A Desalination Battery

Abstract

Water desalination is an important approach to provide fresh water around the world, although its high energy consumption, and thus high cost, call for new, efficient technology. Here, we demonstrate the novel concept of a "desalination battery", which operates by performing cycles in reverse on our previously reported mixing entropy battery. Rather than generating electricity from salinity differences, as in mixing entropy batteries, desalination batteries use an electrical energy input to extract sodium and chloride ions from seawater and to generate fresh water. The desalination battery is comprised by a Na(2-x)Mn(5)O(10) nanorod positive electrode and Ag/AgCl negative electrode. Here, we demonstrate an energy consumption of 0.29 Wh l(-1) for the removal of 25% salt using this novel desalination battery, which is promising when compared to reverse osmosis (~ 0.2 Wh l(-1)), the most efficient technique presently available.

Time-dependent ion selectivity in capacitive charging of porous electrodes

“…In commercial desalination technologies, such as reverse osmosis and multistage flash distillation, freshwater is produced at relatively high energy cost and often requires re-mineralization for human consumption. For brackish water or wastewater it can be advantageous to use a different type of technology, namely techniques where ions are removed from the feed water under the influence of electrical field effects, such as in electrodialysis [8,9], capacitive deionization [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], membrane capacitive deionization [29][30][31][32][33][34], desalination using microchannels [35], batteries [36], microbial desalination cells [37] and wires [38]. Such techniques have the potential to be energy-efficient as they focus on the removal of the (often relatively few) ions in the water to obtain freshwater in this way.…”

Effect of electrode thickness variation on operation of capacitive deionization

“…Technologies where ions are removed from water by electrical fields include electro-deionization and electrodialysis [1,2], water desalination using microchannels [3] and batteries [4], capacitive deionization (CDI) , and membrane capacitive deionization [31][32][33][34][35][36]. Recently a new promising application with focus on generating energy from mixing fresh and salt water has been demonstrated, which makes use of a capacitive flow process similar to that employed in CDI [37,38].…”

Hybrid capacitive deionization with anion-exchange membranes for lithium extraction

“…A variety desalination technology have been developed over year. Reverse osmosis and multistage flash distillation require a large electrical energy input which accounts for an approximately 50% of its costs [4]. Forward osmosis is a promising method that utilizes lower temperatures (60°C) than MFD but still requires energy.…”

“…Finally, a new concept of a "desalination battery" which has configuration similar to CDI, but with different electrode materials, was investigated. In this case, system is consist of cationic sodium insertion electrode and a chloride-capturing anionic electrode, made of Ag [4]. Batteries electrode pose higher specific capacity and lower energy requirement than capacitive deionization [4].…”