Sorption kinetics of selected volatile organic compounds in humin.
Each component of the chemically heterogeneous soil exhibits a unique sorption behavior toward organic sorbates. The sorption kinetics of some volatile organic compounds (VOCs) in pressed humin disks was investigated by tracking the weight change of the disks with a microbalance. Higher sorbing capacity for more polar VOCs as well as C13 nuclear magnetic resonance data indicates that humin was more hydrophilic than Aldrich humic acid (Milwaukee, WI, USA). The apparent diffusivity of acetone, toluene, and hexane in the disks ranged from 10(-8) to 10(-10) cm2/s. The sorbed toluene in humin does not seem persistent to desorption; however, acetone and hexane, either as polar or linear compounds in humin, show persistence against desorption. On completion of the desorption experiments, there were approximately 35 and 20% sorbate residue for acetone and hexane, respectively.
Shih
Yang-Hsin
YH
Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Republic of China. yhshih@mit.edu
Wu
Shian-Chee
SC
D000096:Acetone / Q000032:analysis*; D000327:Adsorption; D004058:Diffusion; D006586:Hexanes / Q000032:analysis*; D006812:Humic Substances / Q000737:chemistry*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D012989:Soil Pollutants / Q000032:analysis*; D014050:Toluene / Q000032:analysis*; D014835:Volatilization
D006586:Hexanes; D006812:Humic Substances; D012989:Soil Pollutants; C001861:humin; D000096:Acetone; C026385:n-hexane; D014050:Toluene