Shortage of drinking water is being faced by more and more communities worldwide. On the other hand, the current methods of turning salt water, which is abundant, into drinking water are expensive and damaging to the environment, and therefore not a viable long-term solution. However, a team of researchers at the University of Alexandria have recently come up with a simpler, cheaper and much cleaner method of turning seawater into drinking water. Their solution could potentially bring clean drinking water to parts of the world, such as North Africa and the Middle East, which do not have sufficient access to it.
Currently, there are several large desalination plants in operation, but these work on the basis of a multi-step process. These plants utilize the process of reverse osmosis, which needs expensive infrastructure and vast amounts of electricity to function. In addition to that, such plants also pollute the oceans by releasing back into them huge quantities of highly concentrated salt water, as well as other pollutants, which adversely affects marine environments.
This is why the method developed by the University of Alexandria team is so promising. Their method involves using materials, which can be manufactured easily and cheaply in most countries worldwide, in order to purify the water. Furthermore, the method they developed does not rely on electricity overmuch.
The tech they developed is based on a method of separating liquids and solids called pervaporation. The latter is a simple process performed in two steps. The first step is filtering the seawater via a ceramic or polymeric membrane, and the second step calls for the vaporizing of, and collecting the condensed water. This final step does not depend of electrically generated heat, which makes pervaporation a lot more energy efficient, as well as cleaner and faster than currently used water desalination methods.
Pervaporation is not a new process, but until now the membrane that is needed for it to work was very expensive and difficult to make. However, the researchers have also invented a brand new, salt-attracting membrane, which is embedded with cellulose acetate powder. This membrane is used in step one of this process, while the acetate powder needed to make it is derived from wood pulp and can cheaply and easily be made in any lab.
According to the researchers, this method can be used to quickly desalinate highly concentrated seawater, while also purifying it even if it is very contaminated. The membrane they use is also capable of capturing pollutants and salt crystals and thereby greatly reducing the polluting aftereffects of using this method. Since fire can be used as a source of heat, the method is perfectly suitable to be used anywhere in the world. All in all, this looks like a very promising solution for third world countries facing drinking water shortages.