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In this paper, novel UiO‐66‐AO‐based adsorption‐filtration hybrid membranes (UAMs) are prepared via an irradiation‐mediated growth strategy to simultaneously improve water flux and accelerate uranium extraction from water resources. The UAM shows an equilibrium adsorption that is four times faster than UiO‐66‐AO powder and an adsorption capacity that is over two times higher. UAM also achieves a record synergy of high flux and high uranium removal ratio from simulated seawater (1358.8 L m−2 h−1, 84.5%) by one‐time filtration under ambient temperature and pressure (the adsorption is 1.83 mg g−1 in 90 min). The excellent uranium extraction performance is attributed to the unique UAM structure, in which water flows through the channels of thin metal‐organic framework (MOF) film without blocking by substrate leading to the high flux during filtration, and the full contact of uranium with abundant exposed active sites promotes the adsorption. This work will be conducive to overcoming the bottleneck problems of uranium extraction from water resources. [ABSTRACT FROM AUTHOR]

Chitosan microspheres(HTCC) were prepared by hydrothermal method,and Amino-modified chitosan adsorbent (AHTCC) was prepared by epoxidization and amination method to adsorb low concentration uranium in wastewater. The structure, composition and thermal stability of AHTCC were characterized by infrared spectrometer, elemental analyzer and thermogravimetric analyzer, and the adsorption and desorption properties of AHTCC for uranium were investigated. The results show that AHTCC has a good adsorption effect on uranium in solution at pH=5~8. Under the condition of equilibrium mass concentration of uranium adsorption of 120 mg/L,the adsorption capacity reaches the 151. 6 mg/g. Its adsorption rate is faster in the initial 60 min and reaches equilibrium at 180 min. Using 80 g/L Na2CO3+20 g/L NaHCO3 as the desorption agent, the desorption rate of uranium is 97. 5%. For real uranium containing wastewater with high concentration of impurities, the removal rate of uranium can reach 95. 6% after single adsorption by AHTCC. [ABSTRACT FROM AUTHOR]

[Display omitted] • The TETA-PAO/GF electrode material was prepared by a simple and green method. • The TETA-PAO/GF electrode material exhibits excellent electrocatalytic reduction of U(VI) under electric field conditions. • The TETA-PAO/GF electrode material has good selectivity and reusability. • The TETA-PAO/GF electrode material can electrocatalytically reduce U(VI) in real seawater under electric field conditions. The amidoxime-based material is one of the effective materials for adsorbing uranium. The electrocatalysis can be used as an effective strategy for separating uranium. In this study, conductive graphite felt was used as substrate, amine-amidoxime modified polyacrylonitrile (PAN) graphite felt was prepared by heterogeneous method. With the successful synthesis of the material with bifunctional groups, the bifunctional modified PAN graphite felt (TETA-PAO/GF) had good uranium adsorption performance by the way of electrocatalysis technology. It was characterized by SEM, FT-IR, XPS, XRD, ICP-MS, etc. The adsorption capacity of the electrode material to uranium reached 1 142 mgU·g−1 in unsaturated state in 1 000 mg·L-1 spiked seawater. In real seawater adsorption experiment, 90.08 % uranium was extracted from 16 L seawater. Ultimately, the assessment of the reusability and ion selectivity of TETA-PAO/GF revealed that it has a certain use value for uranium extraction from seawater. [ABSTRACT FROM AUTHOR]

• Hemp fiber with optimal adsorption capacity and optimal fouling resistance of amidoxime-quaternized polyethyleneimine (HFAO-QPEI) were prepared using simple fiber surface modification grafting. • HFAO-QPEI exhibits excellent uranium selectivity and recyclability. • Quaternization gives HFAO-QPEI significant biofouling resistance, especially inhibiting the adhesion of mussels. • DFT calculation results indicate that the HFAO-QPEI-U mode exhibits the most stable structure. Nuclear energy plays a key role in the global energy supply. The adsorption and extraction of uranium from seawater is key to the rapid development of nuclear energy. In this paper, quaternary aminated polyethyleneimine/amidoxime-modified hemp fiber (HFAO-QPEI) with high adsorption capacity and anti-biofouling properties were successfully synthesized by immersion and hydrothermal methods. Upon systematic evaluation, HFAO-QPEI possessed high adsorption capacity and good reusability with fast adsorption kinetics, as well as good adsorption selectivity and affinity for uranyl ions. Furthermore, HFAO-QPEI not only reached a maximum adsorption capacity of 364.7 mg/g but also demonstrated a short adsorption equilibrium time of 200 min. In contrast, HFAO-QPEI demonstrated high selectivity for uranyl ions, removing up to 95.1 % of uranium with K d value of 4.69 × 104 mL/g, which was 256.3 times greater than that of hemp fiber (HF). After the fifth adsorption–desorption cycle, the recovery of U(VI) was 91.38 %. DFT calculations proved that HFAO-QPEI-U was the most stable model. The quaternary ammonium salt functionalization not only makes HFAO-QPEI have excellent anti-biofouling ability (anti-diatom rate up to 87.22 %, anti-bacterial rate up to 97 % or more, anti-adhesion of large fouling organisms mussels with a certain effect), but also modifies its surface charge, making it more suitable for the marine environment. In addition, HFAO-QPEI showed a high adsorption capacity of 2.45 mg/g in natural seawater. The results suggest that the HFAO-QPEI adsorbent holds great promise for extracting uranium from seawater. [ABSTRACT FROM AUTHOR]

• PDA and PEI co-deposition combined with electrostatic self-assembly realizes mild surface modification. • The membrane with 3 functional layers exhibits the best adsorption performance (adsorption capacity = 142.25 mg·g−1). • This membrane can achieve over 90 % uranium removal within 90 min in dynamic filtration. • DFT calculation results indicate that the PEI/PA-U mode exhibits the most stable structure. Developing simple and efficient new strategies for uranium extraction from seawater (UES) is crucial for addressing the energy crisis. Here, we proposed a mild strategy to prepare a layer-by-layer assembly membrane (LAM) by polydopamine (PDA) and polyethyleneimine (PEI) co-deposition coupled with polyethyleneimine/phytic acid self-assembly for efficient uranium extraction. By regulating the number of self-assemblies, the performance of the membrane could be easily adjusted. The functional coating's rich active groups (–NH 2 , -PO 4 3-, –OH) provided a good adsorption performance for the modified membrane, with a static adsorption capacity of 142.25 mg·g−1. Meanwhile, it possessed excellent dynamic removal rate, which could achieve over 90 % uranium removal within 90 min. The LAM also exhibited exceptional adsorption selectivity, boasting a remarkable 9:1 ratio in extracting uranium and vanadium. Furthermore, the strong adhesion of PDA endowed the material with good stability, and the adsorption capacity only decreased by 23 % after 5 cycles. DFT calculations proved that PEI/PA-U was the most stable model. Particularly, the adsorption capacity of LAM in natural seawater can reach 0.99 mg·g−1. With the simple and mild preparation process, along with the excellent adsorption performance, the LAM membrane holds great promise for seawater uranium enrichment. [ABSTRACT FROM AUTHOR]

Crystalline porous covalent frameworks (COFs) have been considered as a platform for uranium extraction from seawater and nuclear waste. However, the role of rigid skeleton and atomically precise structures of COFs is often ignored in the design of defined binding configuration. Here, a COF with an optimized relative position of two bidentate ligands realizes full potential in uranium extraction. Compared with the para-chelating groups, the optimized ortho-chelating groups with oriented adjacent phenolic hydroxyl groups on the rigid skeleton endow an additional uranyl binding site, thereby increasing the total number of binding sites up to 150%. Experimental and theoretical results indicate that the uranyl capture is greatly improved via the energetically favored multi-site configuration and the adsorption capacity reaches up to 640 mg g−1, which exceeds that of most reported COF-based adsorbents with chemical coordination mechanism in uranium aqueous solution. This ligand engineering strategy can efficiently advance the fundamental understanding of designing the sorbent systems for extraction and remediation technology. [Display omitted] • The COFs were used as bio-inspired folded scaffold structure to regulate the configuration of chelating groups. • The COFs with different configurations were synthesized by introducing isomeric building units. • The optimized configuration provides more UO 2 2+ binding sites without redundant chelating groups introduced. • 2,3-DhaTat-COF achieved high uranium adsorption capacity of 640 mg∙g−1 and short adsorption equilibrium time. • Selectivity for capturing uranium from nuclear wastewater and seawater. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hydrogel synthesized with supermacroporous structure for uranium adsorption. • The hydrogel exhibits high hydrophilicity, mechanical strength, and anti-bacteria. • The hydrogel could obtain 12.95 mg g−1 of uranium in seawater. • Zwitterions have a synergistic effect in uranium adsorption. Carboxymethylcellulose-based zwitterionic cryogels (AO-PAM/CMC) with a supermacroporous pore structure were prepared through cryo-polymerization and post-modification strategies. The hydrogel exhibited a supermacroporous structure, excellent hydrophilicity, superior mechanical properties, and resistance to biological contamination. Through a comprehensive investigation of the U(VI) adsorption process, it was observed that the AO-PAM/CMC hydrogel was predominantly characterized by chemisorption, wherein uranyl ions were adsorbed on the surface in the form of a monolayer. Under the conditions of 45 °C and pH = 5.0, the hydrogel demonstrated remarkable adsorption performance, with the maximum adsorption capacity reaching 1223.6 mg∙g−1, showcasing a high degree of selectivity for U(VI). In real seawater, the hydrogel's adsorption capacity for uranium reached 12.95 mg∙g−1 after 25 days of exposure, with the adsorption equilibrium being essentially reached in about 10 days. The adsorption mechanism of U(VI) by the hydrogel was confirmed through XPS spectroscopy and DFT calculations. The synergistic interplay between guanidino and zwitterionic moieties within the AO-PAM/CMC hydrogel enhanced U(VI) adsorption capacity and facilitated rapid uranium extraction from seawater. (UES). Therefore, the AO-PAM/CMC hydrogel presents a novel solution to address the inefficiencies of existing technologies for uranium extraction from seawater, contributing an innovative approach to the sustain-able development of nuclear energy. [ABSTRACT FROM AUTHOR]

A low-energy, ambient pressure drying strategy using synergistic cryo-polymerization and melting-crosslinking creates durable, high-strength hierarchical porous aerogels for ultrafast uranium uptake from seawater, achieving 11.89 mg g−1 within 20 days. Dual crosslinking maintains structural integrity and resists seawater-induced swelling and shrinkage, overcoming traditional aerogel fabrication challenges. [Display omitted] • Innovative dual-crosslinked aerogel with high mechanical strength and stability. • 99% ultra-connected pore volume facilitates seawater transport. • Ambient pressure drying strategy reduces energy consumption in aerogel fabrication. • Imidazole cations and amidoxime groups provide antibacterial and adsorption sites. • Achieved uranium adsorption capacity of 11.89 mg g−1 within 20 days in seawater. Continuous porous aerogels are promising materials for rapid and large-scale uranium extraction from seawater. However, their fabrication faces challenges regarding precise structural control, high mechanical strength, resistance to seawater-induced swelling and shrinkage, and the high energy consumption associated with sustained low-temperature and vacuum pumping. Inspired by plant pore structures, an ambient pressure drying strategy combining cryo-polymerization with a "melting-crosslinking" process is proposed for the large-scale fabrication of aerogels designed for ultrafast uranium uptake from seawater. The aerogel is formed by the chemical crosslinking of imidazole cationic monomers copolymerized with amidoxime, and physical crosslinking with cellulose acetate, creating a dual crosslinking structure. This dual crosslinking structure imparts high mechanical strength and resistance to seawater-induced swelling and shrinkage, maintaining structural integrity even after 10 drying cycles. The incorporation of antibacterial components enables long-term operation in seawater. The hierarchical structure, with over 99 % ultra-connected channel volume, enhances uranium adsorption, achieving an ultrafast uptake of 11.89 mg g−1 within 20 days. This work presents a new low-energy shaping strategy for aerogels used in seawater uranium extraction, with potential applications in other fields requiring high-strength aerogels with hierarchical structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • A π-electron conjugation system was designed on natural bamboo strips. • oBS-AO with superhydrophilic, antibacterial, and macroscopically programmable properties. • The π-electron conjugated system can improve the adsorption performance of uranium. • The double bridging effect of hydrogen bond can stabilize the coordination structure. Commencing with the goal of establishing a more stable coordination structure for uranium, our approach drew inspiration from the alternating single and double bonds found in benzene rings and amidoxime groups. A uranium adsorption material featuring a π-electron conjugated system is devised. This system is designed by grafting 2-cyanobenzaldehyde, 3-cyanobenzaldehyde, and 4-cyanobenzaldehyde onto bamboo strips (BS) via aldol condensation and hydrolysis reactions, resulting in the creation of 2-amidoxime phenyl BS (oBS-AO), 3-amidoxime phenyl BS (mBS-AO), and 4-amidoxime phenyl BS (pBS-AO). Among these, oBS-AO exhibits not only the highest uranium adsorption performance (224.6 mg g−1 at pH = 6 and 1.3 mg g−1 in artificial simulated seawater) but also features the most robust π-electron conjugated system, as confirmed by computational and simulation data. Notably, the uranium adsorption capacity of mBS-AO is approximately 46.7 times that of vanadium in ion competition experiments simulating seawater conditions. To delve further into the adsorption mechanism, the role of electrostatic interactions and optimized simulated coordination structures is explored. It becomes evident that the primary adsorption mechanism relies on the formation of a pentacoordination structure, and the stability of this coordination structure iss directly influenced by the strength of the π-electron conjugated system. Furthermore, the double bridging effect of hydrogen bonds serves to further stabilize the coordination structure, facilitating the specific and selective adsorption of uranium. [ABSTRACT FROM AUTHOR]

• Controllable and stable physical hydrogel based on chitosan was prepared. • Compositing of polyacrylate improved the swelling and adsorption properties. • Graphene oxide enhanced mechanical and adsorption properties of the hydrogel. • The products showed properties of adjustable polyampholyte hydrogel. • The composite hydrogel could simultaneously adsorb cationic and anionic dye. In the current study, a novel CTS/PAA/GO composite polyampholyte physical hydrogel was prepared by the SD-A-SGT method to achieve desired adsorption properties for printing and dyeing wastewater treatment. The hydrogels exhibited controllable and stable structure. The linear PAA significantly improved the swelling and adsorption properties of the hydrogel, and the composition of GO enhanced its mechanical and adsorption properties. The batch adsorption experiments revealed the ability to simultaneously absorb the cationic model dye, MB, and anionic model dye, FY3, with the similar equilibrium adsorption capacities of 296.5±31.7 mg·g−1 and 280.3±23.9 mg·g−1, respectively. The factors affecting the dye adsorption performance, including the hydrogel composition, initial dye concentration and dye solution pH, were investigated. The dye adsorption kinetics was studied and the adsorption mechanisms were proposed. The unique structure and properties of the hydrogel make it a great candidate adsorbent for wastewater treatments. [ABSTRACT FROM AUTHOR]