Many precious metals such as gold, silver, lithium and uranium are fundamental to high technology and modern industry. However, terrestrial mineral reserves of these metals are generally very limited or suffer from high extraction costs.
To date, since most of these precious metal ions are found in the ocean, low-cost and high-efficiency adsorbents are the key to the development of the extraction of these metals from seawater.
What are nanofibrils?
Nanofibrils are very small nanometer-sized fibers that can be made of different materials and perform different functions. They are composed of natural, non-synthetic substances, such as cellulose. Cellulose nanofibrils are, in fact, the most discussed today, as they have a number of advantages. These fibrils have a low production cost and excellent biodegradability, combined with great strength and rigidity. Furthermore, they are non-toxic substances, with a high degree of absorption when used as a base for aerogels and foams.
In addition to these unique properties, the nanocellulose can be produced in large quantities and can be easily functionalized to perform different functions due to the presence of many hydroxyl groups along the chain.
Precious metals from water: the study
Un research team led by Prof. Li Chaoxu from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences (CAS), revealed that the biological nanofibrils they made can effectively extract precious metal elements from water. The results were published in ACS Nano on August 15.
“This study not only provides an in situ approach to the production of biological nanomaterials, but also offers a sustainable route for the high-efficiency extraction of aqueous uranium,” said Prof. LI Mingjie, one of the corresponding authors of the study.
In the review published on Exploration on July 11, researchers reported that the functional groups (e.g., carboxyl, amino, phosphonate, and hydroxyl) of biological nanofibrils enabled the chemical reduction and capture of noble metal ions (e.g., gold, silver, and platinum ) from water, providing a green and sustainable route for the recovery of noble metals.
Further developments will tell us whether nanofibrils are the future of precious metal mining and whether this future can be more sustainable.
