零價鐵去除水中砷之研究

Arsenic Removal from Water by Zero-Valent Iron

巫昌逸(Chang-yi Wu)

指導教授 ： 羅煌木

朝陽科技大學/理工學院/環境工程與管理系/碩士(2011年)

摘要

本研究主要探討零價鐵對水中三價砷之去除效果。藉由批次瓶杯實驗探討不同環境條件下砷移除之反應動力學，環境條件包括pH值、攪拌速度、溫度和零價鐵量。實驗結果顯示在反應30 min時，pH值為7，溫度為25oC，轉速為150rpm，0.3 g 零價鐵對砷(III)初始濃度為1 mg L-1的去除率高達93.57 %以上，添加過量的零價鐵顆粒並不會依比例提升其移除效果。實驗結果顯示砷(III)與零價鐵顆粒的反應為假一階動力反應，其迴歸線之R2比假二階動力反應來得高。故反應較遵循假一階反應動力學方程，其標準化後的速率常數kSA 為16.23 mL m-2 min-1。研究結果顯示，在pH值偏中酸性，較高轉速（350 rpm）及常溫（25oC）的條件下，反應活性高的零價鐵可有效移除水中三價砷。

關鍵字

砷(III) ； 零價鐵 ； 去除率 ； 吸附 ； 一階反應動力學

並列摘要

This study investigated the efficiency of zero-valent iron (ZVI) on the removal of arsenite As(III) in groundwater. Batch experiments were conducted to examine the removal kinetics and the influence of pH, stirring speed, temperature and ZVI dosage. Removal was found higher than 93.57 % for 1 mg L-1 As(III) by 0.3g ZVI at 30 min, pH 7, 25oC, 150rpm. Results also showed that the removal of As(III) by ZVI was more likely to be pseudo first kinetics rather than pseudo second kinetics. The surface-area rate coefficient kSA was normalized to be 16.23 mL m-2 min-1. Experimental results showed that removal of As(III) had higher removal rate and R2 at acidic pH, higher stirring speed (350rpm) and room temperature (25oC). It is evident that ZVI had the potential to be a higher reactive material to remove the As(III).

並列關鍵字

Zero-valent iron (ZVI) ； As(III) ； Removal ratio ； Adsorption ； Pseudo first kinetics

參考文獻

王聖瑋，「台灣西南沿海地區地層環境中砷之來源與釋出機制」，碩士論文，國立臺灣大學生物環境系統工程學系，台北(2007)。

Alloway, B. J.,“Heavy Metals in Soils,” New York: Halsted Press, pp.106-121(1995).

Alowitz M. J. and Scherer M. M.,“Kinetics of nitrate, nitrite, and Cr(VI) reduction by iron metal,” Journal of Environmental Science &Technology, Vol. 36, No. 3, pp.299-306(2002).

Bang, S., Johnson, M. D., Korfiatis, G. P., and Meng, X., “Chemical Reactions between Arsenic and Zero-valent Iron in Water,” Journal of Water Research, Vol. 39, pp.763-770(2005).

Bang, S., Korfiatis, G. P., and Meng, X. G., “Removal of Arsenic from Water by Zero-Valent Iron,” Journal of Hazardous Materials, Vol. 121, Issue 1-3, pp. 61-67(2005).