| Summary: | 碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程所 === 95 === Abstract
Thermogravimetric analysis (TGA) was used to perform thermal desorption experiments for a soil containing large concentrations of organic contaminants. Because TGA possesses the advantages of high sensitivity, small sample quantity requirement, quickness, and soil mass measurements under the temperature program of time-wise continuous record, TGA is highly effective in determining the thermal desorption parameters, such as the heating process and desorption temperature. By means of the parameters obtained from TGA, the effectiveness and feasibility of those desorption parameters were further evaluated with a bench-scale column thermal desorption apparatus.
A soil sampled from China Petrochemical Development Corp’s Anshun site was used for the TGA tests and column thermal desorption experiments. Results from TGA showed that four major mass-loss regions for contaminated soil were found: (1) region with temperatures between 30 and 120 ℃, mainly resulting from dehydration; (2) region with temperatures between 120 and 280 ℃, mainly resulting from a loss of organic matter; (3) region with temperatures between 280 and 550 ℃, mainly resulting from a desorption of pentachlorophenol (PCP) from soil, accompanied with the desorption of a minor potion of organic matter and dehydroxylation; (4) region with temperatures between 550 and 900 ℃, mainly resulting from a desorption of dioxin from soil. For column thermal desorption experiments, no residual PCP was observed in soil samples thermally treated at 550 ℃. Also, thermal desorption significant decreased the content of organic matter in contaminated soil. These results suggest that TGA can be successfully applied to determine the essential heating process/temperature for thermal desorption process at low to medium temperature; additional chemical analyses for untreated and treated soils may not be needed.
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