The Wonder of Graphene: Making Seawater Drinkable

Posted by ACS Material, LLC on October 23rd, 2019

Clean, drinkable water is a challenge for places without ready, easy access to the precious resource. It's sadly ironic since the element makes up 71% of the planet, but roughly only 0.4% is potable for its inhabitants. Looking at the numbers, it's easy to say that the answer to the scarcity is right in front of people. But, consuming mineral-rich ocean water isn't feasible - or is it?

A group of dedicated individuals found an effective way to desalinate seawater with the help of a "wonder material."

What It Is

Graphene is the thinnest and lightest element ever obtained. It's a two-dimensional (2D) crystal made up of a single layer of carbon atoms patterned like a honeycomb. It's also the strongest - known to be tougher than diamond and 300 times harder than steel. With a trait like that, it's almost unbelievable that it's malleable.

These properties moved this allotrope out of the experimental phase to the marketplace. Today, the automotive, electronics, communications, oil, and solar industries are all taking advantage of the semimetal of the future.

People are discovering many applications for it, and now, experts have revealed that there's an addition to its resume: making seawater drinkable.

Desalination Process ft. Graphene

The method of desalinating saltwater isn't new to the public. The first attempt at this process dates back to the 1600s, with its most recent success in Israel. It's known as one of the driest countries, but thanks to the technique, it now makes more freshwater - from the Mediterranean Sea - than it needs.

In large-scale desalination, experts use reverse osmosis. It's when pressure is applied to the seawater, so it'll flow through a special membrane to spaces of lower salinity. This separates H2O and tells the salt, "Na, goodbye."

It sounds simple, but it isn't perfect. Acquiring water for the process is expensive; the figure can go up to ,000 to ,500 per acre-foot. While it's cheaper to recycle what people use every day, for dry places, there's really no other option. Part of the total cost is from the energy used in pre-treating the resource and pumping it through plastic films. This is where the wonder material comes in.

Experts have predicted that if they can use sheets of graphene nanoplatelets instead of thick water purification membranes, the amount of energy they need will be reduced to 15% from 46%. Graphene-based films will also let H2O through while filtering the salt simultaneously.

In 2018, a group of scientists succeeded with just a single use of "graphair," a form of the miracle substance. They even claimed that it can make any liquid consumable no matter how dirty it is.

Desalination by graphene nanoplatelets is giving humans hope that even with Earth's dwindling supply of drinkable water, there's an ocean of methods for better hydration.