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Highlights from the article: Uranium Extraction: A Marine-Inspired Hybrid Sponge for Highly Efficient Uranium Extraction from Seawater (Adv. Funct. Keywords: alginate; amidoxime; marine sponges; melamine sponge; uranium extraction Alginate, marine sponges, amidoxime, uranium extraction, melamine sponge.

Marine sponges are used as biomonitors of heavy metals contamination in coastal environment as they process large amounts of water and have a high capacity for accumulating heavy metals. Here, inspired by the unique physical and physiological features of marine sponges, a surface engineered synthetic sponge for the highly efficient harvesting of uranium from natural seawater is developed. An ultrathin poly(imide dioxime) (PIDO)/alginate (Alg) interpenetrating polymer network hydrogel layer is uniformly wrapped around the skeleton of a melamine sponge (MS) substrate through a simple dipping–drying–crosslinking process, providing the hybrid MS@PIDO/Alg sponge with excellent uranium adsorption performance and sufficient mechanical strength to withstand the harsh conditions of practical applications. The maximum adsorption capacity reaches 910.98 mg‐U g‐gel‐1 for the PIDO/Alg hydrogel layer and 291.51 mg‐U g‐sponge‐1 for the whole hybrid MS@PIDO/Alg sponge in uranium‐spiked natural seawater. The adsorption capacity measured after 56 d of exposure in 5 tons of natural seawater is evaluated to be 5.84 mg‐U g‐gel‐1 (1.87 mg‐U g‐sponge‐1). This novel approach shows great promise for the mass production of high‐performance sponge adsorbent for uranium recovery from natural seawater and nuclear waste. [ABSTRACT FROM AUTHOR]

Highly efficient recovery of uranium from seawater is of great concern because of the growing demand for nuclear energy. The use of amidoxime‐based polymeric fiber adsorbents is considered to be a promising approach because of their relatively high specificity and affinity to uranyl. The surface area, hydrophility, and surface charge of the adsorbent are reported to be critical factors that influence uranium recovery efficiency. Here, a porous amidoxime‐based nanofiber adsorbent (SMON–PAO) that exhibits the highest uranium recovery capacity among the existing fiber adsorbents both in 8 ppm uranium spiked seawater (1089.36 ± 64.31 mg‐U per g‐Ads) and in natural seawater (9.59 ± 0.64 mg‐U per g‐Ads) is prepared by blow spinning. These nanofibers are obtained by compositing polyacrylamidoxime with montmorillonite and exhibit the increased surface area and more exposed functional amidoxime moieties for uranyl adsorption. The residual montmorillonite enhances the hydrophility and reduces the negative surface charge, thereby increasing the contact of the adsorbent with seawater and reducing the charge repulsion between negative amidoxime group and negative uranyl species ([UO2(CO3)3]4−). The finding of this study indicates that rational design of uranium recovery adsorbents by comprehensive utilizing the key factors that influence uranium recovery performance is a promising approach for developing economically feasible uranium recovery materials. A porous amidoxime‐based nanofiber adsorbent (SMON–PAO) is rationally designed to achieve high uranium recovery capacity from seawater and fabricated by blow spinning. This finding indicates that design of uranium recovery adsorbents by comprehensively utilizing the factors that influence uranium recovery performance, which are surface area, hydrophility, and surface charge, is a promising approach for developing economically feasible uranium recovery adsorbents. [ABSTRACT FROM AUTHOR]