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等温吸附量方程常数的物理含义及无因次吸附量方程
陈元千,刘浩洋,汤晨阳,干磊
0
(中国石油勘探开发研究院,北京100083)
摘要:
LANGMUIR(兰格苗尔)于1918年发表的等温累积吸附量方程,描述了在等温条件下累积吸附量与吸附压力 之间的关系。然而,应当指出,兰氏方程是利用甲烷气、氮气、一氧化碳气、二氧化碳气、氧气和氩气等气体,在由云 母片制成的吸附仪上进行了大量等温吸附实验,在实验取得数据的基础上,提出的一个等温累积吸附量经验方程。 该方程具有a 和b 两个常数。陈元千等于2018年发表了等温累积吸附量方程的推导结果。该方程也存在A 和B 两 个常数。研究结果表明,陈氏和兰氏的等温累积吸附量方程的两个常数都具有重要的物理含义。陈氏方程的常数 A 和兰氏方程的常数a 都表示样品的极限累积吸附量;陈氏方程的常数B 和兰氏方程的常数b 都表示等温瞬压吸附 量递减率;陈氏方程的AB 和兰氏方程的ab 都表示样品的最大初始理论吸附量。同时,建立了陈氏和兰氏的等温无 因次累积吸附量方程和等温无因次瞬压吸附量方程,并提出了确定等温饱和吸附压力和等温饱和累积吸附量的方 法。通过16个实例应用,发现陈氏方程和兰氏方程评价样品的极限累积吸附量基本一致;对于等温瞬压吸附量递 减率和最大初始理论吸附量的评价,兰氏与陈氏的结果相差明显。但应当注意到,兰氏方程是一个经验方程,其可 靠程度要比陈氏方程低。
关键词:  等温  吸附量方程  方程常数  物理含义  无因次吸附量方程  饱和吸附量确定方法
DOI:10.13673/j.cnki.cn37-1359/te.2019.04.002
基金项目:
Physical meaning of adsorption isotherm constant and dimensionless adsorption isotherm equation
CHEN Yuanqian,LIU Haoyang,TANG Chenyang,GAN Lei
(PetroChina Research Institute of Petroleum Exploration & Development,Beijing City,100083,China)
Abstract:
The adsorption isotherm equation published by Langmuir in 1918 describes the relationship between cumulative adsorption rate and adsorption pressure under isothermal condition. However,it should be noted that the Langmuir equation is an empirical equation of isothermal cumulative adsorption based on the experimental data from a large number of adsorption isotherm experiments by adsorption instrument(made by mica sheet)using methane(CH4),nitrogen(N2),carbon monoxide(CO),carbon dioxide(CO2),oxygen(O2),argon(Ar),and other gases. This equation has two constants,a and b.CHEN Yuanqian published the derivation of adsorption isotherm equation in 2018. There are also two constants A and B for this equation. The research results indicate that the two constants in the adsorption isotherm equations proposed by Langmuir and CHEN both have important physical meanings. The constant A of CHEN’s equation and the constant a of Langmuir equation represent the limit of cumulative adsorption rate of the sample. The constant B of CHEN’s equation and the constant b of Langmuir equation represent the decreasing rate of adsorption capacity. AB of CHEN’s equation and ab of Langmuir equation represent the maximum of theoretical initial adsorption rate of the sample. Meanwhile,the dimensionless CHEN’s and Langmuir adsorption isotherm equation and adsorption isotherm equation at instantaneous pressure were proposed,and a method for determining the isothermal saturated adsorption pressure and isothermal saturated cumulative adsorption capacity was proposed. The application of 16 cases shows that the limit of adsorption rate of samples evaluated by CHEN’s equation and Langmuir equation was basically same. For evaluations of the decline rate of instantaneous pressure adsorption rate and the maximum theoretical initial adsorption capacity,the results of Langmuir equation were significantly different from those of CHEN’s equation. However,it should be noted that Langmuir equation is empirical,and its reliability is lower than CHEN’s equation.
Key words:  isotherm  adsorption equation  equation constant  physical meaning  dimensionless adsorption equation  determination method of saturated adsorption

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