Regenerable Covalent Organic Frameworks for Photo‐enhanced Uranium Adsorption from Seawater

Uranium is a key resource for the development of the nuclear industry, and extracting uranium from the natural seawater is one of the most promising ways to address the shortage of uranium resources. Herein, a semiconducting covalent organic framework (named NDA‐TN‐AO) with excellent photocatalytic and photoelectric activities was synthesized. The excellent photocatalytic effect endowed NDA‐TN‐AO with a high anti‐biofouling activity by generating biotoxic reactive oxygen species and promoting photoelectrons to reduce the adsorbed U^VI to insoluble U^IV, thereby increasing the uranium extraction capacity. Owing to the photoinduced effect, the adsorption capacity of NDA‐TN‐AO to uranium in seawater reaches 6.07 mg g^?1, which is 1.33 times of that in dark. The NDA‐TN‐AO with enhanced adsorption capacity is a promising material for extracting uranium from the natural seawater.     

Ultrafast and Highly Selective Uranium Extraction from Seawater by Hydrogel‐like Spidroin‐based Protein Fiber

For the practical extraction of uranium from seawater, adsorbents with high adsorption capacity, fast equilibrium rate, high selectivity, and long service life are needed. Herein, a chimeric spidroin‐based super uranyl‐binding protein (SSUP) fiber was designed by fusing the gene of super uranyl‐binding protein (SUP) with the gene of spidroin. SUP endowed the SSUP fiber with high affinity and selectivity to uranium, and spidroin gave the SSUP fiber with high mechanical strength and high reusability. The wet SSUP fiber is a water‐rich hydrogel‐like structure, which provided abundant hydrophilic intermolecular space for the entrance of uranyl ions, and could accelerate the rate for uranium adsorption. In seawater, the SSUP fiber achieved a breakthrough uranium extraction capacity of 12.33 mg g^?1 with an ultrashort equilibration time of 3.5 days, suggesting that SSUP fiber might be a promising adsorbent for uranium extraction from the natural seawater.     

Spidroin‐Inspired,High‐Strength,Loofah‐Shaped Protein Fiber for Capturing Uranium from Seawater

The unique three‐dimensional structure of spidrion determines the outstanding mechanical properties of the spider silk fiber. Inspired by the similarity of the three‐dimensional structure of superb‐uranyl binding protein (SUP) to that of spidroin, a dual‐SUP (DSUP) chimeric protein fiber with high tensile strength is designed. The DSUP hydrogel fiber exhibits a loofah‐shape structure by the cross‐interaction of the protein nanofiber. Full exposure of abundant functional uranyl‐binding sites in the stretchable loofah‐shape hydrogel protein fiber give the DSUP fiber a groundbreaking uranium extraction capacity of 17.45 mg g^?1 with an ultrashort saturation time of 3 days in natural seawater. This work reports the design of an adsorbent with ultrahigh uranium extraction capacity and explores a strategy for fabricating artificial high‐strength functional non‐spidroin protein fiber.     

Regenerable Covalent Organic Frameworks for Photo-enhanced Uranium Adsorption from Seawater

Uranium is a key resource for the development of the nuclear industry, and extracting uranium from the natural seawater is one of the most promising ways to address the shortage of uranium resources. Herein, a semiconducting covalent organic framework (named NDA-TN-AO) with excellent photocatalytic and photoelectric activities was synthesized. The excellent photocatalytic effect endowed NDA-TN-AO with a high anti-biofouling activity by generating biotoxic reactive oxygen species and promoting photoelectrons to reduce the adsorbed U^VI to insoluble U^IV, thereby increasing the uranium extraction capacity. Owing to the photoinduced effect, the adsorption capacity of NDA-TN-AO to uranium in seawater reaches 6.07 mg g⁻¹, which is 1.33 times of that in dark. The NDA-TN-AO with enhanced adsorption capacity is a promising material for extracting uranium from the natural seawater.     

Photoinduced Multiple Effects to Enhance Uranium Extraction from Natural Seawater by Black Phosphorus Nanosheets

Based on the photoinduced photothermal, photoelectric, and photocatalytic effects of black phosphorus (BP) nanosheets, a BP‐PAO fiber with enhanced uranium extraction capacity and high antibiofouling activity is fabricated by compositing BP nanosheets into polyacrylamidoxime (PAO). The photothermal effect increases the coordination interaction between UO₂²⁺ and the functional amidoxime group, and the photoelectric effect produces the surface positive electric field that exhibits electrostatic attraction to the negative [UO₂(CO₃)₃]^4?, which all increase the capacity for uranium adsorption. The photocatalytic effect endows the adsorbent with high antibiofouling activity by producing biotoxic reactive oxygen species. Owing to these three photoinduced effects, the photoinduced BP‐PAO fiber shows a high uranium adsorption capacity of 11.76 mg g^?1, which is 1.50 times of the PAO fiber, in bacteria‐containing natural seawater.     

Constructing amidoxime-modified porous adsorbents with open architecture for cost-effective and efficient uranium extraction

The dense structure of polymeric matrices exposes only 10–20% of adsorption (amidoxime) groups, thus detracting from the extraction efficiency of uranium from seawater. Herein, the amidoxime-modified building units were cross-linked via the Scholl reaction into porous aromatic frameworks (PAFs). Due to the formation of open architecture, PAF adsorbents reveal a larger utilization ratio (>60%) of amidoxime groups. Consequently, PAF samples enable an ultrahigh uranium capacity of 702 mg g⁻¹, which creates a 16-fold capacity enhancement and gains a 7-fold adsorption rate improvement compared with polymer-based adsorbents. Notably, PAF solids are able to be integrated into various devices, thus realizing versatile and efficacious uranium extraction from real seawater (meeting the commercial standard ∼6 mg g⁻¹ in 21 days). In addition, the final cost using our PAF-based adsorbent is US $189.77 per kg uranium, it is in accordance with the prevailing market cost ($100–335 per kg).

The dense structure of polymeric matrices exposes only 10–20% of adsorption (amidoxime) groups, thus detracting from the extraction efficiency of uranium from seawater.     

An Auto‐Switchable Dual‐Mode Seawater Energy Extraction System Enabled by Metal–Organic Frameworks

Harvesting energy directly in oceans by electrochemical devices is essential for driving underwater appliances such as underwater vehicles or detectors. Owing to the extreme undersea environment, it is important but difficult to use the devices with both a high energy density and power density simultaneously. Inspired by marine organisms that have switchable energy extraction modes (aerobic respiration for long‐term living or anaerobic respiration to provide instantaneously high output power for fast movement), an auto‐switchable dual‐mode seawater energy extraction system is presented to provide high energy density and power density both by initiatively choosing different solutes in seawater as electron acceptors. With assistance from metal–organic frameworks, this device had a theoretical energy density of 3960 Wh kg^?1, and a high practical power density of 100±4 mW cm^?2 with exceptional stability and low cost, making practical applications in seawater to be possible.     

Use of metal composite MOF‐5‐Ag2O‐NPs as an adsorbent for the removal of Auramine O dye under ultrasound energy conditions

In this work, MOF‐5 composited with Ag₂O nanoparticles was prepared and characterized via X‐ray diffraction, field emission‐scanning electron microscopy, energy‐dispersive spectroscopy and FT‐IR analysis. This new material was subsequently employed for removing basic yellow dye [Auramine O (AO)] from aqueous solution under ultrasound irradiation. Several experiments were designed by central composite design in which operational parameters such as such as pH, MOF‐5‐Ag₂O mass and initial concentration of AO involved in the process were optimized. The significance of individual parameters and their possible interactions were investigated using analysis of variance (anova ). The optimum values of 6, 0.025 g and 6 mg l^?1 were obtained for the pH, MOF‐5‐Ag₂O‐NPs mass and the initial concentrations of AO, respectively, with desirability of 1.0. At such conditions, the efficiency for the removal of AO was found to be 89.45%. Various isotherm models for fitting the experimental equilibrium data were studied, and it was found that the Langmuir model has the highest efficiency for correlation of experimental equilibrium data, so that the monolayer adsorption capacity of MOF‐5‐Ag₂O for successful removal of AO was 260.70 mg g^?1 at optimal conditions.     

Hydrophobic‐Force‐Driven Removal of Organic Compounds from Water by Reduced Graphene Oxides Generated in Agarose Hydrogels

Hydrophobic reduced graphene oxides (rGOs) were generated in agarose hydrogel beads (AgarBs) by NaBH₄ reduction of graphene oxides (GOs) initially loaded in the AgarBs. The resulting rGO‐loaded AgarBs were able to effectively adsorb organic compounds in water as a result of the attractive hydrophobic force between the rGOs in the AgarBs and the organic compounds dissolved in aqueous media. The adsorption capacity of the rGOs was fairly high even toward reasonably water‐soluble organic compounds such as rhodamine B (321.7 mg g^?1) and aspirin (196.4 mg g^?1). Yet they exhibited salinity‐enhanced adsorption capacity and preferential adsorption of organic compounds with lower solubility in water. Such peculiar adsorption behavior highlights the exciting possibility for adopting an adsorption strategy, driven by hydrophobic forces, in practical wastewater treatment processes.     

On‐Line Selective Solid‐Phase Extraction of Copper with a Surface Ion Imprinted Silica Gel Sorbent

Copper(II)‐ion imprinted silica gel (Cu‐IISG) sorbent was synthesized by surface imprinting technique and was employed as a selective solid‐phase extraction material for on‐line preconcentration and separation, then coupled with atomic absorption spectrometry (AAS) determination of Cu(II). The higher selectivity coefficient of Cu‐IISG for Cu(II) in the presence of competitive ions such as Fe(III), Ni(II) and Zn(II) was above 411, which was 35 times of NISG. The static adsorption capacity and dynamic adsorption capacity were 41.11 mg g^?1 and 16.20 mg g^?1, respectively. The Cu‐IISG offered a fast kinetics for the adsorption and desorption of Cu(II), which can be used for on‐line preconcentration and detection. Two certified reference materials of GBW07301a sediment and GBW07401 soil were analyzed and the determined values were in a good agreement with the certified values. The developed method was also successfully applied to the determination of trace copper in tea leaf with satisfactory results (recovery between 96.3% and 102.3%).     

A Nitrogen‐Rich 2D sp2‐Carbon‐Linked Conjugated Polymer Framework as a High‐Performance Cathode for Lithium‐Ion Batteries

A two‐dimensional (2D) sp²‐carbon‐linked conjugated polymer framework (2D CCP‐HATN) has a nitrogen‐doped skeleton, a periodical dual‐pore structure and high chemical stability. The polymer backbone consists of hexaazatrinaphthalene (HATN) and cyanovinylene units linked entirely by carbon–carbon double bonds. Profiting from the shape‐persistent framework of 2D CCP‐HATN integrated with the electrochemical redox‐active HATN and the robust sp² carbon‐carbon linkage, 2D CCP‐HATN hybridized with carbon nanotubes shows a high capacity of 116 mA h g^?1, with high utilization of its redox‐active sites and superb cycling stability (91 % after 1000 cycles) and rate capability (82 %, 1.0 A g^?1 vs. 0.1 A g^?1) as an organic cathode material for lithium‐ion batteries.     

Octa[4‐(9‐carbazolyl)phenyl]silsesquioxane‐Based Porous Material for Dyes Adsorption and Sensing of Nitroaromatic Compounds

A new fluorescent hybrid porous polymer (HPP) is synthesized by an anhydrous FeCl₃‐mediated oxidative coupling reaction of octa[4‐(9‐carbazolyl)phenyl]silsesquioxane (OCPS). The polymer possesses a surface area of 1741 m² g^?1 and hierarchical bimodal micropores (1.41 and 1.69 nm) and mesopores (2.65 nm). The material serves as an excellent adsorbent for CO₂ and dyes with high adsorption capacity for CO₂ (8.53 wt %,1.94 mmol g^?1), congo red (1715 mg g^?1) and rhodamine B (1501 mg g^?1). In addition, the presence of peripheral cabozolyl groups with extended π‐conjugation in the crosslinked framework imparts luminescent character to the polymer and offers the detection of nitroaromatic compounds.     

A Bio‐inspired Nano‐pocket Spatial Structure for Targeting Uranyl Capture

Biology has evolved excellent spatial structures for high‐selectivity and high‐affinity capture of heavy metals. Inspired by the spatial structure of the superb‐uranyl binding protein SUP, we mimic the spatial structure of SUP in metal–organic frameworks (MOFs). The MOF UiO‐66‐3C4N fabricated by introducing 4‐aminoisophthalic acid into UiO‐66 shows high uranyl adsorption capacity both in simulated seawater and in natural seawater. In natural seawater, UiO‐66‐3C4N exhibits 17.03 times higher uranium extraction capacity than that of vanadium, indicating the high selectivity of the adsorbent. The EXAFS analysis and DFT calculation reveal that UiO‐66‐3C4N forms smaller nano‐pocket for uranyl capture than that of SUP protein, which can both restrict the entrance of the other interfering ions with larger size and reinforce the binding by increasing the coordination interaction, and therefore qualify the nano‐pocket with high affinity and high selectivity to uranyl.     

A Self‐Standing and Flexible Electrode of Yolk–Shell CoS2 Spheres Encapsulated with Nitrogen‐Doped Graphene for High‐Performance Lithium‐Ion Batteries

Flexible lithium‐ion batteries (LIBs) have recently attracted increasing attention with the fast development of bendable electronic systems. Herein, a facile and template‐free solvothermal method is presented for the fabrication of hybrid yolk–shell CoS₂ and nitrogen‐doped graphene (NG) sheets. The yolk–shell architecture of CoS₂ encapsulated with NG coating is designed for the dual protection of CoS₂ to address the structural and interfacial stability concerns facing the CoS₂ anode. The as‐prepared composite can be assembled into a film, which can be used as a binder‐free and flexible electrode for LIBs that does not require any carbon black conducting additives or current collectors. When evaluating lithium‐storage properties, such a flexible electrode exhibits a high specific capacity of 992 mAh g^?1 in the first reversible discharge capacity at a current rate of 100 mA g^?1 and high reversible capacity of 882 mAh g^?1 after 150 cycles with excellent capacity retention of 89.91 %. Furthermore, a reversible capacity as high as 655 mAh g^?1 is still achieved after 50 cycles even at a high rate of 5 C due to the yolk–shell structure and NG coating, which not only provide short Li‐ion and electron pathways, but also accommodate large volume variation.     

Spidroin-Inspired,High-Strength,Loofah-Shaped Protein Fiber for Capturing Uranium from Seawater

The unique three-dimensional structure of spidrion determines the outstanding mechanical properties of the spider silk fiber. Inspired by the similarity of the three-dimensional structure of superb-uranyl binding protein (SUP) to that of spidroin, a dual-SUP (DSUP) chimeric protein fiber with high tensile strength is designed. The DSUP hydrogel fiber exhibits a loofah-shape structure by the cross-interaction of the protein nanofiber. Full exposure of abundant functional uranyl-binding sites in the stretchable loofah-shape hydrogel protein fiber give the DSUP fiber a groundbreaking uranium extraction capacity of 17.45 mg g⁻¹ with an ultrashort saturation time of 3 days in natural seawater. This work reports the design of an adsorbent with ultrahigh uranium extraction capacity and explores a strategy for fabricating artificial high-strength functional non-spidroin protein fiber.     

Facile Synthesis of High‐Quality Plasma‐Reduced Graphene Oxide with Ultrahigh 4,4′‐Dichlorobiphenyl Adsorption Capacity

High‐quality reduced graphene, termed PG, has been synthesized by a simple, low‐cost, and green plasma approach, and applied as adsorbent to remove 4,4′‐dichloribiphenyl (4,4′‐DCB) from aqueous solutions. As a comparison, the adsorption of 4,4′‐DCB on graphene oxide (GO) and multiwalled carbon nanotubes (MWCNTs) was also studied under the same experimental conditions. PG performs significantly better with regard to 4,4′‐DCB adsorption than GO and MWCNTs, or any reported nanomaterials, with a maximum adsorption capacity (q_max) of 1552 mg g^?1 at pH 7.0. The high affinity of 4,4′‐DCB to PG is mainly a result of strong π–π interactions, as also confirmed by DFT calculations. The results reveal that PG sheets hold promise for the removal of persistent organic pollutants. We expect possible applications of this fast and mild plasma technique in the fabrication of nanomaterials and envisage their use in a variety of advanced chemical processes.     

Three‐Dimensional Macroassembly of Sandwich‐Like,Hierarchical, Porous Carbon/Graphene Nanosheets towards Ultralight,Superhigh Surface Area,Multifunctional Aerogels

A new, ultralight, superhigh surface area, multifunctional aerogel, which is macroassembled from sandwich‐like, hierarchical, porous carbon/graphene nanosheets, is described. The multifunctional aerogel was characterized by means of XRD, SEM, TEM, Raman spectroscopy, and UV/Vis absorption spectroscopy. The multifunctional aerogel had an ultralow density of 8 mg cm^?3 and a superhigh surface area of 2650 m² g^?1. The multifunctional aerogel was thermal stability and compressible. Meanwhile, the multifunctional aerogel exhibited high capacity for the adsorption of oils and organic solvents, unexpectedly high hydrogen adsorption and good electrochemical performance.     

Reduced Graphene Oxide‐Supported TiO2 Fiber Bundles with Mesostructures as Anode Materials for Lithium‐Ion Batteries

Although the synthesis of mesoporous materials is well established, the preparation of TiO₂ fiber bundles with mesostructures, highly crystalline walls, and good thermal stability on the RGO nanosheets remains a challenge. Herein, a low‐cost and environmentally friendly hydrothermal route for the synthesis of RGO nanosheet‐supported anatase TiO₂ fiber bundles with dense mesostructures is used. These mesostructured TiO₂‐RGO materials are used for investigation of Li‐ion insertion properties, which show a reversible capacity of 235 mA h g^?1 at 200 mA g^?1 and 150 mA h g^?1 at 1000 mA g^?1 after 1000 cycles. The higher specific surface area of the new mesostructures and high conductive substrate (RGO nanosheets) result in excellent lithium storage performance, high‐rate performance, and strong cycling stability of the TiO₂‐RGO composites.     

A Bipolar and Self‐Polymerized Phthalocyanine Complex for Fast and Tunable Energy Storage in Dual‐Ion Batteries

Bipolar redox organics have attracted interest as electrode materials for energy storage owing to their flexibility, sustainability and environmental friendliness. However, an understanding of their application in all‐organic batteries, let alone dual‐ion batteries (DIBs), is in its infancy. Herein, we propose a strategy to screen a variety of phthalocyanine‐based bipolar organics. The self‐polymerizable bipolar Cu tetraaminephthalocyanine (CuTAPc) shows multifunctional applications in various energy storage systems, including lithium‐based DIBs using CuTAPc as the cathode material, graphite‐based DIBs using CuTAPc as the anode material and symmetric DIBs using CuTAPc as both the cathode and anode materials. Notably, in lithium‐based DIBs, the use of CuTAPc as the cathode material results in a high discharge capacity of 236 mAh g^?1 at 50 mA g^?1 and a high reversible capacity of 74.3 mAh g^?1 after 4000 cycles at 4 A g^?1. Most importantly, a high energy density of 239 Wh kg^?1 and power density of 11.5 kW kg^?1 can be obtained in all‐organic symmetric DIBs.     

Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen‐Doped Carbon Composites For High‐Performance Lithium–Sulfur Battery Cathodes

Despite the high theoretical capacity of lithium–sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon‐nanotube‐interpenetrated mesoporous nitrogen‐doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g^?1 after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer‐sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm^?2) with a high sulfur loading of approximately 5 mg cm^?2, which is ideal for practical applications of the lithium–sulfur batteries.