Sorption kinetics of toluene in humic acid: a computational approach.
Molecular dynamics, a computational technique aiming to describe the time-dependent movement of molecules, has been applied to study the sorption kinetics of volatile organic contaminants in soil organic matter. The molecular dynamics simulation results obtain reasonably accurate estimates of diffusion rates and activation energy of the penetration of a volatile organic compound molecule into a model humic substance. The sorption rate of toluene to humic acid decreases with the density of the humic acid matrix and increases with temperature. All the present results indicate that the sorption of toluene into humic acid is mainly diffusion controlled. Finally, the present studies have shown that molecular dynamics of volatile organic compounds in humic substances yields meaningful results, which help in the understanding of diffusion at the molecular level and which facilitate the problem-solving capability for removing the contaminants from the soils.
Shih
Yang-Hsin
YH
Department of Soil and Environmental Sciences, Center of Nanoscience and Nanotechnology, National Chung Hsing University 250, Kuo-Kuang Road, Taichung 402, Taiwan, Republic of China. yhs@nchu.edu.tw
Wu
Shian-Chee
SC
Lin
Jyh-Shing
JS
Lee
Lien-Feng
LF
D000327:Adsorption; D004058:Diffusion; D006812:Humic Substances; D007700:Kinetics; D008956:Models, Chemical; D015394:Molecular Structure; D012989:Soil Pollutants; D013816:Thermodynamics; D014050:Toluene / Q000737:chemistry*; D014835:Volatilization
D006812:Humic Substances; D012989:Soil Pollutants; D014050:Toluene