金属改性海泡石催化降解VOCs机理及过程研究

发布时间：2018-01-14 13:38

本文关键词：金属改性海泡石催化降解VOCs机理及过程研究　出处：《河北科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：挥发性有机物(VOCs)是生成PM_(2.5)和臭氧重要的前体物,是导致雾霾的主要污染物之一,所以对VOCs治理具有十分重要的意义。催化氧化法能够有效地在较低温度下将VOCs处理,高效高寿命的催化剂成为关键。低品海泡石是天然沸石的一种,具有一定的比表面积,同时价格低廉,但低品海泡石高附加值产品开发不足。针对以上情况,本文拟以改性低品海泡石为载体,负载过渡金属制备催化剂催化降解VOCs,优化催化剂的制备过程,研究最优海泡石催化剂降解甲苯的工艺,计算海泡石催化剂催化氧化甲苯的活化能。本研究首先通过酸和水热对低品海泡石进行预处理,提纯海泡石,对预处理后的海泡石进行XRD,TEM和BET表征,预处理后的海泡石纯度高,分散性好,比表面积有较大提升。采用共沉淀法,将铜、锰金属氧化物负载到海泡石上,制备铜锰改性催化剂。通过XRD,XRF,BET,TEM,EDX对催化剂进行表征以及活性测试。活性组分被负载到海泡石的表面以及孔道结构内部,活性组分为铜锰尖晶石。在尖晶石/海泡石催化剂中掺杂稀土元素铈,铈负载到海泡石催化剂上能够提高催化剂的催化活性,掺杂比例为0.2时催化效率最高。考察海泡石催化剂的寿命以及空速对海泡石催化剂的影响。对20%CuMn2Ce0.2/海泡石催化剂成型,对比HTS-1、ZSM-5、4A催化剂的催化活性,海泡石具有较好的性价比。采用基于氧化-还原机理的MVK模型建立海泡石催化剂催化降解甲苯的动力学模型,计算出20%CuMn2Ce0.2/海泡石催化剂的表面还原活化能为23.59kJ·mol-1,表面氧化活化能为26.07 kJ·mol-1。
[Abstract]:Volatile organic compounds (VOCs) are important precursors of PMS-2.5) and ozone, which is one of the main pollutants leading to smog. Therefore, it is very important for VOCs treatment. Catalytic oxidation can effectively treat VOCs at lower temperature. Low-grade sepiolite is one of the natural zeolites, which has a certain specific surface area and low price, but the low-grade sepiolite has not been developed enough. In this paper, the modified low-grade sepiolite was used as the carrier, supported on the transition metal catalyst to catalyze the degradation of VOCs, to optimize the preparation process of the catalyst, and to study the optimum technology of the sepiolite catalyst for the degradation of toluene. The activation energy of the catalytic oxidation of toluene over sepiolite catalyst was calculated. In this study, the low-grade sepiolite was pretreated by acid and hydrothermal method, then purified, and the pretreated sepiolite was treated with XRD. The results of TEM and BET showed that the pretreated sepiolite had high purity, good dispersion and high specific surface area. Copper and manganese oxides were loaded on the sepiolite by coprecipitation. Cu-Mn modified catalyst was prepared. The catalyst was characterized and its activity was tested by XRDX. The active components were loaded on the surface of sepiolite and inside the pore structure. The active component is copper-manganese spinel. Cerium doped in spinel / sepiolite catalyst can improve the catalytic activity of the catalyst. The effect of the lifetime of the sepiolite catalyst and the space velocity on the sepiolite catalyst was investigated. The 20 CuMn2Ce0.2 / sepiolite catalyst was formed. The catalytic activity of HTS-1 / ZSM-54a catalyst was compared. The MVK model based on redox mechanism was used to establish a kinetic model for the catalytic degradation of toluene over sepiolite catalyst. The surface reduction activation energy of CuMn2Ce0.2 / sepiolite catalyst is 23.59 kJ 路mol-1 and the surface oxidation activation energy is 26.07 kJ 路mol-1.
【学位授予单位】：河北科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X701

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