UK Scientists Create Graphene-Based Sieve To Combat World Water Shortage Crisis

[♥ Lily ♥]

Scientists Create Graphene-Based Sieve
That Is Able To Make Seawater Drinkable

4th April, 2017

The prospect of drinkable seawater has moved a step closer with the invention of a graphene-based sieve.

The sieve, developed by UK-based researchers, is able to remove any traces of salt – meaning there is a real possibility of providing clean drinking water to millions of people who struggle to gain access.

The team at the University of Manchester, where colleagues won a Nobel Prize in 2010 for first extracting graphene, have managed to precisely control the sizes of pores in a graphene oxide sieve.

The graphene sieve would be able to make seawater drinkable for millions

Their discovery allows them to filter out salts from water to make it safe to drink, according to the Nature Nanotechnology journal.

Dr Ram Devanathan, from the Pacific Northwest National Laboratory in Richland, wrote: “The ultimate goal is to create a filtration device that will produce potable water from seawater or wastewater with minimal energy input.”

Graphene oxide membranes have already been proven to filter out large salts but it is only now that the team have worked out how to filter out common salts.

Previous work had shown that graphene oxide membranes became slightly swollen when immersed in water, allowing smaller salts to flow through the pores along with water molecules.

However, the researchers demonstrated that placing walls made of epoxy resin (a substance used in coatings and glues) on either side of the graphene oxide membrane was enough to stop the expansion.

With man-made climate change reducing cities’ water supplies, countries have been increasingly investing in “desalination” technologies.

The UN has predicted that around 1.2 billion people, or 14% of the world’s population, will experience difficulties sourcing clean water by 2025.

Professor Rahul Nair, who led the team of researchers in Manchester, said it is a “significant step forward” that will “open new possibilities for improving the efficiency of desalination technology”.

What is graphene?

Graphene is the world’s first 2D material and was first isolated in 2004. It is incredibly light and flexible but immensely tough – around 200 time stronger than steel. It is the thinnest material on Earth – one MILLION times thinner than the human hair – and acts as a perfect barrier, able to prevent even helium from passing through it. Made up of a hexagonal lattice of carbon atoms in a honeycomb like structure, graphene could one day be used to create flexible phones, wearable technology and lightweight planes.

(Top pic: University of Manchester)

https://uk.yahoo.com/news/scientists...102910229.html

[♥ Lily ♥]

Peer into a glass of drinking water and you are looking at a drop of human history—the water we consume today has been around in one form or another for thousands of years, continually recycled through the atmosphere and back into our cups.


Photograph by Jonathan Hodgson

A Clean Water Crisis

The water you drink today has likely been around in one form or another since dinosaurs roamed the Earth, hundreds of millions of years ago.

While the amount of freshwater on the planet has remained fairly constant over time—continually recycled through the atmosphere and back into our cups—the population has exploded. This means that every year competition for a clean, copious supply of water for drinking, cooking, bathing, and sustaining life intensifies.

Water scarcity is an abstract concept to many and a stark reality for others. It is the result of myriad environmental, political, economic, and social forces.

Freshwater makes up a very small fraction of all water on the planet. While nearly 70 percent of the world is covered by water, only 2.5 percent of it is fresh. The rest is saline and ocean-based. Even then, just 1 percent of our freshwater is easily accessible, with much of it trapped in glaciers and snowfields. In essence, only 0.007 percent of the planet's water is available to fuel and feed its 6.8 billion people.

Due to geography, climate, engineering, regulation, and competition for resources, some regions seem relatively flush with freshwater, while others face drought and debilitating pollution. In much of the developing world, clean water is either hard to come by or a commodity that requires laborious work or significant currency to obtain.

Water Is Life

Wherever they are, people need water to survive. Not only is the human body 60 percent water, the resource is also essential for producing food, clothing, and computers, moving our waste stream, and keeping us and the environment healthy.

Unfortunately, humans have proved to be inefficient water users. (The average hamburger takes 2,400 liters, or 630 gallons, of water to produce, and many water-intensive crops, such as cotton, are grown in arid regions.)

According to the United Nations, water use has grown at more than twice the rate of population increase in the last century. By 2025, an estimated 1.8 billion people will live in areas plagued by water scarcity, with two-thirds of the world's population living in water-stressed regions as a result of use, growth, and climate change.

The challenge we face now is how to effectively conserve, manage, and distribute the water we have. National Geographic's Freshwater Web site encourages you to explore the local stories and global trends defining the world's water crisis. Learn where freshwater resources exist; how they are used; and how climate, technology, policy, and people play a role in both creating obstacles and finding solutions. Peruse the site to learn how you can make a difference by reducing your water footprint and getting involved with local and global water conservation and advocacy efforts.

http://www.nationalgeographic.com/fr...er-crisis.html