采用阴极电沉积方法制备电活性NiHCF薄膜,考察薄膜在含Pb^2+溶液中的电控离子交换性能。在0.1mol/L的Pb(NO3)2溶液中,通过循环伏安法调节膜电极的氧化还原电位考察其活性和可逆性,并结合电化学石英晶体微天平(EQCM)技术分析离子的交换机制,同时比较Co(NO3)2和Ni(NO3)2溶液中NiHCF膜电极的电化学行为;在0.1mol/L[Pb(NO3)2+Co(NO3)2]和0.1mol/L[Pb(NO3)2+Ni(NO3)2]两组混合溶液中,通过循环伏安法分析薄膜对Pb^2+/Co^2+和Pb^2+/Ni^2+的选择性;并通过X射线能谱仪(EDS)分别测定膜在氧化和还原状态下的元素组成。结果表明,电活性NiHCF膜在含Pb^2+、Co^2+和Ni^2+溶液中均具有可逆的离子交换行为,对Pb^2+的选择性高于对Co^2+和Ni^2+的,通过电控离子交换方法可以使Pb^2+从废水中得到有效分离。
Electroactive nickel hexacyanoferrate(NiHCF) thin films were synthesized by cathodic deposition.The performance of electrochemically switched ion exchange(ESIX) of the NiHCF film for the separation of Pb^2+ from aqueous solutions was investigated.In 0.1 mol/L Pb(NO3)2 solution,cyclic voltammetry(CV) combined with electrochemical quartz crystal microbalance(EQCM) technique was used to investigate the electroactive,reversibility of the film electrodes and the mechanism of ion exchange.The electrochemical behavior of NiHCF film electrodes was also compared with that in Co(NO3)2 and Ni(NO3)2 solutions.The ion selectivity of the film was investigated in 0.1 mol/L mixture solution containing [Pb(NO3)2+Co(NO3)2] and [Pb(NO3)2+Ni(NO3)2],respectively.The elementary composition of NiHCF films in reduced and oxidized form were also characterized by energy dispersive X-ray spectroscopy(EDS).The results show that the electroactive NiHCF films have reversible electrochemical behavior in aqueous solutions containing Pb^2+,Co^2+ and Ni^2+,respectively.NiHCF film electrodes display a high Pb^2+ selectivity in both Pb^2+/Co^2+ and Pb^2+/Ni^2+ binary mixtures and Pb^2+ can be separated effectively from aqueous solutions by ESIX processes.