Electrospun carbon nanofibers as microfiltration membrane for removal of humic acid and polystyrene particles

• Main Author: Tang, Ming Xue.
• Other Authors: Sun Delai, Darren
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/53831
• Institution: Nanyang Technological University

This project explores the feasibility of developing carbon nanofiber membrane as pre-filters through the process of electrospinning and subsequent thermal treatments, due to their excellent chemical and thermal resistance, high wettability, interconnected open pore structure, large surface area per unit volume, consistency of fibers diameter in submicron range and cost effectiveness of the fabrication process. In this study, polyacrylonitrile (PAN) nanofibers were electrospun into membrane and further treated through the process of stabilization and carbonization to enhance the mechanical properties of the membrane as well as making it thermally stable. The morphologies and structures of the carbon nanofiber (CNF) membrane were investigated by field emission scanning electron microscopy (FESEM) while the pore size and the BET surface area were determined using the capillary flow porometer. CNF membranes and cellulose acetate (CA) membrane (CA) were put to test in the filtration of humic acid at 5 & 10ppm. In the humic acid experiment, CNF and CA membranes have yield a separation factor in the range of 40% for both humic acid of 5 and 10 ppm with the CNF showing a slightly higher separation factor in both test. In another experiment, CNF membranes were used to separate 0.0458, 0.202, 0.465 and 2.061 μm polystyrene (PS) particles. The membrane had a bubble point pore size of 0.7905 μm and was able to remove above 99% of 2.061 μm particles without occurrence of permanent fouling, and yields an average separation factor of 63%, 22% and 4% for particles size of 0.465, 0.202 and 0.0458 μm respectively. Attributes and characteristics of the CNF membrane have resulted in yielding ultra-high flux along with desirable separation factor. This study has demonstrated the potential of CNF membrane being applied as pre-filters as well as in microfiltration process for the removal of particulates and contaminants such as humic acid. In addition, the possibility of regenerating the CNF membrane via heat treatment was also studied in this project to showcase the thermal stability and exploit this unique characteristic of the CNF membrane. However, more studies with a wider range of heating temperature would have to be done in the future as there were no substantial results yielded from the existing experiment.