土壤有機質對土壤/水系統中低濃度非離子有機污染物吸附行為之研究

• Main Authors: Huang Huei-Chen, 黃慧貞
• Other Authors: 李俊福
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/46702573876900815763

碩士 === 國立中央大學 === 環境工程研究所 === 89 === In aqueous solution, the sorption of nonionic organic compounds (NOCs) on soil/sediment occurs mainly by partition into the soil organic matter (SOM) because the adsorption on soil mineral fraction is strongly suppressed by water. Recently, many researchers have been speculated that the sorption of NOCs on some soils displays a nonlinear sorption isotherm at relatively low concentration. The nonlinear uptake of a solute by soils at low NOCs concentration may be suppressed by other solutes (i.e., cosolutes) in multiple-solute systems. These observations indicate that more than one mechanism are required to account for the sorption of SOM. A series of single-solute and binary-solute sorption experiments were conducted for the sorption of nonionic organic compounds on three soil samples and two washed soil samples. The data were extended to relatively low solute concentrations (Ce/Sw) where Ce and Sw are the equilibrium concentration and solubility in water, respectively. At about Ce/Sw＝10-4, the nonionic organic solutes exhibit nonlinear sorption isotherm (of a concave-downward shape). The nonlinear uptake of a solute at low Ce/Sw is suppressed to different extents by other cosolutes in binary-solute system. The abilities of different cosolutes to suppress the nonlinear magnitudes depend on the molecular weight. The washed soils show different curvature on each adsorbate. These results in agreement with the hypothesis that adsorption on a small amount of strongly adsorbing HSACM is largely responsible for the nonlinear sorption of nonionic organic solutes on soils.