A Swansea University chemical engineering professor has developed a self-cleaning membrane for sustainable water desalination.

Professor Nidal Hilal, Director of the Centre for Advanced Technologies and Environmental Research (CWATER) at http://www.swansea.ac.uk/engineering/)" target="_blank">Swansea University’s College of Engineering has devised an advanced water treatment membrane made of electrically conductive nanofibres which cleans itself.

Self-cleaning membranes offer a critically needed solution to the problem of the unwanted build-up of organic and inorganic deposits on a membrane’s surface that reduces the membrane’s ability to filter impurities.

Water treatment and purification membranes that can easily clean themselves when fouled could make pressure-driven membrane filtration systems used to treat and desalinate water more energy efficient. Conventional methods for cleaning fouled membranes involve expensive and harsh chemical treatments, and often lead to costly and time-consuming water treatment plant shut-downs.

Fouled membranes are also a sustainability issue, as once a membrane becomes fouled, the higher pressure needed to push water through clogged pores significantly increases the plant’s energy consumption. The harsh chemicals used to clean a fouled membrane are also bad for the environment and require neutralising. Thus, finding a way to easily and quickly clean fouled membranes not only makes financial sense, but environmental sense.

Professor Hilal and Professor Raed Hashaikeh from the Masdar Institute in Abu Dhabi, UAE, successfully developed a self-cleaning microfiltration membrane in 2014 but they wanted to take their research a step further and find a way to develop a self-cleaning nanofiltration membrane. While microfiltration membranes are useful for removing larger particles, including sand, silt, clays, algae and some forms of bacteria, nanofiltration membranes can go a step further, removing most organic molecules, nearly all viruses, most of the natural organic matter and a range of salts. Nanofiltration membranes also remove divalent ions, which make water hard, making nanofiltration a popular and eco-friendly option to soften hard water.

To create the membrane, Professors Hilal and Hashaikeh mixed carbon nanostructures with networked cellulose gel and as the mixture dried, the networked cellulose shrank, resulting in much smaller pore sizes.

The teams’ innovative research will help position Abu Dhabi as a leader in membrane desalination research and technology development. The project has already yielded a patent filing, and is hoped to provide the emirate with novel intellectual property in the desalination industry.