Friday, April 27, 2012

Technology Spotlight: Aquaporin

We live on the blue planet, yet only 1% of the 'blue gold' is available to the 7+ billion people.

We all think desalination is the solution to our impending water problems. If we can somehow take the 97.5% of salt water and cost effectively desalt it, we will have enough water for everyone! But, this comes at a cost. The current technologies for desalination are expensive, not only in capital, i.e. to build treatment plants, but also require a lot of energy to operate. The most common desalination technology is reverse osmosis (RO), where we push water against a very thin membrane with tiny holes. (Think kidneys) These holes allow only water molecules to go through and leaves behind the salt (concentrate / brine). To push water against the membrane requires high pressure and hence is very energy intensive. However, it is interesting to note that the energy requirement for RO desalinated water has reduced by half over the last decade. This is primarily because membrane manufacturers have designed better performing membranes. The technology is about 65% efficient at this stage. It will be foolish to expect that we can achieve 100% efficiency in the next decade, as you can never get 100% efficiency in any technology. However, it is reasonable that we will be slowly edging towards 70-75% efficiency. Moore's Law will not apply to this technology, and further 'fine-tuning' of this technology will  yield diminishing returns.

So where is the innovation? Can we reduce the need for pressure all together? A Danish company is using biomimicry and embedding proteins in membranes that can regulate the flow of water. Ever wonder how mangroves grow in brackish water? How do they filter out the salts and absorb water? The protein is called aquaporin and it sits within cell membranes. In 2003, Dr. Peter Agre was awarded the Nobel Prize in Chemistry (which he shared with Dr. Roderick MacKinnon) for his discovery of aquaporins. These proteins are also in our red blood cells, kidneys, eye lenses, almost anywhere there is water transfer across membranes. The company, Aquaporin A/S, is currently working on developing membranes that will desalinate water by a very different mechanism from the current traditional RO methods, and possibly with smaller energy footprint.

This technology is still in development phase but shows great promise. The initial trials with NASA have proven quite successful. We wish Aquaporin A/S success in their endeavors, and look forward to their product in the market in the near future.

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