A multifunctional and low-energy electrochemical membrane system for chemical-free regulation of solution pH. (1st June 2022)

• Record Type: Journal Article
• Authors: Long, Wei; She, Qianhong
• Is Part Of: Water research. Volume 216(2022)
• Publication Date: 2022-06-01
• Subjects: electrochemical membrane system -- pH adjustment -- electrochemical reactions -- chemical-free -- low energy consumption; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.118330
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: A chemical-free electrochemical membrane system (EMS) was developed for solution pH regulation. EMS was equipped with simple and cost-effective membrane cell configuration. EMS filtration mode enabled simultaneous membrane filtration and pH control. EMS for pH regulation only consumed extremely low energy. Abstract: A proper pH environment is essential for a wide variety of industries and applications especially related to water treatment. Current methods for pH adjustment including addition of acid/base and electrochemical processes demonstrate disadvantages associated with environment and energy. Here, we designed a multifunctional electrochemical membrane system (EMS) with one piece of filtration membrane inserted into an electrochemical cell. When electrical field was applied, OH − and H + ions were produced from reduction and oxidation reactions at cathode and anode, respectively. The membrane posed a resistance for the transport of OH − and H + ions and prevented their mixing in the cell. The EMS can be also operated in a filtration mode, which could simultaneously regulate permeate and feed pH and accomplish water filtration. In both non-filtration and filtration modes, EMS could achieve effective control of solution pH over a wide range by exerting different voltages without dosing any chemicals. Under the voltage of 1.2 V, the solution pH could reach and be maintained at 10.7 and 3.3 in cathodic and anodic channels, respectively. Furthermore, it was experimentally demonstrated that the EMS only consumed extremely low energy. This, together with membrane filtration in an integrated manner, highlights the huge potential of the EMS for applications in various water industries. Graphical Abstract: Graphical Abstract Image, graphical abstract .