Electrochemical behavior of aluminium anode in super-gravity field and its application in copper removal from wastewater by electrocoagulation.
Electrochemical behavior of aluminium anode in super-gravity field and its application in copper removal from wastewater by electrocoagulation.
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DOI：
10.1016/j.chemosphere.2021.129614
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发表时间：
2021-01
期刊：
影响因子：
8.8
通讯作者：
Yu Yu-Yu;Yiwei Zhong;Mingyong Wang;Zhancheng Guo
中科院分区：
文献类型：
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作者：
Yu Yu-Yu;Yiwei Zhong;Mingyong Wang;Zhancheng Guo
阳极钝化是降低电凝（EC）工艺效率的关键问题。将超重力技术引入EC工艺，强化纯铝电极对重金属废水的处理。结果表明，随着重力系数的增大，Cu去除率升高，槽电压降低，说明超重力场对电絮凝过程有促进作用。采用动电位极化、循环伏安法和电化学阻抗谱分析了超重力场下铝阳极的电化学行为。研究发现，铝的阳极极化行为表现出典型的超重力溶解特征，而不是正常重力下的钝化特征。阳极溶解类型由点蚀转变为超重力场均匀腐蚀。阳极外层氧化膜变薄，阳极溶解释放出更多的Al3+离子，这归因于Cl−离子传质过程的超重力增强。此外，X射线衍射和傅里叶变换红外光谱表明，超重力场中生成的絮体具有非晶态且较松散的Al-O骨架结构。结果，超重力提高了EC过程的效率。
Anodic passivation is a key problem to reduce the efficiency of electrocoagulation (EC) process. Super-gravity technology was introduced into EC process to enhance the treatment of heavy metal wastewater using pure aluminum electrode. The results showed that the removal ratio of Cu increased, and the cell voltage decreased with the increase of gravity coefficient, suggesting a promoting effect of super-gravity field on electrocoagulation process. Electrochemical behavior of aluminium anode in super-gravity field was analyzed by potentiodynamic polarization, cyclic voltammetry and electrochemical impedance spectroscopy. It was found that anodic polarization behavior of aluminium showed a typical characteristic of dissolution in super-gravity, rather than passivation in normal gravity. The type of anode dissolution changed from pitting corrosion to uniform corrosion in super-gravity field. The outer oxidized film of anode was thinning, and more Al3+ions were released by anode dissolution, which was attributed to the super-gravity enhancement of the mass transfer process of Cl−ions. In addition, X-ray diffraction and Fourier transform infrared spectroscopy indicated that the flocs generated in super-gravity field had amorphous and looser Al–O framework structure. As a result, the efficiency of EC process was improved by super-gravity.