A Novel Porous Ni, Ce-Doped PbO2 Electrode for Efficient Treatment of Chloride Ion in Wastewater

Abstract

The porous Ti/Sb-SnO2/Ni-Ce-PbO2 electrode was prepared by using a porous Ti plate as a substrate, an Sb-doped SnO2 as an intermediate, and a PbO2 doped with Ni and Ce as an active layer. The surface morphology and crystal structure of the electrode were characterized by scanning electron microscope(SEM), energy dispersive spectrometer(EDS), and X-Ray diffraction(XRD). The electrochemical performance of the electrodes was tested by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and electrode life test. The results show that the novel porous Ni-Ce-PbO2 electrodes with larger active surface area have better electrochemical activity and longer electrode life than porous undoped PbO2 electrodes and flat Ni-Ce-PbO2 electrodes. In this work, the removal of Cl− in simulated wastewater on three electrodes was also studied. The results show that the removal effect of the porous Ni-Ce-PbO2 electrode is obviously better than the other two electrodes, and the removal rate is 87.4%, while the removal rates of the other two electrodes were 72.90% and 80.20%, respectively. In addition, the mechanism of electrochemical dechlorinating was also studied. With the progress of electrolysis, we find that the increase of OH- inhibits the degradation of Cl−, however, the porous Ni-Ce-PbO2 electrode can effectively improve the removal of Cl−.

Editorial on Special Issue Electrolysis Processes

“…With respect to water, one issue is water scarcity, causing 1.2 billion people to suffer from a lack of water [7]. Another issue is industry or domestic-based water pollution [7][8][9]. Due to the widespread use of chlorinated compounds such as HCl, NaCl, and MgCl 2 in the industry, the content of chloride ion in wastewater is increasing [8,9].…”

“…Another issue is industry or domestic-based water pollution [7][8][9]. Due to the widespread use of chlorinated compounds such as HCl, NaCl, and MgCl 2 in the industry, the content of chloride ion in wastewater is increasing [8,9]. If it is discharged directly to the environment, diverse environmental issues will be created with consequences for water resources, soil and human health.…”

“…Electrochemical oxidation processes have a high potential for efficient removal of even trace amounts of Cl − due to high degradation efficiency, no secondary pollution, modularity, flexibility, and use of renewable electricity, which can contribute to stabilization of the energy grid. The degradation efficiency and degradation products of the electrochemical oxidation process change with the anode material, therefore, two articles by Xu et al [8] and Liu et al [9] discuss the development of new anode materials for electrochemical Cl − removal. Xu et al [8] studied porous Ti/SnO 2 -Sb 2 O 3 /PbO 2 electrodes for electrocatalytic oxidation of chloride ions by varying different parameters.…”

“…The advanced electrode structure minimized oxygen evolution as a side reaction, which further increased the removal effect of chloride ions. In the further publication, Liu et al [9] studied different material combinations. The porous Ti/Sb-SnO 2 /Ni-Ce-PbO 2 electrode was prepared by using a porous Ti plate as a substrate, an Sb-doped SnO 2 as an intermediate, and a PbO 2 doped with Ni and Ce as an active layer.…”

Removal of Cl(−I) from acidic industrial wastewater through oxidation: a review on methods and mechanisms

“…Naturally, the electrolysis approach, where the redox reactions can easily occur under the function of a current, was studied for the oxidation removal of Cl(−I) in the form of Cl 2 gas in the past few decades. [48][49][50][51] Although various Cl(−I)-removal methods have been studied and proposed, the common disadvantage of low efficiency in these approaches makes it necessary to develop new Cl(−I)-removal methods with higher efficiency. In addition, the limitations of different Cl(−I)-removal technologies, for instance, the high dosage of precipitants in the precipitation method, the high regeneration frequency of ion exchangers in the ion exchange method, and the demand of the low Cl(−I) concentration in the physical separation method, also show the importance of further research studies on Cl(−I) removal from wastewater.…”