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
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.