Electrified membranes for microplastic fouling mitigation

The excessive use of plastics has created a route for microplastics into our water and wastewater treatment plants. Coupled with the on-going water crises, this creates a threat to fresh water availability as microplastics disrupt the operation of these plants. Microplastics result in severe fouling to low pressure membrane technologies, such as ultrafiltration. Electrified membranes are suggested as an alternative microplastic fouling mitigation strategy. In this study, polyethersulfone (PES) pellets were sulfonated to create sulfonated polyethersulfone (SPES), resulting in an additional layer of negative charge for microplastic repulsion. PES and SPES membranes were then fabricated using non-solvent induced phase inversion, and tested under DC electric field as a fouling mitigation strategy. Additionally, several characterization techniques were utilized to confirm the sulfonation and study the morphology and structure of the fabricated membranes. These include Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray diffraction (XRD), Raman Spectroscopy, and Fourier Transform Infrared Spectroscopy (FTIR). Finally, the microplastic flux, pore characteristics, hydrophilicity and charge of the fabricated membranes were determined experimentally. The microplastic flux increased by 16% in SPES compared to PES at 0 V. Additionally, the microplastic flux increased from 22.7 ± 0.9 L/m2.h in PES at 0 V to 34.0 ± 0.9 L/m2.h in SPES at 5 V, which reflects a 49% increase. This study lays basic foundations for this system as a microplastic fouling mitigation strategy, and creates a route for future studies on suitable membrane materials to enhance the system.