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Herein, a design of multifunctional hybrid adsorbent made of a magnetic core and a zeolite imidazolate framework (ZIF-8) shell embedded with carbon dots (CDs) is synthesized to combine detection with separation and recycling of uranium from aqueous solution. The adsorbents retain the strong superparamagnetic behavior of Fe3O4 nanoparticles and similar luminescence of carbon dots. Interestingly, the adsorbents not only exhibit obviously fluorescence response for U (VI) but also enhance U (VI) adsorption performance via assisting with the loaded‑carbon dots. The adsorption processes of U(VI) on Fe3O4-CMC@ZIF-8 and Fe3O4-CMC@ZIF-8@CDs well fit with the pseudo-second-order model. The maximum U(VI) adsorption amount of Fe3O4-CMC@ZIF-8@CDs is high as 606.06 mg/g at pH = 4.0 and T = 298 K with Langmuir model, which is obviously higher than that of Fe3O4-CMC@ZIF-8 (564.97 mg/g). Particularly, BET, FTIR and XPS results show that the improvement of adsorption properties on Fe3O4-CMC@ZIF-8@CDs is mainly ascribed to the large specific surface area and abundant nitrogen/oxygen functional groups on the surface, suggesting that the main interaction mechanisms are diffusion and coordination. The design for hybrid materials provides a convenient way to achieve a multifunctional adsorbent with detection, separation and recycling properties for uranium.

In recent years, metal-organic frameworks (MOFs), especially zeolite-imidazole frameworks (ZIFs), have been attracting widespread attention as templates for the synthesis of sensing materials. Limited researches, however, have been carried out to utilize bimetallic ZIFs in gas sensing, as the existing studies mostly involve monometallic ZIFs. Here in, the core-shell structure of ZnO and Co3O4 composite (CS-ZnO/Co3O4) was synthesized via chemical etched to Co/Zn based zeolitic imidazolate framework (Co/Zn-ZIF) with subsequent annealing. The morphology, composition and surface characteristics of the as-obtained samples were confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET). Moreover, the gas sensing measurements were implemented under various atmospheres. The response of CS-ZnO/Co3O4 sensor to 100 ppm ethanol at 200 °C achieves 38.87, which is 2.8 times that of single-shell ZnO/Co3O4 (SS-ZnO/Co3O4). The improved response is mainly attributed to the core-shell structure, which offers larger surface area, more active sites for gas diffusion and the formation of p-n heterojunction between ZnO and Co3O4.

In order to meet the application requirements of portable and wearable devices, the high-efficiency energy storage units with high energy density, high power density and long cycle life are urgently needed. In this work, we have successfully fabricated novel flexible electrode comprising NiCo2S4@CoMoO4 core–shell nanowire arrays on carbon cloth via a facile three-step hydrothermal process. Benefiting from the unique hierarchical structure and their synergistic effects between CoMoO4 and NiCo2S4, the supercapacitor electrode realizes a fast electron and ion transfer, a large electroactive surface area and superior conductivity. As a result, the NiCo2S4@CoMoO4 electrode exhibits superior performances with an outstanding specific capacitance of 2118.8 F g−1 at 1 A g−1 and an excellent rate capability of 81.6% at 20 A g−1. After 5000 cycles, the NiCo2S4@CoMoO4 electrode shows an excellent cyclic performance with 88.6% capacity retention. The excellent performance of electrode is also confirmed by assembling all-solid-state asymmetric supercapacitor, which delivers a high energy density of 66.6 Wh kg−1 as well as the maximum power density of 16 kW kg−1. This work demonstrates that the NiCo2S4@CoMoO4 electrode provides a promising material for the energy storage applications in the future.

Flower-like Bi5O7I microspheres modified with Ag nanoparticles are prepared, exhibiting excellent surface plasmon resonance. Bi5O7I/Ag/acrylate fluoroboron polymer (AFBP) ternary assembly films are also fabricated using Bi5O7I/Ag composites uniformly distributed in acrylate fluoroboron polymer. The structure and photocatalytic properties of Bi5O7I/Ag are characterized. Characterization results indicate that Bi5O7I/Ag has a large specific surface area, a low band gap, and excellent visible light response. To evaluate the properties of the Bi5O7I/Ag/AFBP ternary assembly film, laboratory diatom assays and antibacterial activity are tested. The results show excellent diatom anti-settlement performance and high antibacterial rates of 99.63% for Escherichia coli and 99.92% for Staphylococcus aureus. Photocatalytic degradation of 2,4,6-trichlorophenol by visible-light irradiation for 150 min shows a removal rate of 95%, which is attributed to charge efficiency separation. Simultaneously, the photodegradation pathway and TOC of 2,4,6-trichlorophenol are analyzed. Thus, this study shows the significance of assembly film for potential marine applications in the future.

3D self-assembly polyethyleneimine-modified graphene oxide hydrogel (PEI-GH) was successfully synthesized via a simple one-step method without using other harsh chemicals. The unique three-dimensional (3D) porous network of PEI-GHs is achieved by using polyethyleneimine (PEI) as the cross-linking agent which also facilitate the self-assembly of GO sheets. With unique porous structure, large surface area and sufficient active sites, the PEI-GH has outstanding adsorption capacity (898 mg/g), large removal rate (>90% at ppm level, or ∼85% for ppb level simulated seawater) and high selectivity of uranium. The adsorption process was described well with the pseudo-second-order kinetic model and Langmuir isotherm model. The thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic. Based on the above results, the PEI-GH materials exhibits promising adsorption performance and high removal rate for uranium (VI) from aqueous solution and simulated seawater.

Polyacrylonitrile fibers (PANF) covalently modified with lysine (PAN-Lys) was facilely synthesized and carefully characterized. The critical factors affecting U(VI) adsorption from aqueous solution were exploited, such as initial pH, contact time, concentration and temperature. The adsorption process is strongly dependent on solution pH. With excellent adsorption capacity and high affinity toward U(VI), the process for U(VI) is extremely rapid and the equilibrium can be reached within 20 min. The thermodynamics and kinetics were strictly evaluated. In addition, the hypothetical adsorption mechanisms were proposed. Moreover, the adsorption behavior at low concentrations (3–30 μg L −1 ) in simulated seawater was also investigated. Therefore, PAN-Lys can be potentially utilized for the efficient removal of U(VI) from seawater.

In our works, the reduced graphene oxide (rGO) ink was prepared successfully. Then, the thin rGO film was fabricated by using inkjet printing method, which can act as a high-conductive supporter for anchoring more active materials. Hence, the Ni-Co LDH as a main active material was applied to enhance the electrochemical activity via one-step electrochemical deposition method. To further meet practice application, the electrochemical performances and mass loading of electroactive material were improved by repeating inkjet printing and electrochemical deposition method. The capacity of Ni-Co LDH/rGO/Ni-Co LDH/rGO is reached to 227 mAh g−1 at 1.2 A g−1, and the capacity value can remain 78.7% after charge-discharge 5000 cycles. The two-electrode supercapacitors were fabricated from the Ni-Co LDH/rGO/ Ni-Co LDH/rGO as positive electrode and commercial active carbon as negative electrode. The improvements of electrochemical properties of Ni-Co LDH/rGO/Ni-Co LDH/rGO//AC can be achieved in energy density of 84.9 Wh kg−1 and power density of 424 kW kg−1.