摘要：

以Si/BDD（Boron-doped diamond）、Ti/SnO₂、Ti/PbO₂、Ti/Pt 4种常见电极为阳极，考察其在电解Na₂SO₄生成过硫酸盐（PDS）过程中的电化学行为，以及低电流密度条件下电解质浓度，电流密度和PDS、H₂SO₄、NH₄SCN的投加对电解法制备PDS的影响。结果表明：在低电流密度条件下，生成PDS的主要途径是通过阳极电解水产生·OH来介导SO₄ ^2-的氧化；相同反应条件下，4种阳极中Si/BDD阳极电解体系对PDS的生成效果最佳，以Si/BDD电极为阳极，在Na₂SO₄浓度0.9 mol/L、电流密度60 mA/cm²条件下，电解60 min时生成的PDS浓度为24.12 mmol/L；提高电解质浓度和电流密度可以提高电流效率和PDS产量，向电解质中添加Na₂S₂O₈和NH₄SCN可以减少析氧副反应发生，添加H₂SO₄可以降低反应所需槽电压；经正交实验分析，各反应条件对电解生成PDS的显著性影响由高到低依次为电流密度、Na₂SO₄浓度、Na₂S₂O₈投加浓度。

关键词: 阳极, 过硫酸盐, 电解, 制备

Abstract:

Using four common electrodes including Si/BDD（Boron-doped diamond），Ti/SnO₂，Ti/PbO₂ and Ti/Pt as anodes，the electrochemical behavior of electrodes in the process of producing persulfate （PDS） by electrolysis of Na₂SO₄ was investigated. The effects of electrolyte concentration，current density and the addition of PDS，H₂SO₄ and NH₄SCN at low current density on the preparation of PDS by electrolysis were also researched. The results showed that，under the condition of low current density，the main way to generate PDS was ·OH produced by electrolyzing water mediated the oxidation of SO₄ ^2-. Under the same reaction conditions，Si/BDD anode had the best effect on PDS formation among the four kinds of anodes. Under the conditions of 0.9 mol/L of Na₂SO₄ concentration， 60 mA/cm² of current density，the PDS yield reached 24.12 mmol/L after 60 min with Si/BDD electrode as the anode. Increasing electrolyte concentration and current density could improve current efficiency and PDS production. The addition of Na₂S₂O₈ and NH₄SCN to the electrolyte reduced the occurrence of oxygen evolution side reactions and the addition of H₂SO₄ reduced the cell voltage required for the reaction. According to the orthogonal experiment analysis， the dominance of each reaction condition on the electrolysis-generated PDS followed current density，Na₂SO₄ concentration and Na₂S₂O₈ dosing concentration.

Key words: anode, persulfate, electrolysis, preparation

中图分类号: 

• X703.1

• TQ118