摘要
运用 Langmuir分形吸附等温线方程模拟了颗粒活性炭对染料的吸附 ,得到了较好的效果 ,并且以染料分子作为码尺计算出颗粒活性炭的表面分形维数 Ds为 2 .5 90 2。染料在颗粒活性炭上的吸附动力学具有类分形特征 ,吸附反应的逐时速率系数 k与反应时间 t呈指数关系。但通过本文计算出的指数 h值无法计算出分形子谱维数
The present paper aims to introduce our investigation of the fractal adsorption characteristics of dye compounds on the granular activated charcoal. We also studied the adsorption isotherm and dynamic process through the related adsorption experiments of six kinds of dye compounds on the granular activated charcoal. The observed Langmuir fractal adsorption isotherm equation can be used to model the adsorption isotherm data between the charcoal and the dye compounds, and in turn the relative coefficients would exceed 0.9 and the dynamic index m could then be determined, which proves the applicability of fractal adsorption isotherm equation, and the fractal features of the charcoal's geometrical structure. The authors' research also shows that the molecular areas or radius of dye compounds could be calculated according to the relation between the molecular connective index ()~1χand the total surface molecular area (TSA). Based on the modeling results of m and the molecular section areas or radius of dye compounds, the surface fractal dimension D_sof the charcoal has worked out to be 2.590 2. Our calculation shows that the relative coefficient of regression line is about 0.7, but the linear tendency is predictable. Our analysis of adsorption dynamic data shows that the dynamics of dye compounds adsorbed onto granular activated charcoal is fractal-like. The dynamic relation existed between the rate coefficient (k) and reaction time(t). The exponent h is somehow quantitatively related with the spectral dimension (d_s) in literatures, giving the deviation from classical reaction dynamics, and the more the d_s values, the more the deviation. But most values of the calculated exponents (h) in this paper are more than one, and the spectral dimension (d_s) for fractal objects couldn't be calculated from them because of its being less than one of h value in the classic relation. Therefore, the literature relation can help to depict the simple molecular reaction dynamics, but the dye compounds have several functional groups reacting to active spots on granular activated charcoal surface. So the relation between h and d_s needs to be further studied.
出处
《安全与环境学报》
CAS
CSCD
2005年第1期23-26,共4页
Journal of Safety and Environment
基金
国家自然科学基金资助项目 (5 0 1780 0 9)
霍英东青年教师基金资助项目 (910 78)
关键词
环境科学
颗粒活性炭
吸附染料
分形维数
类分形动力学特征
environmental science
granular activated charcoal
adsorbing dye compounds
fractal dimensions
fractal-like dynamic characteristics
