Electrified Membranes for Water Treatment Applications

Abstract

Electrified membranes (EMs) have the potential to address inherent limitations of conventional membrane technologies. Recent studies have demonstrated that EMs exhibit enhanced functions beyond separation. Electrification could enhance the performance and sustainability of membrane technologies and stimulate new applications in water and wastewater treatment. Herein, we first describe EM materials, synthesis methods, electrofiltration modules, and operating modes. Next, we highlight applications of EMs in water decontamination, purification, and disinfection. Additionally, we discuss state-of-the-art electrification methods for controlling membrane organic fouling, biofouling, and inorganic scaling. We also evaluate the energy consumption of EMs for water treatment and fouling control. We conclude by discussing the challenges for improving the stability and practicality of EMs and by proposing pathways for future research and development. On the basis of our discussion, we suggest that EMs may be viable for ultrafiltration and microfiltration but not for salt-rejecting reverse osmosis and nanofiltration applications. Further, we find that EMs are promising for decontamination and organic fouling control, and these systems could be deployed for fit-for-purpose distributed treatment applications.

Methods for stability assessment of electrically conductive membranes

“…ECMs have presented several advantages as compared to conventional membranes such as: (a) controllably target foulants at the membrane/water interface which makes them more effective than traditional bulk solution cleaning (biocide dosing, pH adjustment) [15] , [16] , [17] , (b) use electrons, “clean reagents”, as antifouling mediators, making the process less chemical intense and easy to operate, which reduces the handling and storage costs of chemicals [18] , [19] , [20] , and (c) can tailor their antifouling mechanisms by tuning the applied electrical properties (polarity, magnitude, and frequency). Therefore, the antifouling mechanisms can be tailored to exclusively match the application [ 7 , 17 , 21 ].…”

Recent advances in electrocatalytic membrane for the removal of micropollutants from water and wastewater

“…Statistical analysis ( Figure 5 D and Table 1 , Table 2 , Table 3 , Table 4 , Table 5 ) shows the median fluxes for different electrocatalytic membranes: 138.74 L/(m 2 ·h) for carbon-based membranes, 1916.5 L/(m 2 ·h) for porous-Ti-based membranes, 195 L/(m 2 ·h) for magnéli-phase-based membranes, 138.9 L/(m 2 ·h) for electrochemical ceramic membranes, and 64 L/(m 2 ·h) for polymer composite membranes. A high membrane flux can facilitate mass transfer and enhance the removal efficiency of micropollutants ( Sun et al., 2021 ). However, if the membrane flux is over high, the contact time between the organic compounds and the strong oxidizing species will be too short to degrade the micropollutants, resulting in a decrease of the removal efficiency ( Guo et al., 2016 ; Trellu et al., 2018b ).…”

A Review on Promising Membrane Technology Approaches for Heavy Metal Removal from Water and Wastewater to Solve Water Crisis

“…It should be noted that the system also makes use of an upstream EM. EM reaction mechanisms (dashed line boxes) and schematics (dotted circles) (B) Nitro-organic compound (e.g., 4-nitrophenol and NDMA) and (C) heavy metal (e.g., Cr 6+ ) mediated reduction [162].…”