Global collaboration for global problems: Partnership tackles world water shortages

The depletion of freshwater resources is a mounting problem in our changing world. Growing population and climate change are combining to cause concern about water shortages, not just for today’s population, but the next generation.

Agriculture accounts for about 70 percent of the world’s fresh water consumption. And with a growing population and expanding middle class, the demand for food is growing with it.

By 2030, the global middle class is estimated to grow from 2 billion today to 4.9 billion and this will significantly increase the water required for food production. Food production will need to grow by 69 percent by 2035 to feed this growing population. Water withdrawal for energy, used for cooling power stations, is also expected to increase by over 20 percent.

All of this together means water demand globally is projected to increase by 55 percent between 2000 and 2050.

The problem of looming water shortages is a real one. One that will have a material impact on the future of not just human beings, but all other ecosystems reliant on freshwater.

Facing a bleak future if the problem isn’t solved, researchers are working hard to prevent the worst effects. Among those are scientists from the University of Manchester who have teamed up with Khalifa University of Science and Technology in Abu Dhabi to invent a novel desalination method.

The team has developed graphene-based membranes to take salts out of water that are proving far more effective than the current most popular and widespread method of desalination.

Currently, forcing large quantities of saltwater through membranes and using reverse osmosis to remove the salt is only effective with water with high salt content. For those with a lower salt content, like brackish water, the method doesn’t work well enough.

As all sources of water are going to be needed going forward, a method that works on all contents is essential. That’s what the team has developed.

Their new ion-selective membranes incorporating graphene oxide are used in electromembrane desalination processes such as electrodialysis and membrane capacitive deionization. This method has been shown to work on even low salt content water as the ions in the saltwater can be driven out by an electric field.

“We prepared the electrostatically-coupled graphene oxide nanocomposite cation exchange membrane, where all the ion exchange groups are provided by ionic conducting nanomaterials,” explained Professor Linda Zou from Khalifa University of Science and Technology.

“The collaboration between two teams provided great support to each other in complementary aspects of the research, and led to positive research outcomes, and more to come.”

Graphene is the world’s first two-dimensional material, it is more conductive than copper, one million times thinner than a human hair. It is even capable of forming the perfect barrier to liquids and gases including helium – the hardest gas to block.

The team published their findings in the Journal of Membrane Science, the third paper to be published from the project, detailing the success so far.

Peter Budd, Professor of Polymer Chemistry at The University of Manchester, said: “This collaboration is enabling us to develop both membranes that like positively charged ions and membranes that like negatively charged ions, and together they offer exciting possibilities for helping achieve the global goal of clean water for all”.