biostudies-literatureUnknown12(2)Zoka LThe effects of flipping membranes with hydrophilic/hydrophobic asymmetry are well documented in the literature, but not much is known on the impact of flipping a membrane with dense/porous layer asymmetry. In this work, the pure water flux (PWF) of a commercial polyethersulfone (PES) membrane and a ceramic ultrafiltration (UF) membrane was measured in the normal and inverted positions. Our experimental results showed that the PWF was two orders of magnitude higher when the PES membrane was flipped to the inverted position, while the increase was only two times for the ceramic membrane. The filtration experiments were also carried out using solutions of bovine serum albumin and poly(vinylpyrrolidone). A mathematical model was further developed to explain the PWF increase in the inverted posMembranes129https://www.ebi.ac.uk/biostudies/studies/S-EPMC8874773biostudies-literatureFlux Increase Occurring When an Ultrafiltration Membrane Is Flipped from a Normal to an Inverted Position-Experiments and Theory.PMC8874773Matsuura TZoka LIsmail AFKhoo YSNarbaitz RLau WJfalseFlux Increase Occurring When an Ultrafiltration Membrane Is Flipped from a Normal to an Inverted Position-Experiments and Theory.The effects of flipping membranes with hydrophilic/hydrophobic asymmetry are well documented in the literature, but not much is known on the impact of flipping a membrane with dense/porous layer asymmetry. In this work, the pure water flux (PWF) of a commercial polyethersulfone (PES) membrane and a ceramic ultrafiltration (UF) membrane was measured in the normal and inverted positions. Our experimental results showed that the PWF was two orders of magnitude higher when the PES membrane was flipped to the inverted position, while the increase was only two times for the ceramic membrane. The filtration experiments were also carried out using solutions of bovine serum albumin and poly(vinylpyrrolidone). A mathematical model was further developed to explain the PWF increase in the inverted pos2022-01-01T00:00:00Z2022 Jan2025-04-27T01:03:35.077Z2025-04-06T18:05:43.853ZS-EPMC88747733520705410.3390/membranes12020129