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From seawater to drinking water, with the push of a button

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Re: From seawater to drinking water, with the push of a button

#41
post #33

I recall similar in function devices already existed for military use - except they made water from air, which is even more available than seawater: https://www.honeywell.com/us/en/press/2021/05/honeywell-led-... https://edition.cnn.com/2014/04/24/tech/innovation/machine-m...

Fun fact, there's vodka made from San Francisco fog: https://time.com/4317269/fog-vodka-san-francisco-hangar-one/

Re: From seawater to drinking water, with the push of a button

#42

Those specifications are much worse than 30 year old PUR-06. It makes one liter per hour with 20 Watts and fits in your pocket. I tried solar panel and windshield wiper motor. But direct-drive windmill was much better as wind blows 24/7 on Baja. https://youtu.be/9xYXWISWv5I?t=390 Durability was the issue. I destroyed three units and average was 200 days / 1000 liters, because all-plastic construction. Found no limits…

I was planning to make those crucial breaking parts from Carbon Fiber myself, but I was such a poster-boy for PUR that they sended me free PUR-35 ($5000). It makes 3 liters per hour and if you replace the solid-iron pumping shaft it weighs about a kilo.

Except one crucial high-pressure valve cannot be made of plastic. I made better one from fiber glass. Thereafter it been running ok for 20 years.

Re: From seawater to drinking water, with the push of a button

#44

Edit: I wrote out the comment below criticizing the efficiency of this device, when compared to reverse osmosis RO desalination (100x less efficient). However, they’re not trying to be more efficient than RO devices, they’re trying to be more compact, portable, and avoid the need for filters. They’re solving for a different problem than I was measuring them against. In my race to criticize, I overlooked those key det…

The article says they can get 1 liter for every 20 watts. So that'd give them 17,597 ounces per kWh.

Re: From seawater to drinking water, with the push of a button

#45

> The suitcase-sized device...can also be driven by a small, portable solar panel, > Yoon and Kang used machine learning to find the ideal combination of ICP and electrodialysis modules. These bits feel like they were added because ML and solar power will get more clicks.

> The research was funded ... the Experimental AI Postdoc Fellowship Program of Northeastern University, and the Roux AI Institute

That's the cause of the AI part.

The solar panel bit probably came from the Army requirements, who's another sponsor.

Re: From seawater to drinking water, with the push of a button

#46

What about filtering particles which don't have a charge like plastics or biological matter? I guess you can always just boil the water after it's been processed by the portable machine.

I didn't quite get this part either -

> The membranes repel positively or negatively charged particles — including salt molecules, bacteria, and viruses ...

Are bacteria and viruses indeed electrically charged? This sounds strange.

Re: From seawater to drinking water, with the push of a button

#47

> The suitcase-sized device...can also be driven by a small, portable solar panel, > Yoon and Kang used machine learning to find the ideal combination of ICP and electrodialysis modules. These bits feel like they were added because ML and solar power will get more clicks.

True, especially using ML to determine the size/layout of the components. That could be very easy assessed by varying the sizes in a consistent, linear way, and measuring the effectiveness in subsequent tests, rather than throwing it into the black box of ML.

Re: From seawater to drinking water, with the push of a button

#48
post #46

What about filtering particles which don't have a charge like plastics or biological matter? I guess you can always just boil the water after it's been processed by the portable machine.

I didn't quite get this part either - > The membranes repel positively or negatively charged particles — including salt molecules, bacteria, and viruses ... Are bacteria and viruses indeed electrically charged? This sounds strange.

Yes [0], "Bacterial cell surfaces possess net negative electrostatic charge by virtue of ionized phosphoryl and carboxylate substituents on outer cell envelope macromolecules which are exposed to the extracellular environment."

[0] https://doi.org/10.1016/S0167-7012(00)00224-4

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