Woodruff School of Mechanical Engineering

Faculty Candidate Seminar


Energy extraction from salinity gradients through capacitive mixing


Dr. Marta Hatzell


Penn State


Monday, March 24, 2014 at 11:00:00 AM


MRDC Building, Room 4211


Dr. Shannon Yee


Harnessing the entropic energy released when river and seawater mix could globally provide ~1 terrawatt of renewable power[1]. To capture this energy, three main processes have been used: pressure retarded osmosis (PRO), reverse electrodialysis (RED), and capacitive mixing (CapMix). These three processes are based on reversing three common approaches used to desalinate water, which are reverse osmosis, electrodialysis, and capacitive deionization. The CapMix approach to extract salinity gradient energy is based on controlled ion transfer to and from capacitive or battery electrodes. Suitable materials for energy generation using battery electrodes have not sufficiently advanced as precious metals (e.g. Ag) can be required. In contrast, capacitive electrodes can be made from materials that are both renewable and inexpensive (such as activated carbon), and they can have longer lifetimes than battery electrodes. In this presentation I will summarize the current state of capacitive mixing as a potential means for capturing renewable energy from natural mixing at estuaries, and as an energy recovery mechanism for desalination plants. Furthermore, I will also discuss the effect electric fields have on enhancing the ion migration and energy extracted from capacitive mixing.


Marta C. Hatzell is a PhD candidate in Mechanical Engineering at The Pennsylvania State University. Marta is currently a National Science Foundation Graduate Research Fellow (2011-2014), a PEO fellow (2013-2014), and has received Masters Degrees in Mechanical and Environmental Engineering.


Refreshments will be served.