活性炭分解臭氧机制研究

Effects and Mechanism of Catalytic Decomposition of Ozone by Activated Carbon

通过臭氧降解处理器尾气含量测定、温度测定和热量分析等研究了活性炭催化降解O3的效果和作用机制.结果表明,当O3的流量为12.89 mg.min-1,以充填2.0～2.5 mm煤质颗粒活性炭、直径18 mm玻璃柱为降解处理器,O3可以得到充分降解(分解效率始终维持100%),且效果可维持5 h以上.研究中发现活性炭催化降解处理器有升温现象,温度上升至65～69℃左右后,趋于平缓,期间CO2等氧化气体的释放量随温度稳定而减小.降解机制分为3部分:其一为活性炭发挥催化作用,活性炭的强烈吸附能力导致局部位置臭氧的富集和自身降解为氧气;其二为活性炭参与反应,臭氧破坏活性炭表面结构和基团,生成CO2和NOx等产物随尾气释放;其三为臭氧以上述2种机制降解形成氧气和各种氧化物时产热导致降解区域温度升高,进一步促进臭氧热降解.同时,还探讨了根据上述温度变化规律设计降解处理器的可能性.

Effects and mechanism of catalytic decomposition of ozone by activated carbon（AC） were studied by detection of residual components in released gas and temperature of reactor pole,and heat analysis through the ozone decomposition pole（ODP）.Results showed that ozone could be thoroughly decomposed（removal rate was maintaining 100% all along the process studied） for 5 h under the condition of O3 12.89 mg·min-1,18 mm diameter glass tube was stuffed by activated carbon（made from coal,2.0-2.5 mm diameter）.The temperature of ODP was found rise during the treatment.The temperature became stable after quickly rise to 65-69 ℃;and the CO2 output reduced with the stable temperature.The mechanisms of ozone decomposition were found including three parts.The first is catalytic decomposition by AC.AC enriches O3 and enhances O3 decomposition to form O2.The second is AC reaction with O3,which leads to destruction of the surface structure or group and output of CO2 and NOx are released with offgas.The third is temperature rising caused by heat production of CO2 and NOx formation according to the above two mechanisms,which enhances O3 thermal decomposition.Meanwhile,some basic design principles of ozone decomposition device were discussed.