Electric Field-Assisted Nanofiltration for PFOA Removal with Exceptional Flux, Selectivity, and Destruction.
Yangyuan JiYoun-Jeong ChoiYuhang FangHoang Son PhamAlliyan Tan NouLinda S LeeJunfeng NiuDavid M WarsingerPublished in: Environmental science & technology (2023)
Per- and polyfluoroalkyl substances (PFAS) pose significant environmental and human health risks and thus require solutions for their removal and destruction. However, PFAS cannot be destroyed by widely used removal processes like nanofiltration (NF). A few scarcely implemented advanced oxidation processes can degrade PFAS. In this study, we apply an electric field to a membrane system by placing a nanofiltration membrane between reactive electrodes in a crossflow configuration. The performance of perfluorooctanoic acid (PFOA) rejection, water flux, and energy consumption were evaluated. The reactive and robust SnO 2 -Sb porous anode was created via a sintering and sol-gel process. The characterization and analysis techniques included field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), ion chromatography, mass spectroscopy, porosimeter, and pH meter. The PFOA rejection increased from 45% (0 V) to 97% (30 V) when the electric field and filtration were in the same direction, while rejection capabilities worsened in opposite directions. With saline solutions (1 mM Na 2 SO 4 ) present, the induced electro-oxidation process could effectively mineralize PFOA, although this led to unstable removal and water fluxes. The design achieved an exceptional performance in the nonsaline feed of 97% PFOA rejection and water flux of 68.4 L/m 2 hr while requiring only 7.31 × 10 -5 kWh/m 3 /order of electrical energy. The approach's success is attributed to the proximity of the electrodes and membrane, which causes a stronger electric field, weakened concentration polarization, and reduced mass transfer distances of PFOA near the membrane. The proposed electric field-assisted nanofiltration design provides a practical membrane separation method for PFAS removal from water.
Keyphrases
- electron microscopy
- high resolution
- reduced graphene oxide
- endothelial cells
- solid state
- single molecule
- mass spectrometry
- signaling pathway
- hydrogen peroxide
- high speed
- high glucose
- liquid chromatography
- magnetic resonance
- inflammatory response
- diabetic rats
- computed tomography
- oxidative stress
- nitric oxide
- carbon nanotubes
- magnetic resonance imaging
- pi k akt
- tandem mass spectrometry
- dual energy
- hyaluronic acid
- human health