使用不同的氧化剂和不同的热处理温度对活性焦(AC)进行改性,采用低温N2吸附法、傅里叶变换红外光谱(FT-IR)、氨气-程序升温脱附(NH3-TPD)和非水酸碱滴定法对样品的孔结构和表面化学性质进了表征,并考察了样品在不同湿度下的NO常温催化氧化活性。结果表明,氧化改性减小了样品的微孔孔容,降低了样品的表面碱性基团含量和NO转化率。热处理改性则增加了样品的微孔孔容,提高了样品的表面碱性基团含量和不同湿度下的NO催化氧化活性。在相对湿度为0~80%范围内,氧化-热处理组合改性样品的NO转化率均高于活性焦直接热处理样品,且提高热处理温度,有利于增强样品在湿气(相对湿度为80%)条件下的NO催化氧化活性。
Commercial activated coke(AC) was modified with different oxidants and by heat-treatment at different temperatures. The pore structure and the surface chemical properties of the samples were characterized by N2 adsorption-desorption, FT-IR, NH3-TPD, and non-aqueous acid-base titration. The catalytic activity of NO oxidation on the samples at ambient temperature under different relative humidity was investigated. Results showed that both micropore volume and surface basic groups of the oxidized samples were decreased after oxidation modification,which resulted in the decline of NO conversion in the humid gas. The micropore volume and the content of surface basic groups of the heat-treated samples were increased obviously,which improved the resistibility of AC against the humidity during the NO oxidation process. In a relative humidity range of 0^-80% ,the oxidized samples followed by heat-treatment exhibited higher activity than that of the original AC modified with direct heat-treatment. And increasing the temperature of heat-treatment, the NO oxidation activity of the samples was enhanced in the humid gas (relative humidity 80%).