| 摘要: | 隨著工業快速的發展，重金屬污染已形成了一種全球性的危害。存在於土壤及地下水中的重金屬，經由直接或間接的管道，造成環境及人體的傷害，因此，如何有效的處理地下水之重金屬污染之問題，已成為現今環工界之重要課題。地下水污染整治可分為「控制」及「處理」二個部分，而污染復育技術依污染地下水之取出與否可分為離地方法（ex-situ）及現地方法（in-situ）。在現地方法（in-situ）的應用上，由於透水性反應牆對於處理大範圍污染團具有其經濟效益，在美國已被廣泛接受為一有效之地下水整治技術。本計畫以綠色設計為概念，使用生物可分解之材料（幾丁聚醣），結合黏土中之膨潤土（Bentonite），進行為期二年之重金屬吸附研究。本研究延續前期研究之成果及經驗，以最佳合成之條件製備膨潤土─幾丁聚醣（Crosslinked Chitosan Immobilized on Bentonite）吸附劑，在室溫下（25 ºC）及50rpm 震盪速度下，進行多樣重金屬之基礎吸（脫）附研究，如：鉛（Pb）、鎳（Ni）、鋅（Zn）及鎘（Cd）等，並探討其在不同 pH 值、吸附劑顆粒大小（0.710, 0.500, 0.350 and 0.210 mm）及金屬濃度（5, 10, 50, 100 and 200 mg/l）與縮水甘油醚（Ethylene Glycol Diglycidyl Ether）之交聯條件下，單一金屬和多種金屬與生物吸附劑之間的競爭吸附關係，進而建立其吸附模式及確立其吸附機制。最後，進行固定床管柱實驗建立流動吸附之基礎實驗數據，並進行實驗室模廠之透水性反應牆試驗，以了解其穿透過程中吸附去除之效率，從而建立現地解決地下水中重金屬污染之復育整治技術。
Because of the dramatic develop of industry, heavy metal pollution has become a global environmental considerations. The heavy metals in the soil and groundwater have endangered our environment and human body by direct or indirect pathway. Thus, how to solve efficiently the heavy metal pollution in groundwater has become the most essential issue around the world. Theoretically, the strategy for groundwater remediation cloud be divided in two categories, “control” and “treatment”. The treatment methods for groundwater contaminated site cloud be divided in two technologies, including the “ex-situ” and “in-situ” remediation. The most widely application based on the idea of in-situ remediation in US is permeable reactive barrier, due to its economical efficiency in treating large contamination area, and was widely accepted as an efficiency technology for groundwater remediation. This research is based on the ideal of green design and the concept of biodegradable material coated with clays, which is a two years research for the feasibility study of heavy metal adsorbed by chitosan immobilized on bentonite. In batch study, this research will focus on the comparative adsorption of Cd2+, Ni2+, Pb2+ and Zn2+ in aqueous medium using a synthesized bioadsorbents. Composite beads will be successfully prepared by simple stirring and heat mediated blending of chitosan with bentonite at giving ratio. The adsorption study will be set at 25 ºC, and 50 rpm sharking rate. The competition adsorption model will be investigated based on various experimental parameters including various pH values, different particle sizes (0.710, 0.500, 0.350 and 0.210 mm), initial metal concentrations (5, 10, 50, 100 and 200 mg/l), adsorbent loading, and crosslinking with EGDE (Ethylene Glycol Diglycidyl Ether). Finally, the lab scale of permeable reactive barrier will be designed and established, in order to provide the experimental data of continuous adsorption study to evaluate the uptake efficacies. Thus, this research can achieve the object of in-situ remediation of heavy metal contaminations in groundwater. |
