DENSE HYDROPHILIC COMPOSITE MEMBRANES FOR ULTRAFILTRATION

Dense hydrophilic composite membranes for ultrafiltration were prepare d from an asymmetric porous PVDF support coated with a thin (< 1 mu m) layer of polyether-block-polyamide copolymer. Membranes with a molecu lar weight cut-off between 800 and 4500 g/mol and water permeability b etween 2.3 and 9.4 1 h(-1) m(-2) bar(-1) were obtained. The dry membra ne surface was characterized as a dense non-porous layer when observed by scanning electron microscopy. When compared to other commercial me mbranes and to the non-coated porous PVDF support in the ultrafiltrati on of oil-water waste, the performance of the composite membranes was comparable to the Amicon YM30 cellulose membrane with lower susceptibi lity to fouling.