drwex (drwex) wrote,
drwex
drwex

We take this moment to remind ourselves that not all wrong news is "fake"

Right now there's a lot of airplay being given to a discovery in the UK of which this headline is typical: "Graphene Sieve Makes Seawater Drinkable".

Um, no. It does not. That's not even close to what happened. What actually happened is some dudes in a lab have a theoretical solution to a really serious problem. It's a very interesting solution in that it appears to show how a particular set of structures and temperature control can permit a graphene-based system to filter very small salts from a liquid without significantly impeding water flow.

But let me list a few of the problems here:

  • There's more than just salts making seawater undrinkable. Desalination is an important and necessary step, but it's not sufficient.

  • The lab dudes haven't actually desalinated any water yet, never mind doing so at scale. Mass producing the necessary graphene structures and getting them to behave in real life the way the lab model says they can behave are unsolved problems.

  • The lab dudes haven't actually tested their innovation on any messy real-world molecules. Instead, they've run "molecular dynamic simulations". In English that means they wrote some computer programs to model how they think things will behave. I happen to work with a lot of very smart chemical engineers and talked with one who did a ton of MD simulation for his PhD. He pointed out that MD simulations involve a number of simplifying assumptions, which you have to tweak to make your computer codes run. How well the result aligns with reality is something still to be seen.

  • If you read the paper (you should - it's a good paper and it's linked from that Yahoo article) you see there are also interesting discussions of the role temperature plays. In lab simulations you can get temperature to behave exactly how you want; in the real world not so much.

  • Even if all the above works out, thermodynamics still exists. AFAICT the lab work does not calculate the energy needed to manufacture and operate this system. That alone could be too high (especially if precise temperature control is needed) to make it economically feasible at scale.


This is why things take 20-30 years to go from hairy lab prototypes to actual commercial systems and this thing isn't even at "hairy lab prototype" stage, yet. If you want to see the state of the art in actual desalination it's still RO, and the Israelis put the biggest RO plant in the world online a couple years ago.

So the news stories stating that this discovery is going to lead to (more) drinkable sea water are just wrong. Not fake, but just wrong.

See also Popehat's takedown of recent political wrong news which I won't repeat here. But having two extreme examples of this sort of thing cross my news feed in one morning prompted me to write. We now return you to the ongoing shitshow...

Cross-posted from Dreamwidth, at http://drwex.dreamwidth.org/946410.html. You can comment here or there.
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