阴离子交换膜修饰的水/1,2-二氯乙烷界面上SO42-离子的转移反应

将一种均相季铵型阴离子交换膜用于修饰水/1,2-二氯乙烷(W/DCE)界面,并利用循环伏安法、差分脉冲伏安法和计时电量法考察了该界面上强亲水性阴离子SO₄^2-的转移反应过程.研究结果表明,该阴离子交换膜所修饰的W/DCE界面比修饰前具有更宽的电化学窗口,而且在界面上可获得完整的SO₄^2-转移的循环伏安曲线和差分脉冲伏安曲线.其中,循环伏安曲线的峰电流与扫速平方根呈线性关系,SO₄^2-在膜内水相中的扩散系数为7.6×10^-8 cm²/s;差分脉冲伏安曲线的峰电流与SO₄^2-的浓度在5~25 mmol/L范围内呈线性关系.另外,利用计时电量法测得SO₄^2-在该界面上转移反应的标准速率常数为1.49×10^-3 cm/s.

Ion-transfer Reaction of SO42-Across the Water/1,2-dichloroethane Interface Modified by an Anion Exchange Membrane

In this work, the anion-transfer reaction of highly hydrophilic sulfate across the water/1,2-dichloroethane(W/DCE) interface modified by a homogeneous anion exchange membrane(AEM) was investigated by employing cyclic voltammetry(CV), differential pulse voltammetry(DPV) and chronocoulometry. It was found that the electrochemical window could be extended by the modification of W/DCE interface with such an AEM. In addition, the well-defined CV and DPV curves corresponding to the ion-transfer of highly hydrophilic SO₄^2- could be obtained at the modified W/DCE interface. According to the linear relationship between the peak current of CV and the square root of scan rate, as well as the equation of Randles-Sevik, the diffusion coefficient of SO₄^2- in the membrane containing water is calculated to be about 7.6×10^-8 cm²/s. In addition, the peak current of DPV increases linearly with the concentration of SO₄^2-within the range of 5-25 mmol/L. Moreover, the standard reaction rate constant of the ion-transfer of SO₄^2- at such an AEM-modified W/DCE interface was estimated to be about 1.49×10^-3 cm/s via chronocoulometry.