Electrically and Electrochemically Assisted Nanofiltration: A Promising Approach for Fouling Mitigation

Abstract

Membrane fouling is regarded as the most critical bottleneck for the widespread application of membrane separation technology. The application of electricity to the surface of membrane provides a promising alternative for fouling mitigation, which may involve the following effects such as electrophoresis, electroosmosis, and electrooxidation. Electrophoresis and electroosmosis influence the movement of charged species (ions or molecules) or movement of fluid adjacent to charged surface under the applied electric field, while electrooxidation functions by degrading species accumulated in the concentration polarization layer and fouling layer to resume permeate flux. Different membrane modules have been developed to satisfy the requirement of electrode assembly. Meanwhile, this coupled process also promotes the development of stable and conductive electrodes including membrane electrodes. Successful applications have been found in the areas of ion separation and treatment of dye wastewater, arsenic contaminated wastewater, antibiotic contaminated wastewater, etc. Compared with microfiltration (MF) and ultrafiltration (UF), existing research in the nanofiltration (NF) is still limited. The increasing applications of NF in practice because of its unique separation capability will definitely trigger more investigations on this electrically or electrochemically combined antifouling technique.

A Comprehensive Review of Electrochemical Membrane Bioreactors for Enhanced Pollutant Removal and Fouling Mitigation

“…Electroosmosis offers another effective method for membrane fouling mitigation by removing bound water from sludge flocs through the application of an electric field. This process induces migration of water molecules towards the cathode, reducing interaction forces between water molecules and sludge particles, resulting in drier sludge and reduced fouling (Ping & Guohua, 2018). Research on an AnOMEBR demonstrated a 26% reduction in the concentration of soluble microbial products and enhanced electrostatic repulsion between the charged membrane surface and foulants, leading to significantly lower cake layer thickness compared to conventional AnMBRs (Xu et al, 2020).…”