菲在土壤/沉积物上的吸附-解吸过程及滞后现象的研究

STUDIES ON SORPTION-DESORPTION EQUILIBRIA AND HYSTERESIS OF PHENANTHRENE BY SOIL AND SEDIMENT

实验研究了菲在土壤 /沉积物上的吸附 解吸过程。CHL土壤和HFH沉积物中有机质的固相13 CCPMASNMR谱图很相似 ,表明样品中有机质的组成差异不大 ;菲在土壤 /沉积物上的吸附过程表现出明显的非线性 ;线性模型不适合拟合菲的吸附等温线 ,Freundlich模型和双区位反应模型 (DRDM)较好地拟合了菲的吸附等温线 ,其中DRDM模型还清楚地反映菲在低浓度和高浓度下不同的吸附方式 ;另外 ,研究表明菲在土壤 /沉积物上的解吸过程中存在明显的滞后现象 ,这可能和土壤 /沉积物有机质的异质性和土壤胶团微小孔隙的存在有关。

This paper describes an experimental pursuit of a mechanistic model for interpreting and quantitatively describing nonlinear, slow, and hysteretic sorption phenomena associated with heterogeneous soils and sediment in subsurface systems. The soil/sediment organic matter was characterized using carbons types derived from 13 C CPMAS NMR spectroscopy. All sets of equilibrium sorption data were fitted using three different sorption model: the linear model, the Freundlich model or its linearized form, and the dual reactive domain model (DRDM). The linear model was not appropriate for describing any of the experimental sorption data, while the Freundlich model and the dual reactive domain model was found to be adequate for all samples. From DRDM it was observed that sorption mechanism changes with soil organic matter and with increasing contaminant concentration. The apparent sorption-desorption hystersis was quantified for each sample. Sorption-desorption hystersis each varie from sample to sample, and they also appear to correlate with the chemical characteristics of soil organic matter. On the other hand, the pore structure of soils may be a critical factor in sorption-desorption hystersis of hydrophobic organic contaminants.