A novel electric-field-accelerated ion-sieve membrane (EISM) system with potential-oscillation was set up for the selective separation of the alkali metal ions. The ion-sieve membrane was fabricated by coating a polypyrrole/polystyrenesulfonate composite on the stainless steel wire mesh (PPy/PSS/SSWM). In the EISM system, an external electric filed was applied by introducing a constant cell voltage on the two sides of the ion-sieve membrane to accelerate the directed transport of target ions through the membrane. Meanwhile, an extra pulse potential was applied on the PPy/PSS/SSWM membrane to adjust the ion binding ability of the PPy/PSS composite toward cations. As such, an enhanced “ion sieving effect” of the EISM system was achieved through the synergistic function of the constant cell voltage and potential oscillation, which resulted in the rapid transport of target cation across the membrane in a “leap-frogging” way. It is found that when an extra pulse potential of ±1.0 V (pulse width of 60 s) was applied on the EISM, the permeation flux of K⁺ ions was increased by 7.42-fold with a constant cell voltage of 5 V. The permselectivities of the PPy/PSS/SSWM membrane for K⁺/Li⁺ and K⁺/Cs⁺ reached 3.29 and 3.45 respectively based on the optimized amplitude (±1.0 V) and frequency (pulse width of 60 s) of pulse potential.

建立了一种新型的带电势的电场加速离子筛膜（EISM）系统，用于碱金属离子的选择性分离。离子筛膜是通过在不锈钢丝网（PPy / PSS / SSWM）上涂覆聚吡咯/聚苯乙烯磺酸盐复合材料制成的。在EISM系统中，通过在离子筛膜的两侧引入恒定的电池电压来施加外部电场，以加速目标离子通过膜的定向传输。同时，在PPy / PSS / SSWM膜上施加了额外的脉冲电势，以调节PPy / PSS复合物对阳离子的离子结合能力。这样，通过恒定的电池电压和电势振荡的协同作用，实现了EISM系统增强的“离子筛分效果”，这导致目标阳离子以“跳跃式”方式跨膜快速运输。发现在EISM上施加±1.0 V的额外脉冲电势（脉冲宽度为60 s）时，K的渗透通量在5 V的恒定电池电压下，⁺离子增加了7.42倍。基于最佳振幅，PPy / PSS / SSWM膜对K ⁺ / Li ⁺和K ⁺ / Cs ⁺的选择性渗透率分别达到3.29和3.45（ ±1.0 V）和脉冲电位的频率（60 s的脉冲宽度）。