脱硫类水滑石衍生复合氧化物不同方法的制备与表征

Preparation by Different Methods and Characterization of Desulfurization Mixed Oxides Derived from Hydrotalcites

采用尿素水解法和共沉淀法制备了MgAl类水滑石,高温焙烧获得衍生复合氧化物.采用X射线衍射(XRD)、热重分析(TG-DTG)、扫描电镜(SEM)、N2-吸附/脱附和CO2程序升温脱附(CO2-TPD)等手段对所制备的复合氧化物结构特征进行表征,并研究其对SO2脱除性能的差异.结果表明,共沉淀法制备的MgAlO复合氧化物比尿素法具有更大的比表面积(148.1m2·g-1)和更多碱性位,这些特点可能促使该方法制备的复合氧化物具有更高的SO2储存容量和反应速率.采用尿素法和共沉淀法制备的MgAl水滑石复合氧化物在700℃温度下SO2吸附容量分别可达0.55g·g-1和0.79 g·g-1.

Hydrotalcite-based MgAl mixed oxides were synthesized by urea hydrolysis and constant-pH coprecipitation methods,and characterized by means of X-ray diffraction( XRD),thermal gravity analysis-differential thermal gravity( TG-DTG),scanning electron microscope( SEM), N2-adsorption / desorption and CO2temperature programmed desorption( CO2-TPD), and their adsorption performances for SO2were also tested. It was found that MgAl mixed oxides prepared by coprecipitation method would facilitate the catalyst to maintain a high specific area( 148. 1 m2·g- 1) and more basic sites,which resulted in higher SO2adsorption capacity and velocity. The SO2adsorption capacity of the mixed oxides prepared by urea hydrolysis and constant-pH coprecipitation methods were 0. 55 g·g- 1and 0. 79 g·g- 1respectively at 700℃.