铈锆固溶体催化剂催化燃烧甲苯的研究
发布时间：2018-11-27 19:47
【摘要】：挥发性有机化合物(VOCs)是一大类重要空气污染物,其治理技术是目前国内外研究热点。催化燃烧被认为是处理VOCs的一种有前景的技术,高效催化剂是催化燃烧技术的关键。本文在实验室制备了用于挥发性有机物催化燃烧的铈锆固溶体催化剂,并通过第三种元素的掺杂以及双元素掺杂改性提高其催化性能,对制备的改性催化剂采用XRD、SEM、TEM、BET等微观分析手段进行了表征,考察了催化燃烧甲苯的影响因素。溶胶凝胶法制备的铈锆固溶体催化剂颗粒分散、催化效果好。在甲苯初始浓度为4000mg/m~3,空速为6000h~(-1)的条件下,铈锆比为0.6:0.4,焙烧温度为550℃时制备出的Ce_(0.6)Zr_(0.4)O_2催化剂对甲苯有良好的转化率。此时甲苯的起燃温度T_(50)和完全转化温度T_(90)分别为302℃和352℃。XRD检测表明,Zr~(4+)能进入二氧化铈的立方相晶格中形成铈锆固溶体。对于单一元素掺杂Ce_(0.6)Zr_(0.35)M_(0.05)O_2(M=Y、La、Mn、Cu)的铈锆固溶体。XRD表征表明这4种元素单独掺杂形成了Ce-Zr-M三元固溶体,掺杂元素均匀分布在固溶体晶相中;单一元素掺杂降低反应起燃温度效果为MnLaCuY;单一元素掺杂的铈锆固溶体催化剂耐高温性能为YMnLaCu。双元素掺杂发现,同时掺杂Mn、Y的Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2催化剂在550℃焙烧以及950℃老化后都有着最优的催化活性;550℃焙烧的Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2催化剂起燃温度T50为260℃,完全转化温度T90为327℃;BET检测表明掺杂改性后的铈锆固溶体比表面积有较大的提高,Ce_(0.6)Zr_(0.35)Mn_(0.05)O_2为140.37m~2/g,Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2为145.94m~2/g,而未掺杂改性的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催化剂催化燃烧甲苯实验表明,甲苯的转化率随反应温度的变化呈现为S型上升;甲苯初始浓度为4000mg/m~3,焙烧温度为550℃,颗粒粒径为0.3-0.45mm区间内的催化剂催化活性较高;空速低于9000h~(-1)时,催化剂都能保持较高的甲苯转化率;随着水蒸气浓度的增加,催化剂的催化效率降低。通过XRD、BET、SEM、TEM表征发现550℃焙烧的Ce_(0.6)Zr_(0.3)Mn_(0.05)Y_(0.05)O_2催化剂保持了立方相结构,颗粒分布均匀,孔道为长圆柱型,孔径大约为5nm,属于介孔结构。
[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，
本文编号：2361853
[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，
本文编号：2361853
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