Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues. Our student Jessica Kobus makes this connection here…

The “battery technology could charge up water desalination” was published February 6, 2016 from University of Illinois at Urbana-Champaign by engineering professor Kyle Smith, and graduate student Rylan Dmello. This news relates to WRE in the hydrology problems of salty water, the lack of freshwater. In summary, this technology has enabled the use of a battery to take salt of out the water. The battery will use the materials in it to draw the salt charged ions out.  These batteries were influenced by the sodium ion battery because it contained salt water. The batteries have two chambers, one positive and one negative side. There is a space in between for the ions to pass through. Once in contact with the water, it will draw out the sodium and chloride ions in the salt water into one chamber. When the battery is charged they flow to the positive side and the salt accumulates there. The other chamber then only has the desalinated water left from that. In a normal battery, the ions just flowed back and forth to the chamber, so Dmello and Smith had to ensure the ions didn’t flow back into the now freshwater, so they put a selective membrane in between to block only the sodium. Today’s current method of doing this is reverse osmosis, which pushes water through a membrane that takes a lot of pressure and energy to keeps the salt out but it is relatively expensive, inefficient and costly(Mohamed). The battery seems to be a better alternative because it uses the least amount of energy and is more efficient because there is less pressure needed for pumping the water through a membrane because now the ions just flow freely. Which results in less energy needed and less cost. Since this battery will run on low voltages they also have the option of running it with solar power (Dexter). This battery method is also has the ability to be small or large depending on the application. In my opinion is that this is not only a cool idea but surprisingly, a good one. At first the article caught my eye because normally when you hear batteries and water, you think electricity and how they don’t go well together, or that once a battery is in water it no longer works. But, this battery that works in and for the water. The only thing missing that I’m curious about is how they are going to take out other pollutants, and is there going to be any negative effect to keep a battery in the water (could it add some kind of pollutant or decompose?) Also, it hasn’t been tested in the actual ocean yet so there definitely needs to be more research and tests done.

This could be a huge positive for the water resource engineers and the world. With the increase threat of loss of fresh water  this can help either slow down the threat, or recycle and use the saltwater now to have the freshwater. This will also decrease our energy consumption.  This is only a prototype right now and still needs further research and testing. They have done test runs on concentrations as equal as seawater environments and have shown to retrieve 80% of the desalinated water. The next step is to try it in actual seawater because they haven’t accounted for other contaminants yet.  In the journal The Future of Seawater Desalination: Energy, Technology, and the Environment, focuses on the main point that water scarcity is one of the biggest challenges our world has right now. This effects all life on earth negatively and is has no easy fix, yet it needs to be fixed for survival. They say how water supply can only be fixed by desalination or water reuse. So this is where the battery comes in and is important because it is a cheaper, and less energy consuming way of desalination than the current method of reverse osmosis. Us as humans are extremely consumptive and not very humble in our use of water. We caused this problem by not thinking beforehand of how to extend water supply or that it will run out eventually. So instead of doing something to prevent this we now have threat of water scarcity which leaves us with the only the option of desalination for a solution. This is a very scary and threatening issue that I feel like people still sweep under the rug because they still have water coming out of their sink they can drink, and that attitude is the reason we have this problem.

Images:

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Figure 1. The two chambers in the battery, separated by the membrane. This is before the sodium ions move chambers.

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Figure 2. Salty water on the left and fresh water on the right after the ions moved.

URL: http://www.sciencedaily.com/releases/2016/02/160204175630.htm

 

References:

Johnson Dexter. Nanotechnology used to create a “Desalination Battery”. http://spectrum.ieee.org/nanoclast/semiconductors/nanotechnology/nanotechnology-used-to-create-a-desalination-battery. 2012.

Kyle C. Smith, Rylan Dmello. Na-Ion Desalination (NID) Enabled by Na-Blocking Membranes and Symmetric Na-Intercalation: Porous-Electrode Modeling. Journal of the Electrochemical Society, 2016; 163 (3): A530 DOI: 10.1149/2.0761603jes

Pascual Katrina. Battery Technology Could Transform Seawater to Freshwater (http://www.techtimes.com/articles/131232/20160206/battery-technology-could-transform-seawater-to-freshwater.htm.   2016

Phillip W. Elimelech M. The Future of Seawater Desalination: Energy, Technology and the Environment. http://science.sciencemag.org/content/333/6043/712.article-info.2011

Mohamed E et al. Desalination. A direct coupled photovoltaic seawater reverse osmosis desalination system toward battery based systems-a technical and economical experimental comparative study. http://www.sciencedirect.com/science/article/pii/S0011916407006741. 2008

University of Illinois at Urbana-Champaign. (2016, February 4). Battery technology could charge up water desalination. ScienceDaily. Retrieved February 12, 2016 from http://www.sciencedaily.com/releases/2016/02/160204175630.htm

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