An electrochemically switchable triiodide-ion-imprinted PPy membrane for highly selective recognition and continuous extraction of iodide

Abstract

An electrochemically switchable triiodide-ion-imprinted polypyrrole (PPy/I3−) membrane composed of uniform bowl-shape particles with an interconnected ant-nest-like structure was successfully developed for the highly selective recognition and continuous extraction of iodide from the aqueous solutions in a novel electrochemically switched ion membrane extraction (ESIME) process. As a result, the PPy/I3− membrane with the ESIME process displayed a high I− ion flux of 2.87 × 10−4 g·cm−2·h−1, high separation factors of 3.44, 3.98, 5.02 and 5.27 for I− over Br−, Cl−, SO42− and PO43− anions, respectively, and excellent cycling stability with an extraction efficiency of 94.8% even after 10-cycle reuse at the optimized conditions with a cell voltage of 1.8 V, a pulse potential of −0.8 V/+0.95 V, a pulse width of 20 s. It is expected that the PPy/I3− membrane with ESIME process could be a promising candidate for the continuous, efficient and eco-friendly extraction of target I− from industrial water system.