Concentration polarization, nanophotonic flux enhancement and the mitigation of concentration polarization in pervaporation desalination
Description
Membrane based technology is one of the principal methods currently in widespread use to address the global water shortage. Pervaporation desalination is a membrane technology for water purification currently under investigation as a method for processing reverse osmosis concentrates or for stand-alone applications. Concentration polarization is a potential problem in any membrane separation. In desalination concentration polarization can lead to reduced water flux, increased propensity for membrane scaling, and decreased quality of the product water. Quantifying concentration polarization is important because reducing concentration polarization requires increased capital and operating costs in the form of feed spacers and high feed flow velocities. The prevalent methods for quantifying concentration polarization are based on the steady state thin film boundary layer theory. Baker’s method, previously used for pervaporation volatile organic compound separations but not desalination, was successfully applied to data from five previously published pervaporation desalination studies. Further investigation suggests that Baker’s method may not have wide applicability in desalination. Instead, the limitations of the steady state assumption were exposed. Additionally, preliminary results of nanophotonic enhancement of pervaporation membranes were found to produce significant flux enhancement. A novel theory on the mitigation of concentration polarization by the photothermal effect was discussed.
Date Created
The date the item was original created (prior to any relationship with the ASU Digital Repositories.)
2019
Agent
- Author (aut): Mann, Stewart, Ph.D
- Thesis advisor (ths): Lind, Mary Laura
- Committee member: Walker, Shane
- Committee member: Green, Matthew
- Committee member: Forzani, Erica
- Committee member: Emady, Heather
- Publisher (pbl): Arizona State University