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Analytical models of the impact of two‐phase sorption on subsurface transport of volatile chemicals
Author(s) -
Shoemaker Christine A.,
Culver Teresa B.,
Lion Leonard W.,
Peterson Michele G.
Publication year - 1990
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr026i004p00745
Subject(s) - sorption , volatilisation , diffusion , water vapor , phase (matter) , environmental chemistry , vadose zone , chemistry , environmental remediation , groundwater , adsorption , thermodynamics , environmental science , soil water , soil science , organic chemistry , geotechnical engineering , contamination , geology , biology , ecology , physics
Unsaturated zone models incorporating the impact of vapor‐phase sorption on transport of volatile organic compounds are presented with closed form solutions for one‐ and two‐dimensional cases. In addition to vapor‐phase sorption the models incorporate liquid‐phase sorption, liquid advection, gaseous diffusion, and volatilization into soil air spaces and to the atmosphere. The motivation for incorporation of vapor‐phase sorption arises from recent experimental results by the authors indicating that vapor‐phase sorption may be orders of magnitude higher than liquid‐phase sorption under certain soil conditions. The sensitivity analysis suggests that there is considerable interaction among the physical and chemical processes involved in transport of volatile organic compounds. Pollutant concentrations are most affected by the Henry's law constant and gaseous diffusion; the speed of movement of the material depends most upon the pore water velocity and vapor‐phase sorption. The incorporation of vapor‐phase sorption can significantly reduce model predictions of the transport speed and amount of volatile chemical reaching the groundwater under dry soil conditions. This result is of considerable practical significance since models currently used for remediation and regulation do not include vapor‐phase sorption.