Phosphate-Functionalized Fibrous Adsorbent for Effectively Extracting Uranium from Seawater

Abstract

Uranium is a basic and strategic resource related to national development and security. The uranium resources contained in the ocean are thousands of times that in the land, up to about 4.5 billion tons. However, it is still a severe challenge for the extraction of uranium from seawater as it contains trace amounts of uranium and a large number of cations. Herein, a new uranium extraction material, phosphate-functionalized collagen fibers, was prepared by a “covalent cross-linking” method by grafting the phosphate functional groups onto the surface of collagen fibers (CF) with a multihierarchy structure and multiple functional groups. The special structure of CF makes the adsorbent exhibit multistage kinetics and is controlled by chemisorption and layer diffusion. Through the introduction of amino and phosphoric acid functional groups, collagen fiber-alendronate sodium trihydrate (CF-AST) exhibits high-efficiency adsorption for uranium with the maximum adsorption reaching 277.78 mg g–1. In the extraction test from the East China Sea, CF-AST displayed a total uranium extraction mass of 29.61 μg after processing 10 L of seawater with an extraction rate of 89.69%. This adsorbent has shown superiorities in selectivity, kinetics, capacity, and reproducibility of uranium separation and enrichment from seawater, which is an economically viable and industrially scalable realistic uranium extraction material.

Uranium Adsorbents Based on Hypercross-Linked Asphalt Polymers via a Cyanide-Free Strategy

“…Several approaches for this purpose have been developed, including chemical precipitation, 4 ion exchange, 5 photocatalysis, 6,7 and adsorption. 8,9 In particular, adsorption is recognized as the most feasible method for its convenience, high efficiency, and low cost, which attracts more and more interest in both academic and industrial fields. To date, a variety of uranium adsorbent materials have been exploited, including active carbon, 10 porous silica, 11 covalent organic frameworks (COFs), 12 metal−organic frameworks (MOFs), 13 and porous organic polymers (POPs).…”

“…In comparison with their cousins, POPs exhibit the merits of easy postfunctionalization and robust chemical and environmental stability, giving them potential for the practical application. 15−17 To promote the absorption performance, various organic groups have been integrated onto the skeleton of the adsorbents, including imidazole, 18 phosphate, 8,19 phenolic hydroxyl, 20 amidoxime groups, 21,22 etc. Among them, amidoxime groups receive tremendous attention due to their excellent binding capacity and selectivity for uranyl ions.…”

“…To promote the absorption performance, various organic groups have been integrated onto the skeleton of the adsorbents, including imidazole, phosphate, , phenolic hydroxyl, amidoxime groups, , etc . Among them, amidoxime groups receive tremendous attention due to their excellent binding capacity and selectivity for uranyl ions .…”

“…In the processes of uranium mining and nuclear power generation, a large amount of uranium-containing wastewater is produced, inevitably causing serious environmental pollution without pretreated discharge. , Therefore, the enrichment and recovery of uranium from wastewater not only offer an alternative energy-saving approach to obtain uranium but also attach great significance to environmental protection. Several approaches for this purpose have been developed, including chemical precipitation, ion exchange, photocatalysis, , and adsorption. , In particular, adsorption is recognized as the most feasible method for its convenience, high efficiency, and low cost, which attracts more and more interest in both academic and industrial fields. To date, a variety of uranium adsorbent materials have been exploited, including active carbon, porous silica, covalent organic frameworks (COFs), metal–organic frameworks (MOFs), and porous organic polymers (POPs) .…”

Layered double hydroxide intercalated with dimethylglyoxime for highly selective and ultrafast uptake of uranium from seawater

“…4 In spite of the concentration of UO 2 2+ being extremely low (about 3–9 ppb) in natural seawater, the high total reserves of UO 2 2+ in oceans (about 4.5 billion tons) could provide nuclear power for thousands of years. 5,6 Adsorption is considered as the preferred method for extracting UO 2 2+ from aqueous environments due to its advantages of environmental friendliness, low cost, high efficiency and simple operation. 7 From what has been discussed above, the design and fabrication of highly efficient and selective uranium sorption materials from natural seawater or contaminated seawater have attracted considerable attention.…”