| Summary: | 碩士 === 朝陽科技大學 === 環境工程與管理系碩士班 === 95 === Acid flushing and excavation are commonly used for removing heavy metals from soil, but acid flushing thus creates the serious destruction to the soil structure and soil organic matter and fertility draining. Therefore this research is to use the acid flushing and chelating agents (chitosan) to discuss the removal efficiency of heavy metals from soil, after as well as flushing to soil fertility maintenance efficiency. In this work the development of a process for the remove of cadmium from contaminated industrial soils is presented. Experimental tests on soil mixed with 0%, 0.5%, 2%, 3.5% and 5%(w/w) high molecular weight Chitosan were carried out. First 10-1M and 10-7M HCl solution carries on the batch of tube level isotherm temperature extract experiment. According to the result of the extract experiment, when the extract time amounts to 120 minutes, increases chitosan may promote the extract efficiency. The metal was extracted from the contaminated soil by flushing with 10-1M, 10-3M and 10-7M HCl. Results illustrated that because the soil pH value reduces, therefore the cadmium dissolves the effect to be extremely good for 10-1M HCl, a maximum cadmium extraction efficiency of about 98% was observed. Hydrodynamic conductivity and cadmium mobilization decrease with the increase of weight percentage Chitosan. 10-3M HCl is also proved effective in the case of cadmium and kept pH of soil in neutral range. On the other hand, the effective of 10-7M HCl in the order 3.5%＞0.5%＞0%＞5%. Increase chitosan to column may retain a higher organic matter and the fertility element.
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