Development of Electrospun MembranesBased on PVDF-HFP Modified by Nanosized Zeolite

  • Haya Nassrullah

Student thesis: Master's Thesis

Abstract

Current methods to treat wastewater like produced water and refinery effluents before discharging are unable to keep up with the ever increasing stringent regulations of discharge and reuse. Membrane distillation (MD) is an emerging membrane technology that can be used to overcome this challenge. MD is particularly attractive because it can remove oil and salt from such wastewaters in one step, producing freshwater. However, pore clogging and wetting by low surface tension contaminants limit the use of MD for oily wastewater treatment. To overcome this challenge, a dual-layered membrane, consisting of an underwater superoleophobic top layer of electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) coated with regenerated cellulose (RC) and a hydrophobic bottom layer of electrospun PVDF-HFP was developed before [1]. The membrane was successful in desalinating oily wastewater through direct contact membrane distillation (DCMD). While the membrane maintained complete salt and oil rejection in DCMD, its permeate flux was relatively low. In this work, the performance of the dual-layered membrane in terms of permeate flux was enhanced by incorporating different concentrations of Linde type L (LTL) zeolite nanoparticles into the top membrane layer via cellulose surface coating. The results showed that the MD performance was optimized when 1 wt% of nanoparticles was embedded in the cellulose coating. The composite membrane with 1 wt% zeolite loading maintained a flux 38% higher than that of the dual-layered membrane without zeolite in oily saline water desalination. This is attributed to the increase in top layer porosity from 41.59% to 49.71% induced by the addition of 1 wt% of LTL nanoparticles. The results from this study suggest that the incorporation of LTL zeolite nanoparticles into the cellulose coating can effectively enhance the membrane performance without compromising the oil and salt rejection in DCMD.
Date of AwardDec 2019
Original languageAmerican English

Keywords

  • Membrane Distillation
  • Underwater Superoleophobicity
  • Nanozeolites
  • Dual-layered.

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