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Getting Better This Year

Even through times of turmoil, the vast majority of people continue to work and build for a better cleaner future.

You might recall this blog post recently, highlighting progress in nuclear fusion. Some people think it will never be achieved, yet scientists are closer than ever. Progress continues.

There is a lot of good news with renewable energy as well. Current renewables will never be able to supplant fossil fuels, but they get cheaper, more innovative, and more efficient every year.

Many people are worried about water security in the future. If the planet warms and the population expands, then fresh water could end up in short supply at times in some parts of the world. Thankfully, scientists and engineers are hard at work to increase water desalination efforts. The most recent development comes from Columbia Engineering. They have developed a new more efficient desalination method that does not leave a salty brine as a byproduct. It also uses less energy and doesn't use a membrane. Most current desalination methods rely on reverse osmosis through a membrane (like a sieve). These membranes tend to get clogged and/or wear out after a few cycles.

The Columbia team uses a solvent to help get the salt out of the water - or in this case - to get the water out of the salt. It is termed a "temperature swing solvent extraction" (TSSE). The idea behind this method is to have zero liquid emission after desalination. Current state-of-the art desalination methods leave a highly salty liquid brine as a by-product. This is difficult to dispose of. The Columbia Engineering method only leaves dry salty by-products behind.

So how does it work? They let the salty brine mix with a solvent at a relatively cool temperature (around 5 C). The solvent soaks up the water (kind-of like a sponge) while the salt precipitates out as a solid. The solvent with the water is then separated from the salts (the salt sinks while the water containing solvent floats above. The solvent-water mixture is then heated to around 70 C, which forces the water out of the solvent (like squeezing a sponge). The solvent floats on top and is separated from the water.

This process is more efficient than other methods and it has worked in small scale demonstrations. If it can be scaled up then maybe the world will have plenty of water security in the future.

Justin Loew

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