零價鐵處理土壤中多環芳香碳氫化合物之可行性研究

由於含碳氫化合物不完全燃燒之沉降，或石化燃料使用及輸送過程洩漏，導致土壤及地下水之多環芳香碳氫化合物(PAHs)汙染，嚴重影響生態環境。PAHs已被證實超過30種及好幾百種衍生物具有治癌性，為目前所知環境中最大量具有致癌性單一化學物種，並已被聯合國管制為持久性有機汙染物之一。近年來，已有愈來愈多國內外成功案例以零價鐵應用於現地污染場址之整治復育。本研究目的為加入微米零價鐵(＜10μm)，處理汙染土壤中含單或數種PAHs，以模擬實場汙染，並藉由參數改變如PAHs初濃度改變與添加鐵量等評估批次處理之可行性。實驗中選用台灣南投名間大埔美系紅壤（未含PAHs），土中添加之目標汙染物為三苯環之phenanthrene及四苯環之pyrene。土壤樣品以超音波萃取並以高效能液相層析儀(HPLC)定量分析。由結果得知初濃度改變對於單獨三環或四環PAHs之回收率影響較小，其個別回收率達到87±4%與81±4%。當加入0.05g零價鐵(＜10μm)後，土中平均phe.與pyr.知去除率各別約94%與52%；二者混合狀態下，去除率隨期初濃度增加而降低，故可知零價鐵可有效去除PAHs，其初濃度亦會影響去除效率。

關鍵字

零價鐵；多環芳香烴化合物； phenanthrene ； pyrene ；持久性有機汙染物

並列摘要

Polycyclic aromatic hydrocarbons PAHs in soil and groundwater primarily result from the settling of uncompleted combustion in air and petroleum fuel usage, transportation and leaks so that seriously damaged ecological environment. There are more than 30 PAHs and hundreds of their derivations are proved to be carcinogenic, moreover, they are listed in one of the 16 persistent organic pollutants (POPs) by United Nations Economic Commission for Europe (UN/ECE). In this decade, zero-valent iron (ZVI) has applied successfully in the site remediation. Thus, the objective of this study was to propose iron to the soil contaminated with PAHs of various initial concentrations. The operational parameters consisted of iron dosage and concentrations of PAHs. In the study, the Tapumei soil series in Nantou, Taiwan and the three-rings of phenanthrene (phe., C_(14)H_(10)) and four-rings of pyrene (pyr., C_(16)H_(10)), as the target compounds were employed. Meanwhile, the soil samples were extracted by sonication and identified the concentrations by high performance liquid chromatography (HPLC). The experimental results showed that the recovery efficiencies of mixed PAHs of phe. and pyr. in soil samples especially decreased for phe., neither changed for pyr.. The significant treatment efficiencies were observed while adding 0.05g iron in 15 minutes under various initial concentrations. Therefore, the ZVI can efficiently remove the target compounds in soil samples.