Article pubs.acs.org/IECR
Novel Nanofiltration Hollow Fiber Membrane Produced via Electrospinning Fadwa Hussein Anka and Kenneth J. Balkus, Jr.* Department of Chemistry, The University of Texas at Dallas, 800 West Campbell Rd., Richardson, Texas 75080-3021, United States ABSTRACT: Submicrometer polyacrylonitrile (PAN) hollow fiber membranes were fabricated via concentric electrospinning and were assembled into a filtration module. The module operated in an “inside-out” mode where a feed solution is introduced through the lumen while filtrate is collected from outside the fiber wall through a side arm. The relatively smooth PAN fibers exhibited 530 and 890 nm average inner and outer diameters, respectively. The performance of the hollow fibers was tested by filtering an Indigo carmine dye and NaCl solutions. The dye solution passed through the PAN fibers, and the filtrate was colorless indicating that water but not dye permeates through the fiber walls. In a similar fashion, the NaCl solution was desalinated with 97.7% ± 0.6 salt rejection.
1. INTRODUCTION Polymeric hollow fiber membranes have been widely used in different types of separations such as gas separations, water filtration, pervaporation, and dialysis due to their large surface area-to-volume ratio and their ease of handling as selfsupporting membranes.1,2 Hollow fiber membranes used for water filtration or desalination are usually produced by melt spinning, wet spinning, dry spinning, or dry− wet spinning techniques. These techniques generate hollow fibers that are several hundred micrometers in diameter. Also, these methods involve bulky expensive equipment that require space and maintenance that adds to the overall processing cost, possibly limiting their use in developing countries. As a result, hollow fiber membrane filtration modules that are efficient, affordable, portable, and easy to fabricate would be an advance. Electrospinning is an easy low-cost benchtop method used to produce nanofibers that have high surface area per unit volume.3−7 Typically, a high voltage is applied to a polymer solution, resulting in a polymer jet ejected toward a grounded collector as the electrostatic forces overcome the surface tension. The polymer jet dries on the way to the collector where nanofibers are deposited. Electrospun polymeric hollow fibers have been reported in the literature.8−12 Most of these reports involve the orientation of these hollow fibers and their biocompatibility for the purpose of using them in enzyme immobilization and medical applications such as tissue engineering or nerve regeneration.3,12 Concentric electrospinning can be used to prepare hollow fibers that can range from a few micrometers to nanofibers (
