Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 7, 2014
Previous Article Next Article

Performance of a mixing entropy battery alternately flushed with wastewater effluent and seawater for recovery of salinity-gradient energy

Author affiliations

Abstract

Salinity-gradient energy, also referred to as blue energy, is a largely untapped source of renewable energy. Coastal wastewater treatment plants discharge a continuous stream of low salinity effluent to the ocean and are thus attractive locations for recovery of blue energy. One method of tapping this gradient is a “mixing entropy battery” (MEB), a battery equipped with anionic and cationic electrodes that charges when flushed with freshwater and discharges when flushed with seawater. We constructed a plate-shape MEB, where the anionic electrode was Ag/AgCl, and the cationic electrode was Na4Mn9O18 (NMO). Over a single cycle with a single cell, the net energy recovery was 0.11 kW h per m3 of wastewater effluent. When twelve cells were connected in series, the net energy recovery (energy produced after subtracting energy invested) was 0.44 kW h per m3 of wastewater effluent. This is 68% of the theoretical recoverable energy of 0.65 kW h per m3 of wastewater effluent. We conclude that (1) wastewater effluent can be effectively used for charging of a MEB, (2) cells in series are needed to optimize net energy recovery efficiency, (3) there is a trade-off between net energy recovery efficiency and capital investment, (4) there is a trade-off between net energy recovery efficiency and power output, and (5) new electrode materials are needed to increase capacity, decrease cost, and to avoid release of Ag to seawater.

Graphical abstract: Performance of a mixing entropy battery alternately flushed with wastewater effluent and seawater for recovery of salinity-gradient energy

Back to tab navigation

Supplementary files

Article information


Submitted
01 Apr 2014
Accepted
10 Apr 2014
First published
10 Apr 2014

Energy Environ. Sci., 2014,7, 2295-2300
Article type
Paper
Author version available

Performance of a mixing entropy battery alternately flushed with wastewater effluent and seawater for recovery of salinity-gradient energy

M. Ye, M. Pasta, X. Xie, Y. Cui and C. S. Criddle, Energy Environ. Sci., 2014, 7, 2295
DOI: 10.1039/C4EE01034E

Social activity

Search articles by author

Spotlight

Advertisements