A New Approach to the Development of Hollow Fiber Membrane Modules for Water Treatment: Mixed Polymer Matrices

In this study, mixed matrix hollow fiber polymeric membranes were prepared using polyethersulfone (PES) and polyvinylidene fluoride (PVDF) as polymers in their composition. N-methyl-2-pyrrolidone (NMP) was used as a solvent and demineralized water with an electrical conductivity below 3 μS·cm^-1 was used as a non-solvent. A new approach to producing enhanced polymeric hollow fiber membranes based on the preparation of a simple blend PVDF/PES solution, and on the conformation of the composite membranes through the extrusion technique followed by the phase inversion process in a non-solvent bath, was applied. The investigation focused on the preparation of polymeric membranes with different polymer ratios and further assessment of the effects of these proportions on the membrane performance and in specific physical properties. The amount of PVDF ranged from 10 to 90% with 10% steps. The presence of PVDF, although it increased the membranes' plasticity, had a negative effect on the overall mechanical properties of the composite membranes. Scanning electron microscopy (SEM) results showed good dispersion of both polymers in the polymeric matrix. Furthermore, the membrane permeability showed a slight negative correlation with contact angle, suggesting that membrane hydrophilicity played an important role in membrane permeability. Finally, it was found that membranes with low ratios of PVDF/PES may have potential for water treatment applications, due to the combined advantageous properties of PES and PVDF.