整体式催化剂活性组分负载策略及微波催化燃烧甲苯特性

Loading strategy for the active components of monolithic catalyst and its influences on the microwave enhanced catalytic combustion of toluene

针对催化剂活性组分脱落问题,采用载体预处理和添加硅溶胶的策略来强化活性组分负载,微波单模腔中催化燃烧甲苯以考察催化剂活性,并对牢固负载的催化剂进行表征分析。研究表明,常温下采用10%盐酸溶液对蜂窝状堇青石(CH)载体预处理、硅溶胶添加量与载体吸水量比值为0.125条件下所制备的Cu-Mn-Ce(硅溶胶)/CH催化剂脱落率为0.0129%,明显低于Cu-Mn-Ce/CH催化剂的0.950%。Cu-Mn-Ce(硅溶胶)/CH催化剂具有更小的活性颗粒尺寸、更大的比表面积和更多样的活性晶体,在甲苯进气浓度1000mg/m^3、进气量0.12m^3/h、微波功率200W和床层温度350℃条件下,催化剂对甲苯的催化燃烧效率和矿化率分别为98.5%和87.9%;连续实验43h后,催化剂活性保持稳定且活性组分脱落率低(0.0328%)。硅溶胶的添加增强了活性组分与载体之间的相互作用力,生成的硅氧烷化学键提高了活性组分的结合牢固度。

Aiming at solving the shedding problem of active components,a loading strategy that includes carrier pretreatment and addition of silica sol was adopted to strengthen the combination of the active components with the carrier.Catalytic activity of the catalyst was investigated in toluene combustion by using microwave single-mode cavity,and high-firmness catalysts were characterized subsequently.The study showed that the shedding rate of Cu-Mn-Ce(silica sol)/cordierite honeycomb(CH)catalyst prepared under conditions of 10%hydrochloric acid pretreatment at room temperature and 0.125 of the mass ratio of silica sol to water absorption amount of CH carrier was 0.0129%,which was much lower than 0.950%of Cu-Mn-Ce/CH catalyst.Cu-Mn-Ce(silica sol)/CH catalyst had smaller active particles,larger specific surface area and more active crystals than Cu-Mn-Ce/CH catalyst.Under conditions of 1000 mg/m^3 of initial concentration,0.12 m^3/h of air flow,200 W of microwave power and 350℃of bed temperature,the removal and mineralization rates of toluene by Cu-Mn-Ce(silica sol)/CH catalyst were 98.5%and 87.9%,respectively.The Cu-Mn-Ce(silica sol)/CH catalyst owned high catalytic activity and stability after 43 h run,and the shedding rate of active components was 0.0328%.The addition of silica sol could enhance the interaction forces between the active components and the catalyst carrier,and the formation of siloxane chemical bonds could greatly improve the connection of active components to prolong the service life of the catalyst.