Development of Novel Membranes Based on Electro–spun Nanofibers and Their Application in Liquid Filtration, Membrane Distillation and Membrane Adsorption

Abstract

Electro–spinning is known as a simple and versatile method to produce nonwoven membranes made out of nanofibers. A wide range of polymers and blends can be used to yield nanofibers. Commonly used membrane polymers such as cellulose acetate (CA), polysulfone (PSU) and polyvinylidene fluoride (PVDF) have been successfully electro–spun to form nonwoven nanofiber membranes for water filtration. Investigations have revealed that electro–spun nanofibrous membranes (ENMs) possess high–flux rates and low transmembrane pressure. These characteristics are due to its (1) high porosity, (2) interconnected open pore structure and (3) tailorable membrane thickness. Although electro–spun membranes have been extensively studied for decades and successfully commercialized as air filtration membrane, they have not been applied for water treatment. The nanofiber membranes were used recently at the Industrial Membrane Research Laboratory of the University of Ottawa with the collaboration of Nanoscience & Nanotechnology Initiative of the National University of Singapore for the following investigations.

1. Removal of latex particles from water: PVDF nanofiber membranes were subjected to filtration of latex particles (0.1 to 10 μm) at the feed pressure of 0.6 bar gauge [1, 2].
2. Seawater desalination by membrane distillation: PVDF nanofiber membranes were subjected to desalination of aqueous NaCl solutions by air gap membrane distillation [3, 4].
3. Trihalomethanes (THMs) and haloacetic acids (HAAs) removal by carbonized polyacrylnitrile (PAN) nanofiber membranes [5, 6].