水泥固化法配合化學改質活性碳以抑制污染土壤汞溶出之研究

汞在許多重金屬中是一大焦點，因其具有獨特的特性：高毒性、揮發性、在生物體中的累積性，因此汞已被確認為是一種有毒的世紀危害。無機汞及有機汞皆可嚴重的影響健康，有機汞的毒性比無機汞來得高，且生物體可把無機汞轉換為有機汞，因此控制汞污染廢棄物中的無機汞溶出是非常重要的。本研究利用水泥固化法配合化學改質活性碳來抑制土壤中汞的溶出，並分別比較養護7天及28天之TCLP溶出濃度，化學改質為溴化鈉改質活性碳及元素硫改質活性碳，原土未添加水泥及吸附劑之TCLP濃度為2.54×10-1 mg/L，超過我國法規標準(0.2 mg/L)。有添加吸附劑之固化試體皆可達到TCLP溶出標準，惟28天時濃度比7天高，可能之原因為pH值上升，造成固化試體內汞的再溶出，以及水灰比過低，造成汞在固化體內無法達到穩定狀態。因此後續研究建議應使pH值下降，以及適當的水灰比防止汞的再溶出。

關鍵字

固化/穩定化；汞；化學改質活性碳；毒性特性溶出程序(TCLP)

並列摘要

Mercury is receiving a major focal among many of the heavy metals due to its unique characteristics, such as its high toxicity, volatility and ability to bioaccumulate. Mercury has been recognized as a toxic hazard for centuries. Both inorganic and organic mercury can cause serious health effects. Organic forms of mercury are generally more toxic than inorganic forms, but it is possible for inorganic mercury to be biologically transformed into organic mercury. Therefore, it is important to control inorganic mercury leaching from mercury containing wastes. In this study, cement solidification accompanied with chemically modified activated carbon was used to inhibit the dissolution of mercury（Hg）from the contaminated soil. The research parameters for examining the leachability of Hg via the toxicity characteristic leaching procedure （TCLP）tests included the cement adding amount, the curing duration（seven days and 28 days）, the addition of chemically modified activated carbon (bromine and sulfur treated), and the water / cement ratio. The TCLP leaching concentration of Hg, for the original soil without added cement and carbon adsorbent was 2.54×10-1 mg / L, which exceeded Taiwan's regulation standard （i.e., 0.2 mg / L）. The leaching concentrations for soil samples after adding cement and carbon complied with the regulation standard, but 28 day curing caused a greater leaching concentration than 7 day curing. It may be explained that the increasing pH, after 28 day curing led to the enhancing dissolution of Hg from the contaminated soil. Additionally, the reducing water / cement ratio may also cause an increase in Hg leaching. Future approach in suppressing the release of Hg from contaminated soil should be focused on lower the pH and operating the solidification under ab appropriate water / cement ratio to avoid re-dissolution of Hg.

並列關鍵字

Solidification/ stabilization ； mercury ； chemically modified activated carbon ； toxicity characteristic leaching procedure (TCLP)

參考文獻

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水泥固化法配合化學改質活性碳以抑制污染土壤汞溶出之研究

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