热氧改性对活性炭物性影响的量化分析

Quantitative analysis of changes in physical properties of activated carbon with thermal and oxidating treatment

通过硝酸进行预处理,在不同氧气体积分数、温度、时间时对活性炭进行热氧改性,采用比表面积和孔径分析仪、SEM-EDX法对活性炭物性进行测试。采用BBD回应曲面法进行多元回归分析,建立改性条件与活性炭比表面积、微孔孔容、表面含氧量等参数关系的数学模型,探讨不同改性条件对活性炭物性的影响规律,对改性参数进行优化分析。研究结果表明:改性时间是活性炭比表面积和微孔孔容的最大影响因素,氧气体积分数是表面含氧量的最大影响因素。在制备良好的功能活性炭材料时,可以通过以下2种方式来实现:一是在氧气体积分数极低的环境中,适当提高改性温度与增加改性时间;二是增加改性气氛中的氧气体积分数,降低改性温度,同时缩短改性时间。

Activated carbon was modified by concentrated nitric acid at different oxygen concentrations, temperatures,and time. The physicochemical properties of the activated carbons were measured by specific surface area, pore distribution analyzer and SEM-EDX. BBD response surface method was applied to multiple regression analysis.Mathematical model of the relationship between the three modified conditions and activated carbon surface area,micropore volume, amount of oxygen groups was established, and the influence of the physical properties of activated carbon in different modified conditions was discussed and modified parameters were optimized. The results show that modification time is the biggest factor affecting the activated carbon surface area and micropore volume, and the oxygen concentration is the biggest factor affecting the surface oxygen content. Improving modified temperature and time appropriately at low concentration of oxygen is one way of making well-functional activated carbon. In addition,improving concentration of oxygen with the temperature and time reduced is another effective method.