Science

Burnt wood used to purify water

Burnt wood used to purify wate...
The solar steam generation testing rig that was used in the study
The solar steam generation testing rig that was used in the study
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The solar steam generation testing rig that was used in the study
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The solar steam generation testing rig that was used in the study

In some parts of the world, one of the main ways of obtaining drinking water involves using the heat of the sun to boil salty or tainted water. That process, known as "solar steam generation," may soon be made simpler and less expensive … using burnt wood.

The basic idea behind solar steam generation is that untreated water gets drawn up through a surface-located material that's heated by sunlight, to the point that the water boils. The resulting steam rises, condenses and is collected in the form of purified water, while the salt and/or contaminants are left behind.

When it comes to the material used, scientists have recently had the most success utilizing things like graphite and copper. A University of Maryland team led by Liangbing Hu, however, has achieved similar results using wood that's carbonized (burned black) on the upper surface, to help it absorb solar heat.

The best results were obtained utilizing wood that was particularly porous, such as poplar and pine. Those pores drew the water into the wood from underneath, and carried it to the surface by capillary action. Once on the solar-heated surface it boiled away, thus drawing more water up from below.

The wooden blocks used in the lab tests were about the size of the palm of a hand. That said, Hu believes that the technology could easily be scaled up for use in water treatment plants.

Wood can also be used to create quite an effective water filter, as shown by research recently conducted at MIT and Sweden's KTH Royal Institute of Technology.

A paper on the Maryland research was published this week in the journal Joule.

Source: Cell Press via EurekAlert

1 comment
Martin Hone
Ok, seeing as it gets boiled away, what is the method used to collect the evaporated water ?