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The Shell Center for Sustainability's mission is to foster an interdisciplinary program of research, outreach, and education to address actions that can be taken to ensure the sustainable development of communities' living standards, interpreted broadly, to encompass all factors affecting the overall quality of life.

Self-sustained Portable Capacitive Deionization Device for Water Purification

Deionization at a low cost  

PI: Dr. Jun Lou, Department of Mechanical Engineering and Materials Science 
Co-PI: Dr. Qilin Li, Department of Civil and Environmental Engineering 
Co-PI: Dr. Pulickel Ajayan, Department of Mechanical Engineering and Materials Science  

Pic Jun Lou 11  Pic Qilin Li 11  Pic Pulickel Ayayan 11 
Jun Lou Qilin Li Pulickel Ajayan
Project Background   

Water has been one of the top problems facing human being for centuries. A large proportion of today’s world population still suffers from drinking water shortages. Meanwhile, 98% of the water on earth is sea water which is not drinkable because of high salt concentrations. One possible solution to the challenging drinking water problem obviously lies on our ability to desalinate sea water. There are several mature technologies for sea water or brackish water desalination. The most widely used are thermal processes and reverse osmosis (RO). However, both technologies are very energy intensive.

Capacitive deionization (CDI), on the other hand, is a desalination/purification technique with a lot of promise as a cheaper and more efficient alternative. This makes it attractive for portable, point of use treatment devices. In order for the CDI devices to work off-grid, which will be very important for their utilization in both remote areas and urban areas where minimum energy foot-print is allowed, solar energy with reasonable cost becomes a very attractive option. In this regard, dye sensitized solar cells (DSCs), an emerging low cost (~1/3 cost compared to Si based solar cells) solar harvesting technique, is a perfect candidate for such integration.

Therefore, the overall objective of this research is to create a self-sustained portable water purification system integrating energy efficient CDI with low cost DSCs. We will develop innovative nano-carbon materials for high efficiency and versatile CDI electrodes, and integrate the high efficiency CDI with low-cost DSCs. The off-grid operation and small foot-print of the proposed portable system have minimum impact on the oftentimes overloaded aging urban energy and water infrastructures. It also has great potentials in military and domestic applications where more energy intensive water purification technologies are not viable.

In this one-year project, we plan to explore this exciting technology from both materials and system perspectives. We will first fabricate high quality 3-D graphene/CNT composites that have desired surface and electrical properties with sufficient mechanical integrity. Then, we plan to utilize the novel graphene/CNT composite as electrode material in both CDI and DSC devices for higher efficiency operations. Finally, we will directly connect a DSC module consisting of several individual cells with proper output voltage and current as external DC power source for our fabricated CDI devices.

Our end-of-project goal is to successfully fabricate both CDI and DSC devices using novel 3-D graphene/CNT composite. We also expect to have an operational lab demo of a well-integrated CDI-DSC system by the completion time of the project.


Project Report 


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