A New Frontier In Drinking Water From MIT

Tell us about the Research Laboratory of Electronics (RLE) and the work you do? 
The research laboratory of electronics (RLE) is MIT’s leading entrepreneurial interdisciplinary research organization. I have mainly worked on mass transport phenomena on the ion-exchange membrane.

What is the science behind the portable desalination unit? 
The Han group at MIT has been investigating fundamental ion transport processes in ion-exchange membranes, which led to the discovery of the novel Ion Concentration Polarization (ICP) desalination process. The ICP process is an alternating stack of cation-exchange membranes and flow channels. One of the most critical advantages of the ICP process is that it enables both purification (removing contaminants) and desalination (removing salt) simultaneously, eliminating the pretreatment process in a filter-less manner. The other advantage is the scalability since the system can be built from single-person use cases to small villages (>100 people) by simply stacking more cation-exchange membranes and flow channels. These advantages make the ICP process ideal for portable purification/desalination systems, to be installed in small villages where resources are limited. Our group has already developed a prototype of a portable desalination unit and has successfully implemented field testing for natural seawater desalination.

How will this help vulnerable communities? 
There are many ways to define vulnerable communities. We see this technology being most beneficial to communities whose water resources are the most contaminated/salinized. There are existing technologies that can treat brackish groundwater, and some can do so at greater efficiency than we can, but when the salinity and other contamination are high, we see our technology as the best solution. Communities who have highly contaminated or salinized groundwater, or who live on the coast and temporarily lose access to their usual water source (due to storms, drought, geopolitical events, or other crises) will find our device more effective and accessible than anything else on the market.

Where is future research in this field evolving? 
Today, filtration is the most widely used technology to remove pathogens (water purification) and salt (desalination) from contaminated and salinized water. Reverse osmosis (RO) is one of the leading filtration technologies enabling purification and desalination. However, RO process requires continuous monitoring and maintenance to ensure normal operation. Once the RO membrane is fouled, blocked or damaged by an unexpected influx of contaminants, the RO membrane needs to be replaced. RO is an appropriate desalination solution for plant-scale operations supporting population-dense, urban areas, where technical and logistical support are easily available. However, RO is not a viable option for remote and sparsely populated areas, expeditionary military operations, disaster relief, and small island communities where supporting resources are limited. The next-generation water treatment (purification/desalination) technology needs to address these critical unmet needs, with a flexible operation (at various production scales, maintenance-free operation (so that non-experts can operate the system), with minimal environmental and energy footprints.