Project Lead(s): David Sinton
There is a great need for fresh water in many low-income countries, such as Vietnam.
Water purification is required to meet the daily needs of remote populations, but the most impacted regions also lack the energy required for current purification or desalination processes.
The objective of the project was to develop a scalable, energy-efficient water purification method based on ion concentration polarization (ICP).
In 2011, the project team presented a method to concentrate ions from water using a simple channel structure and a uniform non-porous membrane that is inexpensive and amenable to mass-fabrication.
In this project, they adapted the approach to water purification by separating ions and impurities out of the water stream.
The results of this study demonstrated that out-of-plane, scalable and energy-efficient desalination of water using ICP is feasible.
The project team also showed that out-of-plane stacking of microfluidic layers and non-porous membranes presents opportunities for practical, low-cost water desalination devices.
Experimental results established that using larger non-porous membranes for ICP yields larger depletion boundaries and higher energy efficiency.
Flow rate variation was found to have a negligible impact on energy efficiency, since the size of the depletion boundary adjusted to yield a consistent amount of purified water for a given applied voltage.
Out-of-plane ICP desalination was demonstrated for a 500 mM salt solution.
A three-level device was developed to demonstrate scalability and was found to have a three-fold improvement in functional density over current planar designs.
Other scale-up activities for the project have not yet been completed, as the project team remains focused on developing the prototype. However, co-funding and additional support is being sought.
Information on the work done to date has been published in Lab-on-a-Chip.