Inspired by membranes in the body tissues of living organisms, scientists have combined aramid nanofibers used in Kevlar with boron nitride to construct a membrane for harvesting ocean energy that is both strong like bone and suited for ion transport like cartilage.
The research, published December 18 in the journal Joule, overcomes major design challenges for technologies that harness osmotic energy (pressure and salinity gradient differences between freshwater and ocean water) to generate an eco-friendly and widely available form of renewable energy.
Osmotic energy generators vary less from one day to the next than solar and wind energy farms, making them more reliable than these green energy staples. However, the clay, graphene oxide, MXene, and molybdenum disulfide nanomaterials commonly used in membranes tend to collapse and disintegrate in water.
While nanosheets made from boron nitride have recently shown promise, remaining stable as temperatures rise and not easily reacting with other substances, membranes made from boron nitride alone are not hardy enough to withstand water for a long time either, rapidly beginning to leak ions as they develop microscopic cracks.
“New advanced boron nitride composite membranes with novel and robust properties will solve this problem, which is in high demand now,” says Weiwei Lei, the lead scientist of this project in Australia, a Senior Research Fellow at Deakin University‘s Institute for Frontier Materials (IFM).
“Osmotic energy represents an enormous resource for humankind, but its implementation is severely limited by the availability of the high-performance ion-selective membranes,” says Nicholas Kotov (@kotov_group), the lead scientist in the US, a professor of engineering at the University of Michigan.
Lei, Kotov, and their colleagues set out to solve this problem by turning to the tissues of living creatures as a blueprint, observing that many different varieties of high-performance ion-selective membranes are needed to facilitate the biological reactions in their bodies. They noted that while soft tissues, such as cartilage, kidney membranes, and basement membranes, allow ions to pass through with ease, they are weak and flimsy. In contrast, bones are exceptionally strong and stiff, but without the benefit of efficient ion transport.
“We found a way to ‘marry’ these two types of materials to obtain both properties at the same time, using aramid nanofibers that make flexible fibrous materials similar to cartilage and boron nitride that makes platelets similar to bone,” Kotov says.
“Our bio-inspired nanocomposite membranes have certain advantages such as high robustness and being easier to fabricate and offering greater multifunctionality than the membranes made of a single material,” Lei says.
The researchers constructed the hybrid membrane using layer-by-layer-assembly, a method for recreating layered complex composites that works especially well for water technologies. They applied pressure to one reservoir of the aramid-boron nitride membrane in sodium chloride solution to observe its current and compared it with other nanomaterial membranes, finding that the narrowness of its channels allows it to attract sodium cations and repel chloride anions better than other porous composites. Lei, Kotov, and colleagues also repeatedly rinsed the membrane in sodium chloride for twenty cycles to monitor its stability, finding that it continued to function optimally after 200 hours.
“Our new composite membrane has an adjustable thickness and high stability at temperatures ranging from 0 to 95 degrees Celsius and at a pH of 2.8 to 10.8,” Lei says.
“Inexpensive components and membrane longevity makes harvesting ocean energy realistic,” says Dan Liu, the lead author of the paper, also at Deakin IFM.
Altogether, the researchers concluded that the aramid-boron nitride membrane is well suited to withstand a wide range of conditions they would expect it to encounter while generating osmotic energy. They also believe the technology is highly scalable, especially since both of its components are inexpensive. Aramid nanofibers can even be gathered from discarded Kevlar fabric.
“These are the best performing membranes known so far,” says Kotov. “However, they are not yet fully optimized. Even better performance can potentially be obtained.”
Go deeper with Bing News on:
Harvesting ocean energy
- Shearwater collaborates with Norwegian operators on seismic survey tech
Norwegian offshore seismic vessel player Shearwater GeoServices has joined forces with Equinor, Vår Energi and Lundin Energy Norway to accelerate the development and commercialisation of a sustainable ...
- Shearwater, Equinor, Lundin, Vår Energi Working on Marine Vibroseis Tech for Seismic Surveys
Marine seismic services company Shearwater GeoServices and the Norwegian oil and gas firm Equinor are extending their seismic ...
- Computing for Ocean Environments: Bio-Inspired Underwater Devices & Swarming Algorithms for Robotic Vehicles
MIT ocean and mechanical engineers are using advances in scientific computing to address the ocean’s many challenges, and seize its opportunities. There are few environments as unforgiving as the ...
- Computing for ocean environments
Ocean engineers and mechanical engineers at MIT, including Wim van Rees, Michael Benjamin, and Pierre Lermusiaux, are utilizing advances in scientific computing to address the ocean’s many challenges, ...
- Indian startup could revolutionize ocean farming with its 'sea combine harvester'
Often used to wrap sushi and flavor soups, seaweed has much greater potential -- both as a food and for use in a wide range of products from cosm ...
Go deeper with Google Headlines on:
Harvesting ocean energy
Go deeper with Bing News on:
Osmotic energy generators
- Osmotica Pharmaceuticals Announces Corporate Name Change to RVL Pharmaceuticals plc With New Ticker Symbol 'RVLP'
This headline-only article is meant to show you why a stock is moving, the most difficult aspect of stock trading. Every day we publish hundreds of headlines on any catalyst that could move the ...
- Improving Blue Energy Efficiency with a MXene/GO Membrane
Study: Mechanically intensified and stabilized MXene membranes via the combination of graphene oxide for highly efficient osmotic power production. Image Credit: Brett Allen/Shutterstock.com The ...
- MXene Membrane Has Promising Application for Osmotic Energy Extraction
In theory, harvesting osmotic energy reflects the Gibbs free energy of blending ... Despite the growing attentiveness in configurable membranous vesicles for blue power generation, a reasonable ...
- DuPont combines subsea technology with RO
DuPont Water Solutions (DWS) specialises in sustainable water purification and separation technologies, including ultrafiltration, reverse osmosis (RO) membranes and ion exchange resins. DuPont has ...
- Intestinal Permeability – A New Target for Disease Prevention and Therapy
Local pressure, electrochemical and osmotic gradients determine the direction of flow. In contrast to the tight junction the defects at cell shedding sites are too wide to permit local inwardly ...