Development of hydrophilic polyamide imide microfiltration/ultrafiltration membranes for oil sands produced water treatment

• Author / Creator

  Helali,Nusrat

• Endless growth of petrochemical, metallurgical, and food industries has resulted in massive water pollution caused by oily materials. Membrane separation processes is one of the fastest emerging technologies for oily wastewater treatment due to their distinct advantages over traditional processes, primarily lower compact design and high product quality. However, fouling of membranes by the adhesion of oil onto the membrane surface and inside its’ pores is a major challenge for effective treatment of oily wastewater. We used a novel hydrophilic polymer, polyamide-imide (PAI), to make hydrophilic and underwater superoleophobic microfiltration membranes via non-solvent induced phase separation technique. In the first work, we modified the membranes with hydrophilic additives, including polyethylene glycol (PEG, 0.4 and 6 kDa) and polyvinylpyrrolidone (PVP, 10 and 360 kDa) to improve their hydrophilicity further via blending approach. Oil rejection experiments were conducted to evaluate the reusability of the synthesized membranes. The use of additives resulted in a wide range of membrane morphology, porosity, pore size, and surface chemical property, which affected the permeation rate and flux recovery. However, all synthesized membranes showed >98% rejection of oil. The optimized membranes had underwater superoleophobic property (OCA>150°) and showed almost 98% pure water flux recovery ratio. This study proposes a facile approach of making superhydrophilic and underwater superoleophobic membranes.
  In the second work, we applied a facile layer by layer (LbL) assembly approach for improving the hydrophilicity and selectivity of base PAI membranes using water soluble polyelectrolytes: polydiallyldimethylammonium chloride and polyacrylic acid. The pure water flux declined dramatically with increasing number of coated layers. The antifouling property of the modified membranes against humic type organic foulants in oil sands produced water was investigated. Pristine PAI membrane showed 62% rejection of organic matters, while the rejection increased up to 65% with the deposition of four bilayers. Simultaneously, the permeate flux decline improved by 26%. All the membranes showed 100% water flux recovery, which shows excellent antifouling property of PAI membranes. This study proposes that due to the presence of inherent hydrophilic functional group on PAI polymer, PAI membranes can be efficiently used as a substrate for LbL deposition. The number of bilayers can be further increased to obtain targeted selectivity and antifouling property.

• Subjects / Keywords

  • Oil sands produced water
  • Microfiltration membrane
  • Ultrafiltration membrane

• Graduation date

  Spring 2020

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-ccrw-s522

• License

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