He patented this five years ago.[1] Here's the 2015 paper.[2]
Flow rates are very, very low. Note the reference to the fluid source being a "Harvard Apparatus Syringe Pump".[3] That's just a motorized device for very slowly pressing the plunger on a syringe, for very low flow rates. If they're using that after five years of work, the process is still limited to very low flow rates.
This is not necessarily a killer limitation. Reverse osmosis started that way, but has been scaled up to industrial scale. But the technology is not here yet.
Initially at least, this process would not be competitive with methods such as reverse osmosis for large-scale seawater desalination. But it could find other uses in the cleanup of contaminated water, Schlumpberger says.
But it could help to make portable desalination modules:
Unlike some other approaches to desalination, he adds, this one requires little infrastructure, so it might be useful for portable systems for use in remote locations, or for emergencies where water supplies are disrupted by storms or earthquakes.
MIT's PR is more amazing than their research. How many science and technology programs are there in U.S. universities, all of them producing new discoveries? How about universities outside the U.S.?
The rate and impact of discoveries vary by school, yet it seems like half the discoveries I read about come from MIT, and often via links directly to MIT press releases (i.e., not to coverage in the news). MIT is a great school, but they can't be that great.
Whenever I see one of these MIT press releases, I know to take it with a giant grain of salt. I wonder if HN will eventually start penalizing links from them as low quality.
Does anyone know why forward osmosis (e.g. https://www.youtube.com/watch?v=R63zYZZuRvQ) hasn't taken off yet? It seems like it has the biggest potential to do desalination at an extremely low cost energy-wise.
Sure, if you don't account for the energy needed to form the high-energy carbon and nitrogen compounds ("special salts") in the first place. In practice the "special salts" are either a very low efficiency fossil fuel (if you dig them out of the ground) or a really roundabout and inefficient way to spend other forms of energy.
The Haber process reduces N2 and plants reduce CO2, giving you the "special salts" (energy inputs: H2 and pump pressure for Haber, sunlight for plants). Then you burn the high-energy nitrogen+carbon compounds back into N2, H2O, and CO2 to remove them from the "forward-osmosis" solution. The sunlight, H2, and mechanical work used to create the special salts could almost certainly be used more effectively to generate electricity for reverse osmosis or distillation.
But in the video I shared, it's claimed that the fancy salts can be entirely reused, and that extracting them takes relatively little energy. Thus their ongoing energy impact, and the longer-term impact of their initial cost should be relatively low, no?
In this 170 first SED prototype, the impressive salt removal and water recovery come with significant energy costs, in the range of 10−1 to 103 kWh/m3 171 (hydraulic pumping makes up about 0.5 kWh/m3 172 )
Flow rates are very, very low. Note the reference to the fluid source being a "Harvard Apparatus Syringe Pump".[3] That's just a motorized device for very slowly pressing the plunger on a syringe, for very low flow rates. If they're using that after five years of work, the process is still limited to very low flow rates.
This is not necessarily a killer limitation. Reverse osmosis started that way, but has been scaled up to industrial scale. But the technology is not here yet.
[1] http://www.google.com/patents/US8801910 [2] http://web.mit.edu/bazant/www/papers/pdf/Schlumberger_2015_s... [3] https://www.harvardapparatus.com/webapp/wcs/stores/servlet/h...