Choi Jeongyun, Batchelor Bill
Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-Dong, Yuseong-Gu, Daejeon 305-701, Republic of Korea.
Chemosphere. 2008 Jan;70(6):1108-16. doi: 10.1016/j.chemosphere.2007.07.053. Epub 2007 Sep 14.
Nitrate reduction by the fluoride form of green rust modified with copper (GR-F(Cu)) was investigated using a batch reactor system. The extent of nitrate reduction was measured by measuring the increase in concentration of ammonia, which is the final product of nitrate reduction by GR. This approach was required, because nitrate could be removed from solution by ion exchange without reduction. The rate of ammonium production was investigated over the range of pH 7.8-11. The fastest reaction was achieved at pH 9 when GR was present at a concentration of 0.083M as Fe(II) and 1mM of Cu(II) was added. The rate at pH 9 was enhanced by a factor of 2.5 compared to that at pH 7.8 by comparing the time elapsed to transform all nitrate to ammonium. Kinetics of nitrate reduction by GR-F at pH 7.8 were affected by the concentration of Cu(II) added. The rate constants for ammonium production increased from 0.012 to 1.52h(-1) as Cu(II) additions increased from 0 to 2.5mM, but the reaction rate at 5mM was slightly decreased to 1.25h(-1). The mechanism of enhanced rates of nitrate reduction by addition of Cu(II) could not be fully determined in this study. However, XRD results showed that magnetite was produced in the reaction of Cu(II) and GR-F and SEM shows the production of nano-size particles which were not fully identified in this study. In addition, the concentration of Fe(II) in GR was observed to linearly decrease with concentration of Cu(II) added.
使用间歇式反应器系统研究了铜改性的氟化物形式的绿锈（GR-F(Cu)）对硝酸盐的还原作用。通过测量氨浓度的增加来测定硝酸盐还原的程度，氨是GR还原硝酸盐的最终产物。之所以需要这种方法，是因为硝酸盐可以通过离子交换从溶液中去除而不发生还原。在pH 7.8 - 11范围内研究了铵的生成速率。当GR以0.083M的Fe(II)浓度存在并添加1mM的Cu(II)时，在pH 9时实现了最快的反应。通过比较将所有硝酸盐转化为铵所经过的时间，pH 9时的反应速率比pH 7.8时提高了2.5倍。pH 7.8时GR-F还原硝酸盐的动力学受添加的Cu(II)浓度影响。随着Cu(II)添加量从０增加到2.5mM，铵生成的速率常数从0.012增加到1.52h⁻¹，但5mM时的反应速率略有下降至1.25h⁻¹。本研究中无法完全确定添加Cu(II)提高硝酸盐还原速率的机制。然而，XRD结果表明在Cu(II)与GR-F的反应中生成了磁铁矿，SEM显示生成了纳米尺寸的颗粒，本研究中未对其进行完全鉴定。此外，观察到GR中Fe(II)的浓度随添加的Cu(II)浓度呈线性下降。
