THE USE OF ANIONIC SURFACTANTS FOR REDUCING FOULING OF ULTRAFILTRATION MEMBRANES - THEIR EFFECTS AND OPTIMIZATION

Pretreatments with anionic surfactants and their applications have been studied for the reduction of fouling during ultrafiltration of proteins. Surfactant chemistry and the composition of mixed surfactants were systematically varied. The initial pure water fluxes were reduced, but the ultrafiltration fluxes were usually enhanced, and flux decline due to fouling reduced. In contrast to the long nonionic surfactants studied previously, the small anionic surfactant (AOT) appears to provide a different means of reducing protein deposition by altering the electrostatic interactions between the protein and membrane surface. When used in conjunction with nonionic surfactants or when polyethylene oxide segments are added to their backbone, the anionic surfactants showed significant flux improvement and fouling resistance compared with that of the single AOT or the nonionic surfactant. The effectiveness of the pretreatment is sensitive to pH and protein charge.