College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, PR China; Faculty of Environmental Science and Technology, Kunming University of Science and Technology, Kunming, 650500, PR China.
Department of Geography and Tourism Management, Chuxiong Normal University, Chuxiong, 675000, PR China.
Chemosphere. 2020 Jul;250:126225. doi: 10.1016/j.chemosphere.2020.126225. Epub 2020 Feb 19.
For the purification of heavy metal wastewater, internal micro-electrolysis (IME) was considered as an effective method but some disadvantage greatly restricts its application. Electrocatalytic internal micro-electrolysis (ECIME) fluidized bed using iron-carbon particles was proposed to avoid disadvantaging of IME. The principal aim of this study was to investigate the enhanced removal characteristics, mechanism, and kinetic behavior of Cu(II) that none clear before. ECIME reactor shows a better copper removal performance and depends much on the polarization of the external electric field (EEF). Both the reaction rate and removal efficiency of copper electrodeposition improved obviously. Noteworthy is more than 88.0% of Cu(II) in aqueous solutions was removed by enhanced electrodeposition, and only about 10.0% of Cu(II) was absorbed and flocculated through the in situ formed iron hydroxyl compounds. Through scanning electron microscopy (SEM) and electrochemical analysis, copper can effectively electrodeposition on the surface of iron-carbon particles in ECIME reactor and accordingly the enhanced mechanisms were proposed. 1) Iron-carbon particles of ECIME formation of microelectrodes with high surface potential, larger specific area, and active sites through electrode collision and repolarization. 2) Copper electrodeposition on the formed microelectrodes exhibited greater reduction peak potential, reaction overpotential and exchange current density, which influenced by the polarization voltage significantly. 3) The electrocatalytic environment tend to in situ generate iron polymer hydroxyl compounds help to further remove residual Cu(II). ECIME fluidized-bed has promised potential for heavy metal containing wastewater purification and metal recovery. In addition, the proposed reaction models will be useful for field application.
为了净化重金属废水，内部微电解（IME）被认为是一种有效的方法，但一些缺点极大地限制了它的应用。本研究提出了用电催化内部微电解（ECIME）流化床来避免 IME 的缺点。这项研究的主要目的是研究增强去除 Cu(II)的特性、机制和动力学行为，因为之前对此并不清楚。ECIME 反应器表现出更好的铜去除性能，并且很大程度上取决于外部电场（EEF）的极化。铜电沉积的反应速率和去除效率都明显提高。值得注意的是，水溶液中超过 88.0%的 Cu(II)通过增强电沉积去除，只有约 10.0%的 Cu(II)通过原位形成的铁羟基化合物的吸收和絮凝去除。通过扫描电子显微镜（SEM）和电化学分析，铜可以有效地在 ECIME 反应器中的铁-碳颗粒表面上进行电沉积，从而提出了增强机制。1）ECIME 形成的铁-碳颗粒通过电极碰撞和再极化形成具有高表面电势、更大比表面积和更多活性位点的微电极。2）铜在形成的微电极上的电沉积表现出更大的还原峰电位、反应过电位和交换电流密度，这受到极化电压的显著影响。3）电催化环境倾向于原位生成铁聚合物羟基化合物，有助于进一步去除残留的 Cu(II)。ECIME 流化床有望用于净化含重金属废水和金属回收。此外，所提出的反应模型将有助于现场应用。
