Uranium Recovery from Seawater Using Amidoxime-Based Braided Polymers Synthesized from Acrylic Fibers

Abstract

Global demand for nuclear energy is expected to rise in the coming decades. To meet these growing needs, new uranium resources must be explored. One of the potential alternatives to traditional uranium mining is oceanic uranium. The capture and recovery of uranium from the ocean have been under investigation for some time, with many recent studies focused on amidoxime-based adsorbents. These adsorbents, while able to achieve high uranium recovery capacities, are, nevertheless, expensive to produce and adsorb a significant amount of hard-toremove vanadium. The purpose of this study is to evaluate the adsorption performance of amidoxime-based polymer braids synthesized from acrylic fibers that are designed to significantly cut polymer synthesis and conditioning costs. Adsorption experiments were performed in a mesoscale recirculating raceway flume system at environmental conditions, approximately 10.8 °C, with 40-μm prefiltered seawater over 28 days for small-and large-sized polymer braids. For both braid sizes, the adsorption of vanadium was far lower on the acrylic adsorbent considered in the present study than on previously tested adsorbents developed at Oak Ridge National Laboratory (ORNL AF1 and AI8). The small acrylic braids also outperformed both ORNL materials with respect to uranium adsorption under similar conditions. Adsorption modeling was used to simulate the performance at higher temperatures based on 20 °C experiments previously performed with these materials. Simulation results indicated that the small acrylic braids would have a somewhat less significant advantage with respect to uranium adsorption over both ORNL AF1 and AI8 at 20 °C and will continue to outperform both ORNL adsorbents at 31 °C. Vanadium adsorption on the small acrylic braids was less than onethird of the vanadium adsorption on either AF1 or AI8 for all temperatures. This behavior indicates that the newly developed acrylic adsorbents are able to achieve superior uranium adsorption compared to other amidoxime adsorbents previously developed while being cheaper to produce and adsorbing significantly less vanadium.

A marine bacteria-inspired electrochemical regulation for continuous uranium extraction from seawater and salt lake brine

“…6 However, extracting uranium at a concentration of 3.3 μg L −1 from the hypersaline and complex marine environment is an enormous challenge. 7–11…”

Phosphate-Functionalized Fibrous Adsorbent for Effectively Extracting Uranium from Seawater

“…4,5 If the uranium in seawater can be extracted effectively, it can theoretically meet the global nuclear energy demand for thousands of years in the future. 6,7 In 2016, two scientists from the Georgia Institute of Technology in the United States published a comment in Nature, listing "Uranium Extraction from Seawater" as one of the "Seven chemical separations to change the world". 8 However, the content of uranium in seawater is extremely low (about 3.3 μg L −1 ) 9,10 and contains a large number of cations such as Na + , K + , Mg 2+ , and Ca 2+ , as well as anions such as Cl − , HCO 3 − , SO 4 2− , and Br − .…”

“…Fortunately, seawater contains a lot of uranium. It is estimated that the uranium resources contained in the ocean are thousands of times that in the land, up to about 4.5 billion tons. , If the uranium in seawater can be extracted effectively, it can theoretically meet the global nuclear energy demand for thousands of years in the future. , In 2016, two scientists from the Georgia Institute of Technology in the United States published a comment in Nature, listing “Uranium Extraction from Seawater” as one of the “Seven chemical separations to change the world” . However, the content of uranium in seawater is extremely low (about 3.3 μg L –1 ) , and contains a large number of cations such as Na + , K + , Mg 2+ , and Ca 2+ , as well as anions such as Cl – , HCO 3 – , SO 4 2– , and Br – . , , Therefore, materials for extracting uranium from seawater must have high selectivity to uranium and at the same time have cost-effectiveness similar to that of the terrestrial ore …”

Binding Study of Vanadium and Uranium Complexes with Amidoxime Ligands at different pH

“…[3][4] Amidoxime-based polymer adsorbents have been shown to be most effective material for sequestering uranium from seawater. [5][6][7][8][9][10][11][12][13][14][15][16] Vanadium is a major competing element for uranium adsorption from seawater using amidoxime-based adsorbents. [17][18][19][20] Vanadium adsorption is much greater than uranium from seawater utilizing amidoxime-based adsorbents.…”

“…The total amount of uranium present in sea water is around 4.5 billion metric tons [3–4] . Amidoxime‐based polymer adsorbents have been shown to be most effective material for sequestering uranium from seawater [5–16] . Vanadium is a major competing element for uranium adsorption from seawater using amidoxime‐based adsorbents [17–20] .…”