People have been working on uranium extraction from seawater, and making gradual progress, for a long time. Unfortunately, this article doesn't quantify anythin

People have been working on uranium extraction from seawater, and making gradual progress, for a long time. Unfortunately, this article doesn't quantify anything about how this improves over older efforts. Some key parameters for uranium-from-seawater absorbent materials: - How much uranium a given mass of absorbent can hold at saturation. - How fast it reaches saturation. - Selectivity for uranium -- there are many metals in seawater, and competing absorption can doom a material that does perfectly well with uranium diluted in distilled water. IIRC, calcium, iron, and vanadium are common competing elements. - The number of absorption/desorption cycles the material can endure before its performance degrades too badly. The linked article discloses none of these important facts. I did find this recent, relevant patent application from this group: https://patents.google.com/patent/US20170355621A1/en?oq=20170355621 https://patents.google.com/patent/US20170355621A1/en?oq=2017... The patent claims several advantages over previous absorbents: - Less expensive absorbent-group grafting onto the polymer (plain chemical synthesis instead of radiation-induced grafting). - Faster saturation. - Superior selectivity for uranium over vanadium. Surprisingly, the patent does not claim a particularly high U:absorbent mass ratio -- just "greater than 3.0 mg U per g of adsorbent." Higher numbers were demonstrated in the 1990s. But I suppose that a really impressive number would also be "greater than" that relatively low one. The patent fortunately also mentions other publications that contain further reports of the researchers' work: Kuo et al, "Characterization and Testing of Amidoxime-Based Adsorbent Materials to Extract Uranium from Natural Seawater." Ind Eng Chem Res 2016, 55, 4285-4293 (no public PDF) Gill et al., "The Uranium from Seawater Program at the Pacific Northwest National Laboratory: Overview of Marine Testing, Adsorbent Characterization, Adsorbent Durability, Adsorbent Toxicity, and Deployment Studies." Ind Eng Chem Res 2016, 55, 4264-4277 http://cafethorium.whoi.edu/website/publications/Gill%20et%20al%20U%20from%20seawater%20E&EC%202016.pdf http://cafethorium.whoi.edu/website/publications/Gill%20et%2... Pan et al, "Towards Understanding KOH Conditioning of Amidoxime-based Polymer Adsorbents for Sequestering Uranium from Seawater." RSC Advances 2015, 5, 100715-100721 https://www.osti.gov/pages/servlets/purl/1286877 https://www.osti.gov/pages/servlets/purl/1286877 ----------- After reading the papers cited in the patent, I'm still unsure what underlies the claim "Yarn-like material collects largest amount of uranium to date." Maybe they just mean "the largest amount collected to date with this particular material under development." That's not as exciting as I'd hoped from the headline. It looks like the U absorption capacity of this material isn't very high. Its good U absorption kinetics permit a good uranium:vanadium absorption ratio if exposure times are limited. Fully stripping absorbed vanadium is difficult, as it has been for other materials. I couldn't find any disclosure of the capacity fade over successive absoprtion-desorption cycles. The most significant improvement disclosed, IMO, is that they make this material without radiation grafting -- just chemical synthesis. The final material performance is not remarkably improved over prior efforts. Still, eliminating radiation grafting could make affordable large-scale production considerably easier.