Work

Evaluating a new ultra-thin dense-skin hollow Fiber membrane for vacuum membrane distillation

Year: 2025

Type: article

Abstract: Membrane distillation (MD) utilizes microporous membranes to support a liquid-vapor interface and can be used for desalination. Polyvinylidene fluoride (PVDF) based membranes show high permeate fluxes, however they are prone to pore wetting and per - and polyfluoroalkyl substances (PFAS) release, thus motivating the search for new MD membranes. This study evaluates, as an alternative membrane for vacuum MD (VMD), a new hollow fiber (HF) composite membrane with an ultra-thin dense layer of polydimethylsulfone (PDMS) coated on the external surface of a polysulfone (PSU) microporous HF, with potentially low wettability and higher fluxes than completely dense fibers. The so-called Fiber B was compared with a microporous PVDF HF ( Fiber A ) for outside/in VMD operation, based on their morphology, Knudsen permeability, wettability/wetting, and thermal aging. The permeate flux and the driving force vary linearly for Fiber B , indicating that it behaves as a VMD membrane, despite its dense layer. Subsequently, Fiber B showed a higher permeability than Fiber A and similar to that of a commercial HF implemented in industry. Short-term wetting tests confirmed that Fiber B avoids pore wetting with saline solutions, while Fiber A showed partial wetting. Fiber B showed stronger mechanical properties and thermal aging induced less severe changes to its permeability, surface, and structural properties , due to the choice of its materials. The new composite fiber has the potential to be a greener alternative to fluorinated-based HFs for VMD, with competitive permeability while avoiding wetting. Its longer-term thermal and wetting stabilities remain to be verified before industrialization.

Source: Separation and Purification Technology

DOI: 10.1016/j.seppur.2025.136026

Authors: Indira Chimanlal, Cécile Formosa-Dague, Maria Iliopoulou, Despina Fragouli, Corinne Cabassud

Institutions: Centre National de la Recherche Scientifique, Institut National des Sciences Appliquées de Toulouse, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Université de Toulouse, Italian Institute of Technology

Language: English

Topic: Membrane Separation Technologies

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,060

Funders: European Commission, HORIZON EUROPE Framework Programme, H2020 Marie Skłodowska-Curie Actions