Electrochemical removal and recovery of phosphorus as struvite in an acidic environment using pure magnesium vs. the AZ31 magnesium alloy as the anode
Electrochemical removal and recovery of phosphorus as struvite in an acidic environment using pure magnesium vs. the AZ31 magnesium alloy as the anode
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DOI：
10.1016/j.cej.2019.122480
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发表时间：
2020-01-15
影响因子：
15.1
通讯作者：
Greenlee, Lauren F.
中科院分区：
文献类型：
--
作者：
Kekedy-Nagy, Laszlo;Teymouri, Ali;Greenlee, Lauren F.
研究了镁 (Mg) 电极作为单池电化学间歇反应器中阳极驱动鸟粪石沉淀的唯一镁来源。电池在酸性环境下运行，无需调节 pH 值。针对纯镁与 AZ31 镁合金，研究了电极成分对鸟粪石生产电池效率的影响。在 6 小时的批量实验中，纯镁阳极的性能优于 AZ31 合金，产生的鸟粪石质量高出 4.5 倍，稳态电流密度高出 2.8 倍。测得的纯Mg Mg 溶解速率为1.2 mg cm(-2) h(-1)，AZ31 镁合金阳极的Mg 溶解速率为0.8 mg cm(-2) h(-1)。通过 X 射线衍射、扫描电子显微镜、X 射线光电子能谱和能量色散 X 射线光谱分析了电化学沉淀鸟粪石的结构、形貌和成分。结果显示鸟粪石呈结晶状态，具有细长的针状形态，粒径约为。长30微米，约。宽度6.5μm。光滑锋利的边缘表明是高质量的纯鸟粪石，没有其他沉淀物或干扰阳离子的迹象。
Magnesium (Mg) electrodes were investigated as the only source of magnesium for anodically-driven struvite precipitation in a single-cell electrochemical batch reactor. The cell was operated in an acidic environment with no pH adjustment. The effect of electrode composition on cell efficiency toward struvite production was investigated for pure-Mg versus an AZ31 Mg alloy. In a 6 h batch experiment, the pure-Mg anode out-performed the AZ31 alloy by producing a 4.5-fold greater mass of struvite and a 2.8-fold higher steady-state current density. The measured Mg dissolution rates were 1.2 mg cm(-2) h(-1) for the pure-Mg and 0.8 mg cm(-2) h(-1) for the AZ31 Mg alloy anode, respectively. The structure, morphology, and composition of the electrochemically precipitated struvite were analyzed by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, and energy-dispersive x-ray spectroscopy. Results showed a crystalline struvite state, with an elongated needle-shaped morphology and a particle size of ca. 30 mu m in length and ca. 6.5 mu m in width. The smooth sharp edges are an indication of high-quality pure struvite, with no evidence of other precipitates or interfering cations.