I’m referring to [this article](https://www.eurekalert.org/pub_releases/2021-06/kauo-ech060321.php) about a new method for extracting lithium from the ocean.
Please these two paragraphs from the article-
The cell contains three compartments. Seawater flows into a central feed chamber, where positive lithium ions pass through the LLTO membrane into a side compartment that contains a buffer solution and a copper cathode coated with platinum and ruthenium. Meanwhile, negative ions exit the feed chamber through a standard anion exchange membrane, passing into a third compartment containing a sodium chloride solution and a platinum-ruthenium anode.
The researchers tested the system using seawater from the Red Sea. At a voltage of 3.25V, the cell generates hydrogen gas at the cathode and chlorine gas at the anode. This drives the transport of lithium through the LLTO membrane, where it accumulates in the side-chamber. This lithium-enriched water then becomes the feedstock for four more cycles of processing, eventually reaching a concentration of more than 9,000 ppm. Adjusting the pH of this solution delivers solid lithium phosphate that contains mere traces of other metal ions — pure enough to meet battery manufacturers’ requirements.
In: Chemistry
If you pass a current through an ionized solution then any positive ions in that solution will collect on the cathode and any negative ions will collect on the anode. They’re claiming they’ve stuck a filter onto the cathode so that only lithium can collect on it. Since seawater contains trace amount of lithium, they’re claiming that they can use this filter to concentrate lithium from sea water. There is nothing revolutionary about anything in that “article”. This is very standard stuff. The problem with extracting lithium from seawater is the cost – which is astronomical – not the ability to do it in the first place.
I put article in quotations because its not a real article. Its a paid advertisement from a University in Saudi Arabia. Its not clear what the purpose of the advertisement is but typically advertisements like these are essentially solicitations for investors – usually they’re hoping investors will see this and approach them with funding to increase the scale of what they’re doing.
Extracting valuable metals from seawater is a very old, very common investment scam. The amount of stuff other than water in the ocean is extremely low and the amount of energy required to separate it out is extremely high. If what this university is claiming is true and they can economically extract lithium from seawater it would be one of the greatest advances in human history.
If that were actually the case they would be using their invention to actually extract lithium from seawater – not paying to get a press release carried on that website.
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