In April 2022, MIT researchers achieved a significant breakthrough in portable desalination technology, creating a device that can generate clear and clean drinking water from seawater without the need for filters or high-pressure pumps.

The portable desalination unit, weighing less than 10 kilograms and resembling a small suitcase, has the potential to revolutionise access to safe drinking water, particularly in remote and resource-limited areas.

Unlike existing portable desalination units that rely on filters and energy-intensive pumps, this device employs an innovative technique known as ion concentration polarization (ICP) combined with electrodialysis to remove particles and salts from seawater.

The ICP process utilises electrical fields applied to membranes, which repel charged particles such as salt molecules, bacteria, and viruses. The particles are then funnelled into a separate stream of water and discharged. The remaining salt ions are eliminated through the electrodialysis process.

The researchers, led by senior author Jongyoon Han, a professor of electrical engineering and computer science and of biological engineering, and Junghyo Yoon, the first author of the study, employed machine learning to optimise the combination of ICP and electrodialysis modules. The resulting portable desalination unit runs on low energy consumption, making it ideal for off-grid environments.

The user-friendly device, operated with a single button, continually monitors the salinity level and the number of particles in the water. Once the thresholds for safe drinking water are reached, the device alerts the user. In addition, a smartphone app has been developed to control the unit wirelessly and provide real-time data on power consumption and water salinity.

The researchers conducted successful beach tests at Boston’s Carson Beach, where the portable desalination unit filled a plastic drinking cup with clear, drinkable water in just 30 minutes. The water produced exceeded the quality standards set by the World Health Organization (WHO), with suspended solids reduced by a factor of at least 10. The prototype currently generates drinking water at a rate of 0.3 liters per hour, consuming only 20 watt-hours per liter.

With further development and refinement, this portable desalination unit could make a substantial impact on global access to clean drinking water, improving the lives of millions of people around the world. The researchers are aiming to scale up the production rate and improve the device’s energy efficiency. Additionally, they plan to address water-quality issues beyond desalination, such as detecting contaminants in drinking water more rapidly.