256912 Quarternized Chitosan Electrospun Membranes for Virus Removal

Thursday, November 1, 2012: 12:30 PM
408 (Convention Center )
Caryn L. Heldt and Bingyu Bai, Chemical Engineering, Michigan Technological University, Houghton, MI

For remote or personal water systems, small pore size membranes can be added to reject bacteria and viruses from water purely based on size; but, the small pore size required to remove these pathogens often increases membrane fouling and leads to large membrane areas, high transmembrane pressures, low water flux,  and frequent changing of membranes.  This increases the cost of water filtration.  In order to make clean water accessible to everyone, there is an urgent need for improved water disinfection technology.  Our goal is to create functionalized, large pore-sized membranes that have the ability to absorb virus and bacteria.  Membranes with pores on the order of microns have the advantage of increased flow rate and reduced membrane fouling.  As a first step in our goal to create water filtration membranes, we have created membranes made of biocompatible, inexpensive, and environmentally friendly chitosan, which has the ability to be functionalized to increase the membrane disinfection capacity.  Nanofiber, chitosan membranes have been made by electrospinning.  These membranes have an increased surface area as compared to microfibers and are on the same size scale as viruses, creating a curved surface that has the potential to improve virus absorption.  Chitosan membranes were originally made, but the virus adsorption capability was low.  To improve the virus absorption, we functionalized the membranes with a quaternized amine, forming a  N-[(2-hydroxy-3- trimethylammonium) propyl] chitosan chloride (HTCC) blend.  The HTCC cationic polymer has an increased positive charge, as compared to chitosan, and therefore, has increased virus absorption capability.  Additives have been used to increase the ability to electrospin HTCC, by changing the viscosity and conductivity of the electrospinning solution.  HTCC membranes have the ability to remove greater than 99% of virus present in solution, completing the first step to the creation of adsorption membranes that can remove pathogens from water.

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