高铁酸钠的电化学合成及铁阳极钝化机理研究  

Electrochemical synthesis of sodium ferrate(Ⅵ)and passivation mechanism of the ferrous anode

作　　者：杨雪 曾亚南 李俊国 刘宝 YANG Xue;ZENG Ya’nan;LI Junguo;LIU Bao(College of Metallurgy and Energy,North China University of Science and Technology,Tangshan 063210,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210

出　　处：《工业水处理》2022年第10期125-131,138,共8页Industrial Water Treatment

基　　金：河北省自然科学基金高端钢铁冶金联合基金项目(E2021209043);河北省高等学校科学技术研究项目(BJ2021034)。

摘　　要：以铁片为阳极、金属钛板为阴极,采用电化学氧化法合成高铁酸钠,研究了NaOH电解液浓度、制备温度和电流密度对高铁酸钠生成的影响及机理,并探析了高铁酸钠制备过程中铁阳极钝化的机理。结果表明,提高NaOH浓度和制备温度不仅有利于高铁酸钠的生成,同时也有利于提高电流效率;提高电流密度虽会增加高铁酸钠的生成量,但也会显著降低电流效率。综合考虑电流效率和制备成本,高铁酸钠的最佳制备条件为:NaOH浓度为14 mol/L、温度为45℃、电流密度为5 mA/cm^(2)。在最佳制备参数下电解后,利用FESEM-EDS和XPS分析了铁电极的表面性质,长时间电解后的铁阳极表面生成了铁氧化物,且钝化后的铁阳极表面存在Fe^(2+)和Fe^(3+)。电化学氧化合成高铁酸钠过程中,铁阳极钝化生成Fe_(3)O_(4)是阳极失效的主要原因。Sodium ferrate(Ⅵ)was synthetized using electrochemical oxidation with ferrous plate as anode and metal titanium plate as cathode.The influence of NaOH concentration,preparation temperature and current density on the generation of sodium ferrate(Ⅵ)was explored.The passivation mechanism of the ferrous anode was also investigated The obtained results indicated that increasing NaOH concentration and preparation temperature not only beneficial to the generation of sodium ferrate(Ⅵ),but also beneficial to improve the current efficiency.Although enhancing current density improved the generated concentration of sodium ferrate(Ⅵ),the current efficiency significantly reduced Considering the current efficiency and production costs,NaOH concentration of 14 mol/L,preparation temperature of45℃,current density of 5 mA/cm^(2)was regard as the best parameter for the synthesis of sodium ferrate(Ⅵ).Under the optimum preparation parameters,the surface properties of ferrous electrode were analyzed by FESEM-EDS and XPS The results showed that iron oxides were formed on the surface of the ferrous anode after passivation,and Fe^(2+) and Fe^(3+) existed on the surface of the ferrous anode after passivation.The generation of Fe_(3)O_(4) during the electrochemical oxidation process was the main reason for the passivation of ferrous anode.

关 键 词：电化学合成 高铁酸钠 阳极 钝化 

分 类 号：TQ035[化学工程] O614.81[理学—无机化学]