NSF NEWT ERC Researchers Perform In-situ Fouling Monitoring and Removal Using Electrified Membrane Systems
Outcome/Accomplishment
Researchers with the National Science Foundation (NSF)-funded Nanosystems Engineering Research Center (ERC) for Nanotechnology Enabled Water Treatment (NSF NEWT) at Arizona State University (ASU) are leveraging the electrochemical properties of conductive coatings to enhance membrane filtration by exploring the multifunctional properties enabled by high conductivity surface coatings. The team discovered that a poly(2-(dimethylamino) ethyl acrylate), or PDMAEA, polymer coated on a carbon nanotube (CNT) is able to achieve calcium sulfate (CaSO4) resistance and dispersal in a Teflon® (PTFE) membrane desalination system. The high conductivity poly(N-isopropylacrylamide) or PNIPAM-CNT membranes provide a simple and effective post treatment strategy to remove the deposited scale by bubbles generated by the water splitting process. (See figures 1 and 2.)
Impact/Benefits
Biofouling of membrane surfaces poses significant operational challenges and multi-billion-dollar costs for desalination and wastewater reuse applications. To help meet these challenges, electrochemical coatings provide membranes with a wide range of functionalities that are beneficial for their performance. For example, early fouling events can be monitored directly on the membrane. Flux and selectivity can then be tailored using electrochemical reactions, while fouling and scaling can be dislodged in-situ without the use of chemicals.
Explanation/Background
Building on prior successful proof of concept work, the NEWT-ERC research team sought to develop new coating materials with enhanced fouling dispersal capacity for a wide range of foulants. A goal was to synthetize and characterize stimuli-responsive polymer coatings and quantify the energy consumption for fouling dispersal in a continuous flow membrane cell. Finally, the team identified early fouling events based on in-situ surface sensing during membrane filtration.
NSF NEWT ERCs studies address three primary barriers to fouling monitoring and removal: first, membranes require stable high conductivity or ultra anti-scaling coatings to maintain high performance at scale. Cleaning conditions need to be optimized for the different foulants (e.g. inorganic, biological) and coating types (conductive versus stimuli-responsive). And, foulant detection using in situ sensing provides a complex signal that needs to be characterized for the different types of foulants.
The membranes were functionalized with highly conductive stainless-steel or nanocarbon coatings to provide electrochemical functions to the surface. Then the foulants were dislodged using electrochemically-generated microbubbles or through stimuli-responsive polymers grafted to the electrochemical surface. Hexagonal boron nitride (hBN) with ultra-smooth morphology and unique water-ion-surface chemistry was grown in situ on a target substrate. And then sensing signal was individually assessed in relationship to water flux and then studied in more complex foulant mixtures. The work has resulted in four publications to date.
Location
Houston, Texaswebsite
Start Year
Energy and Sustainability
Energy and Smart Infrastructure
Lead Institution
Core Partners
Fact Sheet
Outcome/Accomplishment
Researchers with the National Science Foundation (NSF)-funded Nanosystems Engineering Research Center (ERC) for Nanotechnology Enabled Water Treatment (NSF NEWT) at Arizona State University (ASU) are leveraging the electrochemical properties of conductive coatings to enhance membrane filtration by exploring the multifunctional properties enabled by high conductivity surface coatings. The team discovered that a poly(2-(dimethylamino) ethyl acrylate), or PDMAEA, polymer coated on a carbon nanotube (CNT) is able to achieve calcium sulfate (CaSO4) resistance and dispersal in a Teflon® (PTFE) membrane desalination system. The high conductivity poly(N-isopropylacrylamide) or PNIPAM-CNT membranes provide a simple and effective post treatment strategy to remove the deposited scale by bubbles generated by the water splitting process. (See figures 1 and 2.)
Location
Houston, Texaswebsite
Start Year
Energy and Sustainability
Energy and Smart Infrastructure
Lead Institution
Core Partners
Fact Sheet
Impact/benefits
Biofouling of membrane surfaces poses significant operational challenges and multi-billion-dollar costs for desalination and wastewater reuse applications. To help meet these challenges, electrochemical coatings provide membranes with a wide range of functionalities that are beneficial for their performance. For example, early fouling events can be monitored directly on the membrane. Flux and selectivity can then be tailored using electrochemical reactions, while fouling and scaling can be dislodged in-situ without the use of chemicals.
Explanation/Background
Building on prior successful proof of concept work, the NEWT-ERC research team sought to develop new coating materials with enhanced fouling dispersal capacity for a wide range of foulants. A goal was to synthetize and characterize stimuli-responsive polymer coatings and quantify the energy consumption for fouling dispersal in a continuous flow membrane cell. Finally, the team identified early fouling events based on in-situ surface sensing during membrane filtration.
NSF NEWT ERCs studies address three primary barriers to fouling monitoring and removal: first, membranes require stable high conductivity or ultra anti-scaling coatings to maintain high performance at scale. Cleaning conditions need to be optimized for the different foulants (e.g. inorganic, biological) and coating types (conductive versus stimuli-responsive). And, foulant detection using in situ sensing provides a complex signal that needs to be characterized for the different types of foulants.
The membranes were functionalized with highly conductive stainless-steel or nanocarbon coatings to provide electrochemical functions to the surface. Then the foulants were dislodged using electrochemically-generated microbubbles or through stimuli-responsive polymers grafted to the electrochemical surface. Hexagonal boron nitride (hBN) with ultra-smooth morphology and unique water-ion-surface chemistry was grown in situ on a target substrate. And then sensing signal was individually assessed in relationship to water flux and then studied in more complex foulant mixtures. The work has resulted in four publications to date.