Scientists at Brown University have demonstrated a promising new water purification technology that takes advantage of the tiny gaps in stacked sheets of graphene to filter out contaminants with great efficiency. Graphene is a two-dimensional sheet of carbon measuring just a single atom in thickness and possesses a range of highly useful attributes.
Among these is an ability to act as a water filtering tool, with the material able to be fashioned into membranes that allow the passage of water molecules while trapping impurities in the liquid.
This could include pulling salt from seawater, or cleaning contaminants from the water sources. The Brown University team were investigating how these types of technologies might be improved upon, and were investigating how stacks of graphene sheets could be manipulated in different ways to produce better results.
When these graphene sheets are stacked on top of one another, it creates nanochannels in between them that can be used for filtration. This means water can be fed into the stack, and runs through the material lengthways, contaminants filtering out as it goes.
The way the Brown University team sees it, things would be far more efficient if the water could instead be filtered in a vertical direction, and only need to pass through the thickness of the material, rather than its entire length. The researchers found a way around this by first stacking the graphene sheets onto an elastic substrate that has been stretched out.
In testing, water vapor was able to pass through the vertical channels easily while a larger molecule, called hexane, was successfully filtered out.
“So, for example, water can pass through, but organic contaminants or some metal ions would be too large to go through. So you could filter those out.”
The team is now continuing to develop its novel water filter, and hopes that it can one day find use in household and industrial applications. By increasing the efficiency of water purification, the innovation can drastically lower cost and energy consumption associated with water filtering, which would make it more environmentally friendly.
Graphene has been thought of as a future wonder material for decades, with promises of revolutionizing everything from structural materials to medicine and energy storage solutions, but only recently such innvations are starting to make thier way out of the lab and into products. Now it is possible to buy batteries containing graphene which have a higher performance than standard lithium-ion batteries.
Graphene products still face the problem of graphene being in very short global supply, keeping the prices high and thus dropping the market appeal of graphene products. however, as new and more economical ways of producing graphene are invented and scaled up, graphene will achieve the positive feedback loop of economies of scale.