Water plays a major part in our everyday life for activities such as kayaking, ice skating and swimming. In a wider context than leisure there are however way more important uses of water, a commonly underappreciated translucent liquid considering that it is essential for our survival and makes up the majority of our body weight. Since we lose water all the time doing activities such as the aforementioned the bodily storage has to be refilled, a task that is not always straightforward since the body does not cope with water impurities very well. A lot of investments have therefore gone into facilities focusing on compensating for this weakness by purifying dirty water and saline water to drinking water prior to drinking. State of the art water treatment plants unfortunately require a lot of energy for purification, a drawback that can be considered substantial from at least three perspectives; the environmental, economics and health perspectives.
Water desalination processes used today require large scale facilities due to the high pressures required to pump sea water through narrow pore filtration membranes. High energy consumption is generally considered to be an environmental as well as economic drawback. The people that are in the most pressing need of these processes are not seldom situated in countries with a warm and dry climate, where there is a lack of safe drinking water supplies. They might not be in need of a large scale treatment plant and might not have the economical prerequisites to invest in such a thing. Therefore there is a need for a less energy consuming process that can be used on a smaller scale.
Fortunately, you do not have to look far to find such a process. In fact, it is taking place all the time inside our bodies as well as in trees surviving on dirty water in warm countries. All living cells in Nature with the need of using water are doing this all the time through the use of proteins named Aquaporins. One way of illustrating this process is to think of a synthetic filter membrane, where the pores are open for water transport whereas the non-porous part of the filter hinders the passage. In Nature, the Aquaporins are the pores and the cell membrane is the non-porous constituent. This process obviously works without excessive amounts of added pressure and is therefore a good model system to use for the development of an energy efficient water treatment filter.
The project I am involved in aims to take water treatment to the next level. By mimicking Nature we can achieve an energy efficient, low cost and, if desired, small scale process that produces cleaner water than the present state of the art. The approach is to develop a filter membrane consisting of a lipid bilayer incorporating aquaporins, which essentially is a simplified cell membrane. A mesoporous silica bilayer support is used to provide the filter with mechanical stability while maintaining the aqueous environment on both sides of the bilayer for the aquaporins to thrive. This way we will achieve a low cost, environmentally friendly process that is specific enough to remove even small substances such as pharmaceutical residues and microplastics from our drinking water.