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Although diverse uranium (U) adsorbents have been explored, it is still a great challenge for high-efficient uranium extraction form seawater. Herein a wood-mimetic oriented porous Ti3C2Tx-MXene/gelatin hydrogel (MGH) has been explored through growing directional ice crystals cooled by liquid nitrogen and subsequently forming pores by freeze-dry (Ice-template) method, for ultrafast and high-efficient U-adsorption from seawater with great enhancement by both electric field and sunlight. Different from disperse Ti3C2Tx-MXene powder, this MGH not only can be easily utilized but also can own ultrahigh specific surface area for high-efficient U-adsorption. The U-adsorbing capacity of this MGH (10 mg) can reach 4.17 mg·g−1 after only 1 week in 100 kg of seawater, which is outstanding in existing adsorbents. Furthermore, on the positive pole of 0.4 V direct current source or under 1-sun irradiation, the U-adsorbing capacity of the MGH can increase by 57.11% and 13.57%, respectively. Most importantly, the U-adsorption of this hydrogel can be greatly enhanced by simultaneously using the above two methods, which can increase the U-adsorbing capacity by 79.95% reaching 7.51 mg·g−1. This work provides a new biomimetic porous MXene-based hydrogel for electric field/sunlight bi-enhanced high-efficient U-extraction from seawater, which will inspire new strategy to design novel U-adsorbents and systems.

Although metal–organic frameworks (MOFs) own excellent uranium adsorption capacity but are still difficult to conveniently extract uranium from seawater due to the discrete powder state. In this study, a new MOF-based macroporous membrane has been explored, which can high-efficiently extract uranium through continuously filtering seawater. Through modifying the UiO-66 with poly(amidoxime) (PAO), it can disperse well in a N,N-dimethylformamide solution of graphene oxide and cotton fibers. Then, the as-prepared super-hydrophilic MOF-based macroporous membrane can be fabricated after simple suction filtration. Compared with nonmodified MOFs, this UiO-66@PAO can be dispersed uniformly in the membrane because it can stabilize well in the solution, which have largely enhanced uranium adsorbing capacity owing to the modified PAO. Last but not least, different from powder MOFs, this UiO-66@PAO membrane provides the convenient and continuously uranium adsorbing process. As a consequence, the uranium extraction capacity of this membrane can reach 579 mg·g−1 in 32 ppm U-added simulated seawater for only 24 h. Most importantly, this UiO-66@PAO membrane (100 mg) can remove 80.6% uranyl ions from 5 L seawater after 50 filtering cycles. This study provides a universal method to design and fabricate a new MOF-based adsorbent for high-efficient uranium recovery from seawater.

Uranium extraction from seawater has attracted worldwide attention due to the massive reserves of uranium. Due to the straightforward synthesis and strong affinity toward uranyl ions (UO22+), the amidoxime group shows promise for use in highly efficient uranium capture. However, the low mass transfer efficiency within traditional amidoxime‐based adsorbents severely limits the adsorption rate and the utilization of adsorption sites. In this work, a macroporous polyamidoxime (PAO) hydrogel is prepared by yeast‐based biological foaming combined with ice crystal dispersion that effectively maintained the yeast activity. The yeast‐raised PAO (Y‐PAO) adsorbent has numerous bubble‐like holes with an average pore diameter >100 µm. These macropores connected with the intrinsic micropores of PAO to construct efficient diffusion channels for UO22+ provided fast mass transporting channels, leading to the sufficient exposure of hidden binding sites. The maximum adsorption capacity of Y‐PAO membrane reached 10.07 mg‐U/g‐ads, ≈1.54 times higher than that of the control sample. It took only eight days for Y‐PAO to reach the saturation adsorption capacity of the control PAO (6.47 mg‐U/g‐ads, 28 days). Meanwhile, Y‐PAO possessed excellent ion selectivity, good reusability, and low cost. Overall, the Y‐PAO membrane is a highly promising adsorbent for use in industrial‐scale uranium extraction from seawater. [ABSTRACT FROM AUTHOR]

Nuclear accidents and the improper disposal of nuclear wastes have led to serious environmental radioactive pollutions. The rational design of adsorbents for the highly efficient separation of strontium(II) is essential in treating nuclear waste and recovering radioactive strontium resources. Metal–organic frameworks (MOFs) are potential materials for the separation of aqueous metal ions owing to their designable structure and tunable functionality. Herein, a novel 3D MOF material MOF‐18Cr6, in which 1D channels are formed using 18‐crown‐6‐ether‐containing ligands as channel walls, is fabricated for strontium(II) separation. In contrast to traditional MOFs designed by grafting functional groups in the framework pores, MOF‐18Cr6 possesses regular 18‐crown‐6‐ether cavities on the channel walls, which not only can transport and intake strontium(II) via the channels, but also prevent blockage of the channels after the binding of strontium(II). Consequently, the functional sites are fully utilized to achieve a high strontium(II) removal rate of 99.73 % in simulated nuclear wastewater. This study fabricates a highly promising adsorbent for the separation of aqueous radioactive strontium(II), and more importantly, can provide a new strategy for the rational design of high‐performance MOF adsorbents for separating target substances from complex aqueous environments. [ABSTRACT FROM AUTHOR]

The modified waterborne acrylic resin was synthesized successfully by emulsion polymerization with octafluoropentyl methacrylate and phosphate functional monomer as monomers, showing an improved anti‐corrosion performance of the resin coating. The existence and general distribution of the elements of the modified monomer in the emulsion were explored, and the anti‐corrosion mechanism was disclosed. The results show that the modification of octafluoropentyl methacrylate and phosphate functional monomers improved the water resistance, corrosion resistance and thermal stability of acrylic resins. Compared with unmodified acrylic resin, the contact angle of the modified resin was increased from 74.23° to 83.51°, and the initial decomposition temperature was increased from 264 to 305 °C. At the same time, the corrosion voltage of the modified resin was increased, the corrosion current density was decreased, and the salt spray resistance was improved. This study provides a new way for the preparation of environmentally friendly, stable, and corrosion‐resistant waterborne acrylic resins. [ABSTRACT FROM AUTHOR]