Under-brine superaerophobic perfluorinated ion exchange membrane with re-entrant superficial microstructures for high energy efficiency of NaCl aqueous solution electrolysis

Abstract

Perfluorinated ion exchange membrane (PIEM) with excellent anti-bubble property is of great significance for high energy efficiency of electrolysis of NaCl aqueous solution (chlor-alkali process). Here, an under-brine superaerophobic perfluorinated ion exchange membrane (SPIEM) with ZrO2 coating is successfully achieved by a facile and efficient spray method. The ZrO2 coating with hierarchical micro/nanoscale surface structure endows the membrane a low bubble adhesive force of 72.81 μN and ultrahigh bubble contact angle of 151.3° in brine solution. The superaerophobic property of the membrane is favorable for reducing bubbles adhesion, maximizing the effective working area of the membrane and promoting ion transport. By employing SPIEM as ion exchange membrane, the electrolysis cell of NaCl aqueous solution shows a low power consumption of 1923 kWh t−1 and it can save about 100 kWh and 90 kWh of power for producing per ton of NaOH than using PIEM (2030 kWh t−1) and Nafion ™ N2030 (2010 kWh t−1) at 4.5 kA m−2. It is believed that this study is beneficial for development of high performance chlor-alkali ion exchange membrane and provides a perspective for other polymer electrolyte membranes.