电沉积NiHCF薄膜在碱土金属溶液中的电控离子分离性能

采用电沉积方法在铂基体上制备出电活性NiHCF(Nickel Hexacyanoferrate)薄膜,在碱土金属溶液中考察了薄膜电极对碱土金属离子的电控离子分离性能.通过循环伏安法在0.1mol·L-1Mg(NO3)2、Ca(NO3)2、Sr(NO3)2和Ba(NO3)2溶液中可逆置入和释放碱土金属离子,比较了不同溶液中NiHCF膜电极的电活性、电化学行为和离子的置入机制;在0.1mol·L-1Mg(NO3)z Ba(NO3)2]混合溶液中结合电化学石英晶体微天平(EQCM)原位检测了不同浓度下膜电极氧化还原过程中的伏安特性曲线和频率响应,分析了薄膜对Mg/Ba离子的选择性;并通过XPS测定了氧化还原状态下NiHCF膜的化学组成及元素价态.结果表明,NiHCF膜在二价碱土金属溶液中具有可逆的离子交换行为,对Ba2 离子的选择性大于Mg2 离子,通过电控离子分离方法可以实现碱土金属离子的有效分离.

Electrochemically Controlled Ion Separation Performances of Electrodeposited Nickel Hexacyanoferrate Thin Films in Alkaline Earth Metal Solution

Nickel hexacyanoferrate (NiHCF) thin films were synthesized on platinum substrates by cathodic deposition and the film-electrode systems were investigated as electrochemically controlled ion separation (ECIS) materials for the selective separation of alkaline earth ions in aqueous nitrate solutions. In 0.1 mol·L^-1 Mg(NO₃)₂, Ca(NO₃)₂, Sr(NO₃)₂ and Ba(NO₃)₂ solutions, cyclic voltammetry (CV) was used to reversibly intercalate and deintercalate alkaline earth cations from the matrix and to investigate the electroactivity, electrochemical behavior and the loading mechanism of NiHCF film electrodes. CV and electrochemical quartz crystal microbalance (EQCM) were used to investigate the ion selectivity of the films in 0.1 mol·L^-1 Mg(NO₃)₂+Ba(NO₃)₂] mixture solution. The chemical composition and elemental valence of NiHCF films in reduced and oxidized form were also characterized by X-ray photoelectron spectroscopy (XPS). Experimental results show that the cathodically deposited NiHCF film electrodes have reversible electrochemical behavior in alkaline earth metal solution and display a high Ba²⁺ selectivity in Mg^2+/Ba²⁺ mixtures. The alkaline earth metal ions can be separated effectively by ECIS processes.