Dynamically formed poly (vinyl alcohol) ultrafiltration membranes with good anti-fouling characteristics

Abstract

The anti-fouling poly (vinyl alcohol) TFC membranes were dynamically prepared when an aqueous solution containing poly (vinyl alcohol), cross-linking agents and additives passed through porous substrate membranes under definite pressure followed by heat treatment resulting in cross-linking reaction and drying. By means of dead-end filtration the poly (vinyl alcohol) solution deposited on the surface and entered the pores of porous substrate and thus an even poly (vinyl alcohol) gel layer was formed on both the external and internal surface. The effects of poly (vinyl alcohol) concentration, dynamic coating time, additive concentration, cross-linking agent concentration, curing time and support membrane on pure water flux and protein rejection of the resultant membranes were studied. Membrane morphology was characterized by SEM studies. The modified membranes were investigated in ultrafiltration experiments with pepsin to assess their resistance to fouling. The experimental results prove that modified membranes with an even poly (vinyl alcohol) hydrogel layer show dramatically high anti-fouling characteristics compared to inadequately modified and unmodified membranes. Moreover, it is possible that a series of dynamic membranes within broader molecular weight cut-off can be readily obtained by suitable control and combination of various preparative conditions.