| Summary: | 碩士 === 國立中興大學 === 環境工程學系 === 87 === The toxicity potential of metals in the soils is dependent upon the ability of the metal desorption into the aqueous phase. The adsorption, desorption behavior of Cr（Ⅵ）, Hg, Pb, Cd, Ni, and Cu on five characterized Taiwan soils were studied. To simulate field conditions, the soils were subjected to various moisture and temperature conditions. Both adsorption and desorption measurements on the soils were conducted. The comparison between thermodynamic prediction model and empirical experimental results of temperature effect was applied.
All the experimental data showed, that the desorption amount of heavy metals in soils is far less than the amount of adsorption in 72 hours with various treatment conditions. The amount and rate of desorption were found to decrease with increasing number of cycles and decreasing temperature. In this study, the desorption results of six metals onto five soils collected in Taiwan via different temperatures proved that thermodynamic information almost can offer the reacting prediction in heterogeneous systems such as soil environment.
The wet-dry cycle and temperature effects on the desorption of metals from soils are related to the soil composition, with desorption being easiest from sandy soil with low organic content. The desorption process is much slower than the adsorption process. It is expected that researchful results will be beneficial to the remediation and suitable use of the soils with similar characteristics.
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