黄腐酸和湖泊孔隙水对Fe(Ⅱ)还原Cr(Ⅵ)为Cr(Ⅲ)的影响

Reduction of Cr(Ⅵ) to Cr(Ⅲ) by Fe(Ⅱ) in the Presence of Fulvic Acids and in Lacustrine Pore Water

考查了缺氧条件下Fe(Ⅱ)-有机质(DOM)的络合物将Cr(Ⅵ)还原为Cr(Ⅲ)的还原能力。研究发现在没有或有萨旺尼河黄腐酸(SRFA)和波尼湖黄腐酸(PLFA)存在的情况下,Fe(Ⅱ)都能够将Cr(Ⅵ)快速地还原(几分钟)。Fe(Ⅱ)-DOM溶液不一定比仅含有Fe(Ⅱ)单一的体系具有更强的还原力。DOM的组成也影响了Cr(Ⅲ)的还原机制,湿地(俄亥俄州老妇人河河口区)沉积物进行缺氧萃取得到的沉积物孔隙水能够将Cr(Ⅵ)更快地还原。这些研究数据表明自然界中富含Fe(Ⅱ)和DOM的缺氧孔隙水对Cr(Ⅵ)的非生物还原反应速率远大于生物还原反应速率,并且这一非生物还原反应是自然环境中Cr(Ⅵ)被还原的主要途径。

In this study, the efficiency of Fe(II)-dissolved organic matter (DOM) complexes to reduce Cr(VI) to Cr(III), under anoxic conditions was examined. Cr(VI) was quickly reduced (a few minutes) in Fe(II) solutions in the absence and presence of Suwannee River (SRFA) and Pony Lake fulvic acid (PLFA). Fe(II)-DOM solutions did not always reduce Cr(VI) faster than Fe(II)-only systems. DOM composition also influenced Cr(VI) reduction kinetics. Cr(VI) was reduced even more quickly in anoxically extracted sedimentary...