Hydrophilic disc uses solar power to separate salt from water
newatlas.com
newatlas.com
That’s really bad from a density standpoint. You’re talking ~8,000 gallons per day per acre of land. Solar powered reverse osmosis is something like 1/500th the space.
If the can get installed costs below 1$ per square meter it might be interesting, but even just land costs are likely to be an issue.
Max recommended salt intake is less than 1 teaspoon per day. You need 2 liters of water per day. There's nearly 6 teaspoons of salt in 1 liter of sea water. That's quite a bit of excess salt. Kind of a bummer really. Wish we had a gland that got rid of excess salt then we could just drink sea water.
If such a gland existed, it would probably require a lot of energy to work. Plus, what would the gland do with all of the salt it is filtering just send it to your kidneys/bladder? I'm imagining kidney-stones formed from all the excess salt your body is trying to get rid of
The mammalian equivalent would likely be salt hairs.
It can grow in seawater, brackish water, or effluent from other agriculture or aquaculture. We should be growing more of it.
Atriplex genus are amaranths called "saltbush"; many are edible directly or usable as livestock forage. Atriplex hortensis is a leaf vegetable, like spinach, often paired with sorrel.
Tetragonia tetragonoides is "sea spinach" and has been cultivated as a leaf vegetable.
Attalea speciosa is an oil palm tree.
Anemopsis californica or "yerba mansa" is used as a medicinal herb.
Sea mammals get most of their water from the food they eat (fish, etc.), and don’t drink seawater.
No-one made any such suggestion. One person lamented that such a gland didn't exist; they did not assert its existence. The other person didn't mention glands at all.
That infers sea mammals have working salt glands.
The other commenter clearly implied 2 things:
1. sea mammals have salt glands
2. their bodies have solved the problem of removing waste salt from said glands
There's no way to interpret the commenter's statement otherwise without it being nonsensical. Sea mammals manage (what exactly) just fine?
If you can't see that, then I'm sorry, here's a simpler analogy to illustrate my point:
Me: "Pancakes can't be made without flour"
Commenter: "French chefs manage just fine"
A rational person would deduce that what Person 2 is implying is: "French chefs [are able to make pancakes without flour] just fine", not: "French chefs [are able to make pancakes] just fine"
They do supplement that with water extracted from their food. But unlike humans they are better at expelling salt. “In the seal and sea lion species, for which measurements exist, the animals' urine contains up to two and a half times more salt than seawater does and seven or eight times more salt than their blood.” Human urine on the other hand contains less salt than sea water resulting in dehydration when drinking sea water.
We've got those - they're called kidneys. Unfortunately, they can't get the output dense enough to be useful for drinking saltwater...
(Maximum saltiness of urine is less than that of saltwater, which is why drinking saltwater dehydrates you)
“Animal metabolism produces about 110 grams of water per 100 grams of fat,[1] 42 grams of water per 100 g of protein and 60 grams of water per 100 g of carbohydrate. [...] In mammals, the water produced from metabolism of protein roughly equals the amount needed to excrete the urea which is a byproduct of the metabolism of protein.[6] Birds, however, excrete uric acid and can have a net gain of water from the metabolism of protein.“
Should this type of technology scale out, some of these salt production operations might also be able to produce desalinated water either for domestic or industrial use (in the case it is still too brackish for drinking).
You now need to expend energy to gather those minerals from somewhere else and then put them in the water. Is the energy spent gathering those minerals more than other desalination processes?
Did you mean the white stuff coming out :)
There are minerals in your food. You don't need to get them all from your water. Anywhere is as good as anywhere else.
And wouldn't the minerals in food compensate for their lack in water?
It’s common to add a bit of salt and Epsom salts to water when brewing - the harder water improves the taste.
You get your minerals from food, not water. I doubt your premise about leaching body minerals by drinking distilled water (or rainwater!).
true. and if the salt produced by this process if free of micro plastics, people might pay even more
"Results of experiments in human volunteers evaluated by researchers for the WHO report (3) are in agreement with those in animal experiments and suggest the basic mechanism of the effects of water low in TDS (e.g. < 100 mg/L) on water and mineral homeostasis. Low-mineral water markedly: 1.) increased diuresis (almost by 20%, on average), body water volume, and serum sodium concentrations, 2.) decreased serum potassium concentration, and 3.) increased the elimination of sodium, potassium, chloride, calcium and magnesium ions from the body"
The university's press release at https://www.monash.edu/news/articles/water-solutions-without... says: "Researchers created a disc using super-hydrophilic filter paper with a layer of carbon nanotubes for light absorption. A cotton thread, with a 1mm diameter, acted as the water transport channel, pumping saline water to the evaporation disc. The saline water is carried up by the cotton thread from the bulk solution to the centre of the evaporation disc. The filter paper traps the pure water and pushes the remaining salt to the edges of the disc."
My best guess at what this means is that some of the water is turned into vapor (not really steam at 100 C, I guess?) and that this evaporation drives the capillary effect that keeps bringing in new water. Some other part of the water, the part that "the filter paper traps", could then drip out into the column. Maybe? Or maybe this prototype is really more about just demonstrating that salt can be collected, and doesn't care about capturing the water.
Here's the original article, paywalled at UKP 42.50: https://pubs.rsc.org/en/content/articlelanding/2019/ee/c9ee0...
is a lower tech solar solution?