FABRICATION AND MODIFICATION OF POLYACRYLONITRILE MEMBRANES FOR ORGANIC SOLVENT NANOFILTRATION

Abstract

Organic solvents are ubiquitous and play important roles ranging from chemical syntheses to industrial cleaning. Organic solvent nanofiltration (OSN), a membrane-based separation technique, stands out as a promising method for the recovery and reuse of organic solvents. Towards this end, this thesis explores the fabrication, cross-linking and modification of several polyacrylonitrile (PAN) based membranes in both the hollow fiber and flat sheet configurations for use in OSN. Firstly, ultrafiltration PAN hollow fibers with a sponge-like morphology and minimal macrovoids were fabricated by adjusting the dope composition and spinning conditions. Then, they were cross-linked to yield nanofiltration membranes with improved solvent resistance. Next, the hollow fibers were further modified in a one-step process using the naturally-occurring plant biophenol, tannic acid, for improved performance. To study other materials, Zn(BDC) metal-organic framework and tungsten (IV) disulfide were incorporated atop modified PAN flat sheet substrates. In all cases, viable OSN membranes were successfully fabricated.