Managing colloidal fouling of nanofiltration membranes: Facile control of colloid-membrane interactions in polyelectrolyte multilayer(PEM)-based membrane systems
- Graduate student: Wenqian Shan (Environmental Engineering, MSU)
- Primary Adviser: Dr. Volodymyr Tarabara (Environmental Engineering, MSU)
- PERMEANT collaboration: Dr. Patrice Bacchin and Dr. Martine Meireles (UPS, Toulouse)
Because of the minimum in particle backtransport for colloids of ca. 100 nm in diameter, particles of this size have the highest membrane fouling potential. Enhancing backtransport via specific membrane-colloid interactions is a viable approach to the mitigation of fouling by these colloids. Deposition of three polyelectrolytes – poly(allylamine hydrochloride), poly(styrenesulfonic acid), and poly(diallyldimethylammonium chloride) with different salt concentration and in different sequences on 50kDa ultrafiltration membrane was employed to prepare PEM membranes with a range of hydrophilicities and surface charges. Fouling resistance of the PEM membranes was tested by challenging them with suspensions of silica oxide (negatively charged) and aluminum oxide (positively charged) colloids. It was demonstrated that a significant reduction in flux decline could be achieved by a judicious choice of the PEM membrane for a given colloidal foulant. Poly(diallyldimethylammonium chloride)-based PEMs, known to be regenerable by simple changing the pH of deposition, were demonstrated to retain this property even after significant fouling by colloids.