Many precious metals such as Au, Ag, Li and U are important in high technology and modern industry. Earth’s mineral reserves of these metals are usually very limited or suffer from high extraction costs. Although most of these valuable metal ions are found in the ocean, the key to improving the extraction of these metals from seawater is still low cost and high efficiency adsorbents. The research group led by prof. LI Chaoxu from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT), Chinese Academy of Sciences (CAS), showed that biological nanofibrils effectively extract precious metal elements from water.
Their findings were published in ACS Nano on August 15. In recent years, the group has done a lot of research in the field of exfoliation and self-assembly of biological nanofibrils. They found that cyanoethyl substitution allows rapid exfoliation of cyanoethyl cellulose nanofibrils by mild shearing (e.g., manual shaking and homogenization) within 30 min with up to ∼90% conversion.
They recently found that cellulose fibrils are preferentially exfoliated from the lignin-poor layer of secondary cell walls of balsa wood during the in situ amidoximation process, and these fibrils fill the tracheids of wood cells.
By aligning the cellular tracheids perpendicular to the flow, the resulting forests can serve as efficient and high-pressure filtration membranes to remove aqueous uranium ions, analogous to a typical filter. Lm. -2 h-1 for a 2 mm thick free-standing membrane under a pressure of 6 bar.
“This study not only provides an in-situ method for the production of biological nanomaterials, but also provides a sustainable route for the highly efficient extraction of aqueous uranium,” said Prof. LI Mingjie, one of the study’s corresponding authors.
In their review published in Exploration on July 11, they report that functional groups (e.g., carboxyl, amino, phosphonate, and hydroxyl) in biological nanofibrils enable chemical reduction and capture of noble metal ions (e.g., Au, Ag, and Pt) from water. a green and sustainable way to recover precious metals.
