Development of micro-scale hollow fiber ultrafiltration membranes

This work describes the development of micro-scale hollow fibers (HF) ultrafiltration membrane module using asymmetric microtubes produced by the co-electrospinning technique. Poly(caprolactone) (PCL) microtubes of average inner diameter of 4 μm with wall thickness of 0.9 μm and poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) with average inner diameter of 1.4 μm, wall thickness of 0.9 μm have been successfully achieved. The retention of the water soluble polymer poly(acrylic acid-co-maleic acid), sodium salt (50 kDa) (PAA) (as a model contaminant) was used to evaluate the performance of HF modules. Applying pressure of up to 3.5 bars to the HF modules of PCL and PVDF-HFP of 5.4 cm in length have shown typical flux of 30–60 L/m2 h, typical rejection of 25–35% and 28–40% correspondingly, and typical recovery of 20–37%. These results show a great potential in the use of micro-scale HF membranes for water purification.