The Water Innovation and Research Center at the University of Bath in the United Kingdom, in partnership with Indonesia’s Bogo Agricultural University and the University of Johannesburg in South Africa have developed a desalination process that has the potential to be used in mobile, solar powered mechanisms. Desalination is the process of removing salt from water, which can then be used as safe drinking water in the event of a disaster, or in areas that do not have sufficient supply.
Currently there are other ways to remove salt from water. One being reverse osmosis where the water is passed through a series of membranes, which trap the salt and impurities. Another way, which has been used for thousands of years is distillation. Thermal distillation is when water is boiled and the steam is collected, the heavy salt is left behind. Usually these processes are done in large industrial plants and use a lot of energy. These solar powered units are low-energy and would be helpful in smaller, secluded communities that do not have a sufficient water supply, or if there is an emergency where a fresh water supply is diminished.
Using a 3D printer, the team created a unit with two chambers. When activated, positively charged salt ions (cations) and negatively charged salt ions (anions) flow between the chambers through tiny micro-holes. The process only moves in one direction, separating the salt from the water. This process only leaves the salt behind, which can then be crystallized and distributed for other uses. In other desalination processes, the leftover concentrated brine mixture is typically pumped back into the ocean, which can disrupt the natural ecosystem.
Currently the prototype is able to remove approximatley 50 percent of the salt, however 90 percent needs to be removed for human consumption. They believe it’s just a matter of finding the right porous material to pump ions through. They are experimenting with different materials, including viruses that replicate within bacteria. These are known as bacteriophages and they create a filmy membrane, which were found to be capable of separating salt from water, even moving it on one direction only. This team is the first to be experimenting desalination with bacteriophages. There is still some work to do, and they believe in as little as five years their project could revolutionize the way water is desalinized, creating clean drinking water for those in need in a more energy efficient way.
