With a world population in excess of seven billion, the world’s water resources are already stretched. As per UN population forecasts, another two billion human beings will be added to the planet over the next four decades. This is an alarming situation, which needs to be addressed effectively at a global level. Many communities around the world are already facing the challenges of limited access to fresh water due to both natural and manmade causes. This is where seawater desalination technology can help tide over the global water crisis.
The basic challenge with the existing seawater desalination technologies is that they are expensive, which makes fresh water unaffordable for an average household. A team of chemists at the University of Texas at Austin and the University of Marburg in Germany has come up with a promising solution. The team has introduced a new desalination process that involves creation of a small electrical field that removes salts from the seawater. The researchers say this new method is dramatically simpler than traditional techniques and consumes less energy. In fact, the process can be conducted with a store-purchased battery.
The journal Angewandte Chemie has published details of this technique, which is called electrochemically mediated seawater desalination. The researchers apply a tiny voltage of 3.0 volts to a plastic chip filled with seawater in order to achieve desalination. The chip has a micro-channel with two branches. At the junction of the channel an embedded electrode neutralizes some of the chloride ions in seawater. This produces an “ion depletion zone” that enhances the local electric field compared with the rest of the channel. This change in the electric field is sufficient to redirect salts into one branch, enabling the passage of desalinated water from the other branch.
The researchers have already achieved 25 percent desalination with this process, and believe that the goal of 99 percent desalination to make the water fit for drinking is not beyond reach.