升;甲苯初始濃度為4000mg/m~3,焙燒溫度為550℃,顆粒粒徑為0.3-0.45mm區(qū)間內(nèi)的催化劑催化活性較高;空速低于9000h~(-1)時(shí),催化劑都能保持較高的甲苯轉(zhuǎn)化率;隨著水蒸氣濃度的增加,催化劑的催化效率降低。通過XRD、BET、SEM、TEM表征發(fā)現(xiàn)550℃焙燒的Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2催化劑保持了立方相結(jié)構(gòu),顆粒分布均勻,孔道為長圓柱型,孔徑大約為5nm,屬于介孔結(jié)構(gòu)。
[Abstract]:Volatile organic compound (VOCs) is an important class of air pollutants, and its treatment technology is a hot spot at home and abroad. Catalytic combustion is considered as a promising technology for VOCs treatment, and high efficient catalyst is the key of catalytic combustion technology. In this paper, cerium-zirconium solid solution catalyst for catalytic combustion of volatile organic compounds was prepared in laboratory. The catalytic performance of the catalyst was improved by doping the third element and two elements. The modified catalyst was modified by XRD,SEM,TEM,. BET and other microanalysis methods were used to characterize the catalytic combustion of toluene. The cerium-zirconium solid solution catalyst prepared by sol-gel method was dispersed and the catalytic effect was good. When the initial concentration of toluene is 4 000 mg / m ~ (-1) and the space velocity is 6 000 h ~ (-1), the cerium / zirconium ratio is 0.6: 0.4, The Ce_ (0.6) Zr_ (0.4) O _ 2 catalyst prepared at 550 鈩，

本文編號：2361853