Adsorption kinetics of toluene on soil agglomerates: Soil as a biporous sorbent

被引:25
作者
Arocha, MA [1 ]
Jackman, AP [1 ]
McCoy, BJ [1 ]
机构
[1] UNIV CALIF DAVIS,DEPT CHEM ENGN & MAT SCI,DAVIS,CA 95616
关键词
D O I
10.1021/es9504294
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
Single-component vapor diffusion at low pressure into dry soil agglomerates provides a well-characterized system for investigating adsorption and diffusion mechanisms. Equilibrium and kinetic data for adsorption of toluene vapor on Yolo loam and montmorillonite clay were obtained in this study with a gravimetric method. More extensive equilibrium data were obtained with a headspace gas chromatographic technique. Freundlich isotherms provided a good fit to the equilibrium data for relative partial pressures less than 0.6. Adsorption of toluene from the gas phase occurred in two stages: the first was due to fast diffusion and adsorption in macropores, and the second was controlled by slower diffusion and adsorption in intragrain micropores. As several days are required to establish equilibrium, the effect of slow diffusion and adsorption would be overlooked in shorter studies. Numerical simulations described the isothermal adsorption of toluene on spherical soil particles subject to a step change in bulk concentration. Biporous diffusion models are necessary to interpret the distinct diffusional characteristics of toluene in macropores and micropores with nonlinear adsorption. The simulations quantitatively describe details of the adsorption history.
引用
收藏
页码:1500 / 1507
页数:8
相关论文
共 41 条
[1]   MODELING MULTICOMPONENT VOLATILE ORGANIC AND WATER-VAPOR ADSORPTION ON SOILS [J].
AMALI, S ;
PETERSEN, LW ;
ROLSTON, DE .
JOURNAL OF HAZARDOUS MATERIALS, 1994, 36 (01) :89-108
[2]  
[Anonymous], 1974, AICHE J
[3]  
AROCHA MA, 1995, THESIS U CALIFORNIA
[4]   LONG-TERM SORPTION OF HALOGENATED ORGANIC-CHEMICALS BY AQUIFER MATERIAL .1. EQUILIBRIUM [J].
BALL, WP ;
ROBERTS, PV .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1991, 25 (07) :1223-1237
[5]  
BALL WP, 1991, ENVIRON SCI TECHNOL, V25, P1227
[6]   SORPTION NONIDEALITY DURING ORGANIC CONTAMINANT TRANSPORT IN POROUS-MEDIA [J].
BRUSSEAU, ML ;
RAO, PSC .
CRITICAL REVIEWS IN ENVIRONMENTAL CONTROL, 1989, 19 (01) :33-99
[7]   SOIL SORPTION OF ORGANIC VAPORS AND EFFECTS OF HUMIDITY ON SORPTIVE MECHANISM AND CAPACITY [J].
CHIOU, CT ;
SHOUP, TD .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1985, 19 (12) :1196-1200
[8]  
Coates JT, 1986, J CONTAM HYDROL, V1, P191
[9]   DESCRIPTION OF TIME-VARYING DESORPTION-KINETICS - RELEASE OF NAPHTHALENE FROM CONTAMINATED SOILS [J].
CONNAUGHTON, DF ;
STEDINGER, JR ;
LION, LW ;
SHULER, ML .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1993, 27 (12) :2397-2403
[10]  
Crank J, 1979, MATH DIFFUSION