Advanced Thin Film Composite and Nanocomposite Polyamide Membrane for Water Treatment

• Author / Creator

  Khorshidi Mianaee, Behnam

• Membrane technology is currently widely used for separation of ions, colloids, organic matter and macromolecules. Among various membrane processes, nanofiltration (NF) and reverse osmosis (RO) with thin film nanocomposite (TFC) polyamide (PA) membrane at the heart of the separation process is being increasingly employed for sea and brackish water treatment and wastewater reclamation. Over the past decade, the increasing need to implement highly cost and energy efficient membranes processes has accelerated the research effort to fabricate advanced composite membranes with enhanced permeation, thermomechanical, and antifouling properties. In the present research, systematic studies were conducted to fabricate high performance composite PA membrane with improved thermal stability and antifouling propensity. First, the effects of synthesis conditions and chemical additives were studied on the permeation properties of the TFC PA membranes. The composite membranes were prepared by interfacial polymerization (IP) reaction between meta-phenylene diamine (MPD)-aqueous and trimesoyl chloride (TMC)-organic solvents (such as heptane, hexane and cyclohexane) at the surface of polyethersulfone (PES) microporous support. Several influential factors including the concentration of the reacting monomers, reaction time and temperature, thermal curing temperature, and the concentration of chemical additive such as surfactant, pH regulator, co-solvents in the water-based monomer solution was investigated using design of experiment (DOE) methodology. The results revealed that the final permselectivity of a TFC PA membrane is remarkably dependent of its surface physicochemical properties, structural characteristics and the complex internal free volumes which can all be influenced by synthesis conditions. The findings of the first stage of this research provided valuable insight and useful guidelines for the development of TFC PA membranes with wide range of water permeation and salt rejection. These findings were used in the second stage of the research where robust and high performance nanocomposite membranes were prepared by incorporation of metal oxide nanoparticles (NPs) to the membrane structure. Initially, nanocomposite microporous membranes were prepared by integration of indium tin oxide (ITO) NPs to the PES matrix via phase inversion process. The resulting PES-ITO membranes demonstrated higher thermal stability and antifouling porosity comparted to pristine PES membranes when tested with industrially produced water. Finally, titanium dioxide (TiO2) NPs were effectively incorporated to the PA active layer using a combination of biphasic solvothermal (BST) reaction and IP reaction. The resulting thin film nanocomposite (TFN) PA-TiO2 membranes showed an enhanced thermal stability and anti-biofouling characteristics compared to base TFC PA membranes.

• Subjects / Keywords

  • Metal oxide nanoparticle
  • Polyamide Membrane
  • Reverse osmosis
  • Interfacial polymerization reaction
  • Thin film composite
  • Thin film nanocomposite
  • Nanofiltration

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3F766P8W

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.