结晶
阴极
电化学
降水
化学工程
阴极保护
碱度
材料科学
化学
电极
物理
工程类
物理化学
气象学
有机化学
作者
Qianyuan Yang,Longqian Xu,Qiang He,Deli Wu
出处
期刊:Water Research
[Elsevier]
日期:2022-02-01
卷期号:209: 117893-117893
被引量:13
标识
DOI:10.1016/j.watres.2021.117893
摘要
Electrochemical precipitation is a promising technique for hardness abatement without the addition of external ions. However, the scale layer on cathode deteriorated the removal efficiency and limited the practical application. Herein, a fenced cathode structure was designed to prevent cathodic precipitation. The cathode was fenced by a crystallization-inducing material for separating the OH- production and crystallization processes. Precipitation on the cathode was confirmed to shift to the crystallization-inducing material, and the clean fenced cathode provided efficient long-term OH- production. At a current density of 40 A/m2, the Ca2+ or Mg2+ removal efficiency increased by 12.8% or 46.1%, respectively, compared to those of a traditional cathode. Thermodynamic equilibrium in synthetic water and mine water, mass transfer and the location of precipitation were analyzed to elucidate the electrochemical precipitation process. The enhanced mechanism was ascribed to the crystallization-inducing material, which remarkably promoted the crystallization process, and hindered OH- migration, thereby increased the pH of alkaline microenvironment. Notably, a recovery design was proposed to recover pure calcite and brucite from alkalinity-free wastewater. The design reveals a promising strategy for enhancing the crystallization process and reducing cathodic scale, also initiating a new research direction toward hardness removal.
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