Chlorine-Resistant Reverse-Osmosis Membrane

Physical Sciences : Materials and Compounds

Available for licensing

Inventors

  • Benny Freeman, Ph.D. , Chemical Engineering
  • Ho Park, Ph.D. , Hangang University
  • James McGrath, Ph.D. , Virginia Polytechnic Institute and State University

Background/unmet need

Current state-of-the-art technology for reverse osmosis filtration of water has one major flaw: the addition of chlorine can cause the membrane to degrade. However, when treating saltwater or brackish water, it is necessary to introduce chlorine for sanitation and disinfection purposes. Unfortunately, commercially available membranes encounter significant problems when chlorine is introduced: namely, the degradation of the membrane, followed by the severe reduction of the permeability of the membrane and salt rejection rates.

Invention Description

This invention satisfies the need for a chlorine-tolerant reverse osmosis membrane that can control membrane biofouling and eliminate the dechlorination steps involved at desalination plants. A chlorine-tolerant reverse osmosis membrane allows for higher feed pressure (i.e., higher flux) without biofouling, as the flux no longer has to be restricted to low feed pressure to prevent flux from being greater than a critical value beyond which biofouling occurs. The existing commercial thin-film composite membranes have high water flux and salt rejection, but lack chemical stability to oxidants (e.g., chlorine), have a high fouling rate due to surface roughness, and undergo biofouling due to a strong bacteria affinity.

The current invention is a polymeric membrane that can withstand the addition of chlorine into water purification systems such as reverse osmosis (desalination) and nano-filtration. This new membrane can accommodate chlorine, while having minimal effect on membrane flux and salt rejection rates. It is effective in filtering oily waters and water containing components such as algae, organic contaminants, and harmful trace metals like arsenic.

Benefits/Advantages

  • Simple manufacturing process
  • Highly reproducible technique
  • Increased efficiency
  • Cost-effective
  • Versatile
  • Outperforms commercially available membranes

Features

  • Chlorine resistant
  • High desalinization rates
  • Excellent permeability
  • Structural versatility
  • Excellent mechanical properties

Market potential/applications

The U.S. water filtration market is a multi-billion dollar industry. Due to its superior properties, this membrane has the potential to become the new standard for reverse osmosis filtration.

Development Stage

Lab/bench prototype

IP Status