Polyvinylamine/Amino acid Salt Membranes for CO2 Separation

A novel method for synthesizing polyvinylamine/amino acid salt membranes with increased stability, CO2 permeance, and CO2 selectivity

The Need

Facilitated transport membranes utilize fixed carriers, such as Polyvinylamine (PVAm), and mobile carriers to provide high CO2 permeance and maintain a high CO2/N2 selectivity compared to solution-diffusion membranes. Current production methods of commercial PVAm introduce many problems that can diminish the membrane's stability, CO2 permeance, and selectivity. The process typically involves a hydrolysis step that uses sodium hydroxide (NaOH), which inadvertently produces by-products (i.e., sodium formate salt) within the polymer product that can damage the stability of the membrane. The PVAm that is produced by this process also has a low molecular weight, which lowers the viscosity of the coating solution. Lower viscosity causes membrane penetration, which increases mass transfer resistance and decreases CO2 permeance. To meet the growing need for CO2 separation and capture, facilitated transport membranes that produce enhanced stability, increased CO2 permeance and CO2 selectivity must be developed.

The Technology

Researchers at The Ohio State University, led by Dr. Winston Ho, have developed a novel method to synthesize PVAm membranes with amino acid salts as mobile carriers for CO2 separation applications.The viscous PVAm/mobile carrier coating solution is knife-coated onto different substrates to form a thin selective layer of the membranes synthesized.

Commercial Applications

  • Gas separation
  • Power plants

Benefits/ Advantages

  • Higher CO2 permeance for CO2 capture from flue gas in power plants
  • Reduced pollution
  • This method does not produce non-reactive salts as a by-product, which improves the stability of the membrane
  • Stronger polymer matrix and greater viscosity due to the high molecular weight of the synthesized PVAm
  • Increased strength improves the stability of the membrane and allows more carriers to be incorporated into the polymer solution to further improve transport performance

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