摘要
BET理论为测量材料比表面积提供了极其有用的方法。在实际操作中,为减轻实验工作量,减少测量成本以及快速得到测量结果,多采用单点BET方法。单点BET方法与多点BET方法相比较,其相对误差大小不仅取决于被测材料本身的特性(c值),而且与单点法所选择的相对压力值大小有关。研究发现,采用单点BET方法测量比表面积时,在0.05<p/p0<0.35范围内单点法与多点法相对误差有一极小值,而这一极小值所对应的相对压力值大小随材料而异。无孔材料在0.25左右,中孔分子筛为0.20,普通活性炭及中微孔分子筛0.3,微孔活性炭为0.35。按照这一原则选择单点法的相对压力值,可使单点法与多点法的相对误差小于1%。
BET theory is useful for the measurement of material＇s surface area.Tne single point BET method is adopted frequently since it is quite convenient, economical and effective in practice. Tne relative error between the single point BET method and the multipoint point method is affected not only by material itself（e value）,but also by the parameter of relative pressure.Research shows that there is a minimum error value in the range of 0.05 〈 p/p^0 〈 0.35 when using the single point method. Furthermore, the relative pressure under this minimum value varies according to different matters.For non-pore matter p/p0 is 0.25, zeolite with middle-pore is 0.2,ordinary active coal is 0.3 and active coal with micro-pore is 0.35.According to the result,the relative error of surface area can be minimized greatly to less than 1% when using the single point BET method under the p/p^0 recommended above.
出处
《中国测试技术》
CAS
2006年第5期42-44,103,共4页
CHINA MEASUREMENT & TESTING TECHNOLOGY
关键词
单点BET方法
相对误差
相对压力
Single point BET method
Relative error
Relatlve pressure
