Is there anything it can’t do?
“It’s 500 times thinner than the best filter on the market today and a thousand times stronger,” Stetson explained to Reuters. “The energy that’s required and the pressure that’s required to filter salt is approximately 100 times less.”
Faster, please. This would help people world wide, but we could use it in coastal CA as well.
I’ve got a reverse osmotic brain teaser.
If the old methods required about 27 atmospheres of pressure and this new material requires only 0.27 atmospheres, then the perpetual motion osmosis problem is easier to test.
And the question is this:
Put the reverse-osmosis filter at bottom end of a long pipe and submerge it in the ocean.
The pressure of the surrounding sea water goes up at 0.099197 atmospheres/meter (10,051.15 Pascals/m)
The pressure of the fresh water in the pipe goes up at 0.096777 atmospheres/meter (9,806 Pascals/m)
The difference is 0.002419 atmospheres/meter (245.15 Pascals/m)
So if the membrane starts letting water through with a pressure differential of just 0.27 atm, water starts to flow through when the pipe is lowered to 2.7 meters and then stops once a little is in the pipe (which lowers the pressure differential). By lower the pipe to 111.6 meters (0.27 atm/0.002419 atm/m) you’d have the 0.27 atm pressure differential at the bottom, while the top of the fresh water column would match up with sea level.
If you lower the pipe still further, say 1000 meters, the ocean pressure is 99.197 atmospheres, and minus the 0.27 pressure differential across the membrane, the fresh water pressure would be 98.927 atmospheres. But that would mean the fresh water column has risen to 1022 meters, or 22 meters above sea level.
So that fresh water, flowing up through the pipe, could be used to turn a turbine and provide free energy – forever – in a closed system.
My guess is that the required osmotic pressure isn’t constant, but also some function of the absolute pressure, as that would be the only easy way to rule out the impossibility of the device.
I think this pressure difference refers to the irreversible pumping loss owing to the resistance of the membrane — it does not refer to the reversible osmotic pressure of the salt concentration difference.
You are correct, darn it. Sea water’s osmotic pressure is still 27.6 atmospheres relative to fresh water, which means the pipe is back down in the Marianas Trench to work (11.4 km required).
But there’s bound to be something about osmotic pressure that precludes the construction of a perpetual motion machine, however large.
I remember they announced this a year or so ago and still nothing has happened.
Well, the link is 3 years old.
“The energy that’s required and the pressure that’s required to filter salt is approximately 100 times less.”
Faster, please. This would help people world wide…
Yes! They’d have enough salt to last forever!
“This would help people world wide…”
Yes! They would have enough salt to last forever!