Cr-MnOx/堇青石催化剂制备及催化降解邻二氯苯性能研究

摘要

Cr-MnOx/cordierite composites were prepared by Sol-gel,Impregnation,Co-precipitation and Rheo-logical phase reaction method.Various technologies including X-ray diffraction (XRD),scanning electron mi-croscopy (SEM),energy dispersive spectrometer (EDS),thermogravimetry/differential scanning calorimetry (TG/DCS),and temperature-programmed reduction (TPR)were used to characterize the structure and mor-phology properties of the synthesized composites.The catalytic ability test of 1 ,2-dichlorobenzene (o-DCB) over the catalysts was conducted in a fixed-bed flow reactor with a gas hourly space velocity (GHSV)of 30, 000 h-1 to investigate the catalytic performance of the prepared composites.The results indicated that the com-bined Cr2 O3 and Mn2 O3 phases supported on cordierite possessed a special ball-shaped and better redox proper-ty in the catalyst prepared by the Co-precipitation method with a Cr/Mn atomic ratio of 2∶5 ,which was con-ducive to the increase of the synergistic effect and subsequently enhancement of the catalytic performance.Fur-thermore,it exhibited better stability within 60 h,which indicates a good prospect for industrial applications.%采用溶胶凝胶法、浸渍法、共沉淀法以及流变相法制备了新型 Cr-MnOx/堇青石催化剂,同时采用X射线衍射(XRD)、扫描电镜(SEM)、热重和差热分析(TG-DTA)、H2-程序升温还原(H2-TPR)以及元素能谱(EDS)技术对催化剂进行表征。经筛选发现,以共沉淀法制备的 Cr-MnOx/堇青石催化剂(Cr/Mn=2∶5)催化活性最高。通过表征结果可知,以共沉淀方法制备的催化剂主要活性成分为 Mn2 O3和 Cr2 O3,并且具有特殊的球形和较好的氧化还原性能,协同作用的存在有助于催化降解目标污染物邻二氯苯(o-DCB)性能的提高；在60 h之内,o-DCB降解率仍保持在80%以上,具有较好的催化稳定性。