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The extraction of uranium from nuclear wastewater through photocatalysis represents a highly viable, environmentally friendly, and sustainable approach, contributing significantly to mitigating environmental degradation while facilitating the efficient recovery of uranium resources. Nonetheless, the development of highly efficient photocatalysts with rapid charge carrier migration and surface reaction kinetics for the effective removal of U(Ⅵ) from uranium-containing wastewater remains a formidable challenge. This study successfully employed template-free self-assembly techniques to fabricate hollow tubular g-C3N4(TCN) and synthesized a tubular donor-acceptor(D-A) organic semiconductor photocatalyst, B-TCNx, by incorporating hydroquinone into the framework of TCN. This innovative photocatalyst was utilized for the photocatalytic removal of U(Ⅵ) under ambient air conditions. The construction of an intra-molecular D-A system enables the separate accumulation of electrons and holes in the acceptor and donor moieties, thereby significantly reducing electron-hole recombination. Furthermore, the spatial separation of electrons and holes in the acceptor and donor moieties leads to the formation of an intrinsic electric field, which facilitates the migration of charge carriers. The research findings indicate that B-TCN60 achieved a remarkable removal rate of 96.8% for U(Ⅵ) within 120 minutes, with a kinetic constant(0.03114 min−1) that is 2.58 times higher than that of TCN(0.01215 min−1). Moreover, negligible performance variation was observed after five consecutive cycles, demonstrating the excellent stability and reproducibility of the photocatalyst. The enhanced performance of B-TCN60 can be attributed to its unique structural and electronic properties. The hollow tubular structure of TCN provides a high surface area, which is beneficial for the adsorption of uranium ions. Additionally, the incorporation of hydroquinone into the TCN framework not only improves the light absorption properties of the photocatalyst but also plays a crucial role in the formation of the D-A system. The effective separation of charge carriers within the D-A system minimizes recombination losses and maximizes the efficiency of the photocatalytic process. The study’s findings underscore the potential of D-A organic semiconductor photocatalysts in addressing environmental challenges associated with nuclear waste, while also enhancing the recovery of valuable uranium resources. The novel approach of utilizing a D-A system in the photocatalyst design opens new avenues for the development of advanced materials with superior photocatalytic performance. The innovative use of template-free self-assembly techniques to fabricate hollow tubular g-C3N4 and the successful synthesis of the B-TCNx photocatalyst represent significant advancements in the field. The high removal efficiency, stability, and reproducibility of B-TCN60 highlight its potential for practical applications in environmental remediation. This work not only contributes to the field of environmental remediation but also offers a sustainable solution to the global issue of nuclear waste management.

The development and application of nuclear energy is often considered as a potential solution to meet the increasing energy demand. However, it is important to acknowledge that the utilization of nuclear energy resources and the treatment of nuclear waste pollution pose significant challenges that require careful consideration and management. Therefore, it is crucial to address the challenges of uranium pollution treatment and uranium resource recovery to ensure the sustainable development of nuclear energy. The technology of photocatalytic reduction has been found to have a synergistic adsorption reduction ability, which allows it to overcome the thermodynamic limitations of single adsorption removal. As a result, photocatalytic reduction technology is widely recognized as having great potential in the removal and recycling of uranium in nuclear waste liquid. One of the key factors for the effective application of this technology is the acquisition of a catalyst with high photocatalytic reduction ability. Nitride carbon materials are considered an ideal photocatalyst for photocatalytic reduction of U（Ⅵ） due to their excellent photochemical properties, excellent physicochemical adjustability, and good chemical stability. However, the pure g-C3N4 photocatalyst still suffers from its low separation efficiency of photogenerated charge carriers, which results in unsatisfactory photocatalytic activity. In recent years, research on modifying and applying carbon nitride has provided in-depth insights into the reduction of uranium through photocatalysis. Discussing the strategy of modifying C3N4, constructing heterojunction nanostructures, and utilizing them for the photocatalytic reduction of uranium, along with the mechanisms involved. This review summarizes the recent significant progress on the design of g-C3N4-based heterostructure photocatalysts and their special separation/transfer mechanisms of photogenerated charge carriers. On the one hand, according to the key steps of photocatalytic uranium reduction, modification strategies using g-C3N4 photocatalysts can be classified into the following groups: morphology modification, band-structure regulation, and heterostructure construction. Moreover, according to the different transfer mechanisms of photogenerated charge carriers between g-C3N4 and the coupled components, the g-C3N4-based heterostructure photocatalysts can be divided into the following categories: g-C3N4-based conventional Type-Ⅱ heterojunction, g-C3N4-based Z-scheme heterojunction, g-C3N4-based S-scheme heterojunction, and g-C3N4/metal heterostructure. We also focused on the structure-activity relationship between the modification of photocatalytic materials based on carbon nitride and their photocatalytic reduction performance for U（Ⅵ）, as well as the mechanism of their catalytic reduction removal. Finally, this section offers concluding remarks and prospects for exploring the challenges and opportunities faced by advanced carbon nitride-based photocatalytic materials in the removal of uranium pollution and the recovery of uranium resources. It also provides directions for future breakthroughs.

With the rapid development of nuclear energy, uranium as the main element of nuclear energy production, its source has been widely explored. At present, uranium resources mainly come from uranium mining, and a lot of radioactive uranium containing wastewater is produced in the process of uranium mining. Until now, the treatment technology of uranium mine wastewater is still in the research and development stage in China, which leads to the storage of a large amount of uranium mine wastewater and the discharge of nuclear waste liquid, which poses a threat to human health and the environment due to the comprehensive effect of chemical toxicity and radiation toxicity. On the other hand, other metal cations in uranium wastewater, such as Ca2+ and Mg2+, compete with U(Ⅵ) for active sites, making it difficult for most treatment methods to effectively recover uranium resources from uranium wastewater. Therefore, how to effectively treat radioactive uranium mine wastewater is full of challenges. Photocatalysis is a kind of green environmental protection technology with natural selectivity to non-variable valence ions, which can precipitate the soluble U(Ⅵ) in wastewater. The photocatalysis technology is expected to overcome the competition between metal cations and uranium for active sites, and realize the efficient extraction of U(Ⅵ) in uranium mine wastewater. In this study, ZIF-8-derived Zinc@iron oxide(D-ZnO@FexOy) heterostructures were prepared by impregnation of metal salt solution and high-temperature pyrolysis using ZIF-8 as a precursor for photoassisted reduction of U(Ⅵ) in uranium ore wastewater. The electron transport mode of D-ZnO@FexOy in S-scheme heterojunction is deduced by calculating the work function and band structure. Under photoexcitation, the direction of electron flow changes, the useless electrons and holes recombine at the interface, and the electrons and holes with strong redox ability are retained and participate in the photocatalytic reaction. Compared with D-ZnO and FexOy, this kind of spatially separated photogenerated electrons and holes have stronger redox ability and longer electron lifetime. Meanwhile, the internal electric field formed at the heterojunction interface can effectively enhance the directional electron migration, providing a strong power for promoting the photoassisted reduction of uranium. Therefore, compared with iron oxide(FexOy) and ZIF-8-derived ZnO(D-ZnO), the S-type heterostructure D-ZnO@FexOy exhibits stronger photoassisted uranium reduction ability(>95%) in the presence of multiple competing ions, and the material has good anti-interference and stability. High U(Ⅵ) removal performance(above 86%) is maintained after 5 cycles. The mechanism study shows that hydroxyl radical and superoxide radical are the main active species of photocatalytic reduction of U(Ⅵ). U(Ⅵ) is deposited on the surface of the material in the form of (UO2)O2•2H2O crystals. This study provides a valuable way to explore the photocatalyst with high efficiency photoelectron separation to reduce U(Ⅵ).

Extracting uranium from seawater is an effective strategy for sustainable nuclear fuel supplementation. Uranium in seawater mainly exists in the form of hexavalent uranyl(U(Ⅵ)), although the total amount is large, the mass fraction of U(Ⅵ) is only 3.3×10−9, and many metal ions coexist with uranium. Extracting uranium from seawater is extremely challenging. Electrochemical seawater uranium extraction has become an emerging method for seawater uranium extraction due to its advantages over physical and chemical adsorption processes, such as fast reaction rate, strong anti-interference ability, and simple desorption. However, due to the lack of research on the structure-activity relationship between catalysts and uranium extraction performance, the rational design of highly active electrocatalysts remains a challenge. In this work, we proposed an interface bonding strategy by using a simple hydrothermal method to bond the {2 2 2} fact of octahedral Fe3O4 to the {0 0 2} fact of MoS2. This significantly improves the electron transfer rate at the interface and the cycling stability of Fe3O4, verifying the feasibility of interface bonding for the electrochemical extraction of uranium from seawater. After 7 hours of electrochemical extraction in a simulated solution, the extraction efficiency of uranium can reach 96%. Meanwhile, the experimental results of coexisting ion extraction of uranium indicated that MoS2/Fe3O4 has good selectivity for uranium and anti-interference ability against coexisting ions. Electrochemical extraction is also performed in 10 L natural seawater with a yield of 27.2 μg. The extraction amount of uranium is 5.44 mg/g. A series of characterizations such as XPS and HRTEM, show that Fe3O4 is dispersed on the surface of MoS2 and effectively bound through interfacial interactions. This dispersion effectively solves the aggregation problem of Fe3O4, and the stability of MoS2 structure ensures the cycling stability of Fe3O4. By combining the MoS2 and Fe3O4 at the interface, an efficient electron transfer channel can be constructed, accelerating electron transfer and achieving the goal of simultaneously improving the selectivity, stability, and electron transfer rate of the catalyst. Therefore, the interfacial regulation strategy proposed in this work utilizes the synergistic effects of different components in the composite material to achieve stability and the cyclicity of the catalyst in seawater uranium extraction. At the same time, the interface control strategy will also provide a feasible solution for achieving efficient reduction and extraction of uranyl in a series of complex environments such as seawater. And the electron transfer path and the species change of uranium during catalytic reduction need to be further explored in the mechanism analysis in this work.

In this work, the coordination chemistry of the uranyl ion(\begin{document}${\mathrm{UO}}_2^{2+} $\end{document}) with N, N-dimethyl-diglycolamic acid(HDMDGA, HLI) and N, N-diethyl-diglycolamic acid(HDEDGA, HLII) has been systematically studied through thermodynamic and structural analysis, by means of both potentiometric and spectroscopic titration, as well as Raman spectroscopy and X-ray diffractometry. The protonation constants of L−(L=LI, LII) and the stability constants of the uranyl complexes were determined by potentiometric and spectroscopic titrations in 1.0 mol/L NaClO4, with the molar absorption spectra of all species deconvoluted in the process of the latter titration. Besides, the standard Raman spectra of various complexes were confirmed by Raman spectroscopic titration. Furthermore, the single crystal of compound \begin{document}${\mathrm{UO}}_2{\mathrm{L}}^{{\mathrm{II}}}_2 $\end{document} was obtained by slow evaporation of aqueous solution containing uranyl ion and LII ligands at room temperature. X-ray diffraction analysis shows a monoclinic crystal system in P21/c space group, with lattice parameters: a=15.5096(6) Å（1 Å=0.1 nm）, b=7.7934(3) Å, c=11.3732(4) Å, α=90°, β=97.388(4)°, γ=90° and Z=2. Although both ligands show a similar structure and protonation constant, the different values of stability constant in aqueous solution and the different bond length of U-O in two complexes indicate the distinct coordination ability for two ligands with \begin{document}${\mathrm{UO}}_2^{2+} $\end{document}, where HDEDGA performs better. Like the crystal structure of \begin{document}$ {\mathrm{UO}}_2{\mathrm{L}}^{{\mathrm{I}}}_2$\end{document}, the ligand LII in the \begin{document}${\mathrm{UO}}_2{\mathrm{L}}^{{\mathrm{II}}}_2 $\end{document} complex coordinates with \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} in a tridentate manner, with three oxygen atoms(amide oxygen, ether oxygen and carboxylic acid oxygen) coordinating with the linear \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} at the equatorial plane. In addition, the diffuse reflectance spectra of the \begin{document}${\mathrm{UO}}_2{\mathrm{L}}^{{\mathrm{II}}}_2 $\end{document} crystal show characteristics significantly different from the absorption spectra of the corresponding complex in the aqueous solution. Meanwhile, the Raman shift of the characteristic peak of uranyl ion between hydrated uranyl ion and the 1∶1 complex(U∶ LII) is significantly larger than that between 1∶1 and 1∶2. Therefore, it is speculated that the structure of the 1∶2 complex in aqueous solution is supposed to be different from that in the solid crystal.

Photocatalytic technology can use photogenerated electrons to reduce easily soluble U(Ⅵ) to insoluble U(Ⅳ). In this work, hierarchical macro/mesoporous g-C3N4-TiO2 composites were synthesized without the introduction of organic templates or auxiliary additives, and were used for photocatalytic reduction of U(Ⅵ). The morphology, structure and optical properties of g-C3N4-TiO2 composites were studied by X-ray diffractometer(XRD), scanning electron microscope(SEM), automatic specific surface area physical adsorption instrument(BET), ultraviolet-visible diffuse reflectance spectrometer(UV-vis DRS) and other advanced characterization equipment. The photocatalytic reduction of U(Ⅵ) of g-C3N4-TiO2 composites was studied by photocatalytic experiments. The results show that g-C3N4-TiO2 composites have the advantages of hierarchical macro/mesoporous TiO2 and g-C3N4, not only have a large specific surface area(174.68 m2/g) and pore channels, but also have a wider light absorption range. Therefore, the removal rate of g-C3N4-TiO2 composites on U(Ⅵ) is as high as 98.4% within 15 min. This work provides new ideas for the treatment of uranium-containing radioactive wastewater.

Photocatalytic assisted uranium extraction technology is a rapidly developed technology for uranium extraction from wastewater and seawater in recent years, which can significantly improve the extraction capacity and extraction rate of uranium. However, the activity of most photocatalysts in air atmosphere is inhibited, which hinders the practical application of this technology. Based on this, this paper discusses the latest progress of photocatalytic assisted uranium extraction technology in air atmosphere, focusing on the analysis of different mechanisms and product characteristics of photocatalytic assisted uranium extraction in air atmosphere, especially the photoreaction and chemical reaction mechanism in the absence of catalyst. There are mainly two mechanisms for the photocatalysis assist uranium extraction. The first one is based on the photocatalytic reduction of U(Ⅵ) to U(Ⅳ). Under illumination, electrons and holes pairs are generated on photocatalysts, and the electrons could reduce the soluble \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} to insoluble uranium oxide(UO2). However, under air atmosphere, at the presence of oxygen, the newly formed UO2 could be oxidated back to \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} and dissolved into solution, resulting in the decrease of uranium extraction performance. Therefore, this mechanism is usually applied under inert atmosphere. Although with proper design of photocatalyst, the oxygen could be covert to \begin{document}${ · {\mathrm{O}}_2^- } $\end{document} to further reduce \begin{document}${\mathrm{UO}}_2^{2+} $\end{document}, the performance is still not comparable with that under inert atmosphere. The other recently developed photocatalysis assisted extraction mechanism is based on the convert of soluble \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} to uranium peroxide((UO2)O2•xH2O), which can work well under air atmosphere. Under light illumination, hydrogen peroxide(H2O2) can be first produced with the assist of efficient photocatalysts or the photoactivity of \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} itself. Then H2O can react with to \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} form insoluble uranium peroxide. As uranium peroxide is stable under air and oxygen may contribute to the formation of H2O2, this mechanism can obtain excellent performance under air. Researchers have developed composite materials such as carbon nitride, carbon dots, graphene aerogels, and metal-organic frameworks(MOFs), which exhibit superior uranium removal performance under aerobic conditions. Besides, research on uranium extraction via photocatalysis under air is still in its infancy, and the specific reaction mechanisms may vary under different environments, necessitating further investigation. Based on the mechanism of uranium extraction via the photo-assisted transformation to uranium peroxides, the design of catalysts and uranium extraction materials will be greatly broadened. Combined with the discussion of the reaction mechanism of uranium extraction under light conditions and the design of catalyst materials, we hope to provide inspiration for researchers to develop highly efficient uranium extraction catalyst and mechanism research under air atmosphere.

In this work, molten salt method was used to prepare highly dispersed graphitic carbon nitride(WSGCN), and chemical reduction method was used to load Cu nanoparticles on WSGCN to prepare Cu-WSGCN composites. FTIR, XRD, XPS, TEM, SEM, ICP-AES, UV-vis DRS, PL spectroscopy, ESR and EIS characterization methods were carried out to investigate the structure and photoelectric properties of the photocatalyst. The results show that compared with WSGCN, Cu-WSGCN has a larger light absorption range and a narrower band gap. In addition, the presence of Schottky barriers at the interface between Cu nanoparticles and WSGCN promotes charge transfer and separation of photogenerated carriers, which improves the photocatalytic ability. The uranium removal rate of Cu-WSGCN composite is relatively high(81.07 %) when the load of Cu nanoparticles is 1%. After three cycles of photocatalytic uranium reduction experiments, the uranium removal rate by 1%Cu-WSGCN can still reach 75.96%, which provides a useful reference for the development of novel materials with high efficiency photocatalytic removal of uranium.

Uranium is the main fuel of nuclear power, and the removal of uranium from uranium-containing wastewater is important for environmental protection and resource recovery. Photo-induced uranyl ion removing is an economical and efficient method to remove U(Ⅵ) from uranium-containing wastewater. Many materials have been used for photo-induced reduction of U(Ⅵ). However, the practical application of most materials is still limited by many factors, such as the complexity of its synthesis process, the harsh conditions required, and the poor selectivity and reusability in the photocatalytic process. More importantly, most materials can only be photocatalyzed under the protection of an inert atmosphere. In the presence of oxygen, the photocatalytic product uranium dioxide(UO2) is unstable and easily oxidized resulting in reduced removal effect, so it becomes particularly vital to find an effective catalyst. Carbon dots(CDs) are a new type of carbon-based materials with excellent fluorescence performance, good water solubility and biocompatibility. However, due to the small size and hydrophilicity of the CDs, it is difficult to separate from water. It needs to be combined with other solid materials when applied. The application of CDs to the photocatalytic removal of uranyl ions in water has rarely been studied. Silica(SiO2) is an ideal loader due to its excellent mechanical strength and irradiation stability, as well as its large specific surface area and easy modification. In this paper, a blue carbon dot was prepared by solvothermal method and CDs/SiO2 composites were synthesized by sol-gel method. The morphology of the composite was characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM) technologies, and their application in photocatalytic removal of uranium were studied. Under visible light irradiation, CDs/SiO2-b can remove more than 95% of uranium in 100 min. Experiments have found that the photo-precipitation rate of silica to uranium after the introduction of carbon dots is about 5.8 times of that of the pure silica, and uranium can be transformed into solid product of (UO2)O2•2H2O under air atmosphere, with a removal capacity of more than 800 mg/g. The morphology and structure of the photocatalytic products were characterized by SEM and XPS technology, and the solid products were easy to separate and remove. In order to evaluate the practical application of CDs/SiO2 light-induced reduction of uranium under visible light irradiation, pH and other influencing factors were systematically studied. Moreover, the removal efficiency of uranium is higher 85% after 5 cycles of recycling, showing excellent recycling performance. CDs/SiO2 composites are simple to prepare and can efficiently remove uranyl ions in water through photoinduction, which provides a new method and material for photoinduced removal of uranium.

The photocatalytic conversion of soluble U(Ⅵ) to insoluble U(Ⅳ) is regarded as an effective method for the separation of solution uranium. During the photocatalytic reactions, the design of photocatalyst plays a role. As a metal free polymer semiconductor, carbon nitride(CN) has attracted increasing attentions in photo-catalytic reduction of U(Ⅵ) under visible light irradiation due to its low cost, easy preparation, excellent physicochemical stability and adjustable structure. However, the application of carbon nitride in photocatalytic U(Ⅵ) reduction is limited by its low photocatalytic reduction efficiency, which is caused by the poor reactive sites low separation rate of charge carriers, and slow transport efficiency of electrons. This study aimed to evaluate the transformation of U(Ⅵ) in aqueous solution over Y-doped CN(YCN). YCN photocatalysts with different amount of Y3+ were prepared by in situ doping to modify the energy band structure and physicochemical properties of carbon nitride. It was revealed that the presence of Y3+ changed the in-plane periodic topology and inter-layer stacking structure of the tri-s-triazine unit of carbon nitride, resulting in the incomplete polymerization of the tri-s-triazine unit. The doping of Y3+ lead to the formation of porous structure in YCN, which increases the specific surface area and the active sites. Comparing with pristine CN, YCN showes enhanced absorbance for light and increases separation rate of charge carriers. The average fluorescence life is subsequently increased under light irradiation, which is 1.8 times for YCN2 than the pristine CN. The EPR spectra demonstrates that, compared to CN, significantly more \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals and less \begin{document}$· {\mathrm{OH}} $\end{document} radicals are generated on YCN2 under light irradiation. The free radical trapping experiments verifies that \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals act as the dominant reactive species for the reduction of U(Ⅵ) and the small amount of other radicals do not bring obvious influence. The enhanced generation of \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals on YCN2 therefore provides favorable conditions for the photocatalytic reduction of U(Ⅵ). When using methanol as a sacrificial agent, it can remove about 95% of U(Ⅵ) within 20 min for the YCN2-containing system under light. The rate of the photocatalytic reduction of U(Ⅵ) on YCN2(0.112 min−1) is 5.3 times higher than CN(0.021 min−1). Analysis of the products reveals that water-soluble U(Ⅵ) is reduced in the photocatalytic reaction, with approximately 80% U(Ⅳ) and 20% U(Ⅵ). The soluble U(Ⅵ) is mainly reduced to insoluble UO2+x deposited on the surface of YCN by \begin{document}$ { · {\mathrm{O}}_2^- } $\end{document} radicals. This study improves the photocatalytic performance of CN for the reduction of U(Ⅵ) by Y3+ doping.

Uranium, as the most important fuel for nuclear power operation, is crucial to ensure the sustainable development of nuclear power. However, the supply-demand contradiction of uranium resources in China has become increasingly prominent, and the gap needs to be filled by overseas development and international market procurement. The photoreduction and electroreduction of uranium under complex conditions are mainly targeted at uranium containing radioactive wastewater, real seawater, and other systems. Uranium containing radioactive wastewater comes from the processes of uranium mining, uranium enrichment, uranium conversion, and manufacture of nuclear fuel elements, with the characteristics of complex interfering ions. Although the total amount of uranium in seawater is very large, the concentration of uranium in seawater is low, making the extraction of uranium from seawater extremely challenging. On the one hand, the reserves of uranium in seawater are nearly a thousand times higher than those on land; on the other hand, the entire application process of the nuclear industry produces a large amount of uranium containing radioactive wastewater. If efficient separation of uranium from seawater and uranium containing radioactive wastewater can be achieved, it can promote the secondary supply of uranium resources and alleviate the supply-demand contradiction of uranium resources in China. Therefore, the development of uranium recovery and extraction technology from seawater and uranium containing radioactive wastewater is important for the sustainable development of the nuclear industry. This paper reviews the recent research progress in separating uranium in complex environments such as seawater and uranium containing radioactive wastewater. In terms of uranium speciation analysis, it describes the coordination environment of complex environmental uranyl and summarizes the advantages of photocatalysis and electrocatalysis in the fields of uranium extraction from uranium containing radioactive wastewater and seawater. In terms of designing photocatalysts, strategies such as element doping, metal loading, defect engineering, and introducing heterojunctions have been summarized for the preparation of photocatalytic semiconductor materials. The modification of functional groups on heterojunctions to regulate their energy band structure had introduced, which improved the overall performance of the material. The integration of selective adsorption and catalytic reduction, electrochemical methods can reduce soluble uranyl ions to neutral and insoluble products for separation, with advantages such as fast kinetics, wide extraction concentration range, and large separation capacity. However, there are also many key technical challenges in the practical application process, such as the competition between multiple cations and uranyl ions in complex systems, and the problem of excessive energy consumption caused by the competing reaction of water splitting during the cathodic uranium extraction process. In terms of electrocatalysis, various aspects such as electrode carrier selection, electrochemical device design, defect engineering, surface engineering, interface engineering, and microbial electrochemistry have been summarized to design electrocatalytic materials. In terms of key technical bottlenecks, combining photocatalysis and electrocatalysis technology with challenges in complex scenarios such as uranium speciation analysis, material functionalization design, intermediate reaction species analysis, uranium extraction mechanism analysis, cost control, and real-world application outcomes, relevant research have focused on challenges such as efficient photocatalytic reduction of uranium under natural light, identification of intermediate uranium species, uranium extraction from uranium containing radioactive wastewater, and seawater extraction from real ocean environments.

In this work, a novel graphite-based electrochemical filter was developed for the efficient and environmentally friendly treatment of uranium tailings leachate. The filter utilizes graphite particles as filler and carbon felt as a conductor, powered by a DC power supply and driven by a peristaltic pump. In a non-circulating continuous operation filter experiment, uranium tailings leachate was tested for uranium removal efficiency under different operating parameters such as voltage and residence time, using both synthetic wastewater and actual uranium mine wastewater. This study is based on the fundamental principles of metal electrochemical reduction. The efficacy of this device for the continuous flow treatment of uranium tailings leachate was systematically investigated. The mechanism of uranium tailings leachate treatment by the electrochemical filter was elucidated through electrochemical analysis and product characterization. The results highlight that voltage and hydraulic retention time are critical factors influencing the efficiency of electrochemical filter treatment. Specifically, 4.0 V and 10 hours were identified as the optimized voltage and suitable hydraulic residence time, respectively, for the treatment of uranium tailings leachate using the electrochemical filter, resulting in a uranium removal rate exceeding 97%. In actual uranium tailings leachate applications, the maximum extraction rate can reach 5275 μmol/(m3∙h), confirming the feasibility of electrochemical filter in removing uranium from actual uranium tailings leachate and its good selectivity in complex water quality applications, the device can be quickly applied to uranium tailings leachate collection facilities and achieve in-situ uranium extraction. The voltage increase can significantly enhance the uranium extraction performance and can be portablely deployed in uranium mine water. In-situ uranium processing and recovery is achieved in processing and collection facilities. Characterization techniques such as field emission scanning electron microscope-energy spectrum analyzer(FESEM-EDS) and X-ray photoelectron spectrometer(XPS) were employed to analyze the reaction products on the graphite particles, revealing that uranium was evenly distributed on the surface of graphite particles and exhibits a stable crystal structure, the main mechanism responsible for uranium removal was adsorption-reduction, with uranium recovery products deposited on the electrode surface in the form of a mixture of U(Ⅳ) and U(Ⅵ). A cost estimation shows that the operational cost of extracting uranium from uranium tailings leachate using this device falls within the range of 176.6 ￥/kgU to 587.5 ￥/kgU. This cost is significantly lower than that of conventional land-based uranium resource development, making it economically viable. This research provides both theoretical and technical support for the efficient and environmentally friendly treatment of uranium tailings leachate.

Abstract The human insulin gene modified with a C-peptide was synthesized according to the plant-preferred codon, and a fusion gene expression vector of insulin combined with green fluorescent protein (GFP) was constructed. The optimization of the flax callus culturing was undertaken, and a more efficient Agrobacterium-mediated genetic transformation of the flax hypocotyls was achieved. The critical concentration values of hygromycin on the flax hypocotyl development, as well as on its differentiated callus, were explored by the method of antibiotic gradient addition, and the application of antibiotic screening for the verification of positive calluses was assessed. The fusion gene of insulin and GFP was successfully inserted into the flax genome and expressed, as confirmed through polymerase chain reaction and Western blotting. In conclusion, we have established a flax callus culture system suitable for insulin expression. By optimizing the conditions of the flax callus induction, transformation, screening, and verification of a transgenic callus, we have provided an effective way to obtain insulin. Moreover, the herein-employed flax callus culture system could provide a feasible, cheap, and environmentally friendly platform for producing bioactive proteins. Graphical Abstract

A copper-catalyzed three-component reaction of diazo compounds, nitriles, and azodicarboxylates to construct 2,3-dihydro-1,2,4-triazoles is reported. Key to the success is the utilization of azodicarboxylates to trap the in-situ formed nitrile ylides from diazo compounds by [3 ​+ ​2]-cycloaddition. Both the acceptor-only and donor-acceptor diazo compounds are all tolerated to the strategy. The synthetic value of this protocol is illustrated by gram-scale synthesis and valuable transformation of the obtained 2,3-dihydro-1,2,4-triazoles.

A dehydroxylative ring-opening Giese reaction of cyclobutanone oximes enabled by photoredox/Ti dual catalysis has been reported in this work. This protocol avoids the prefunctionalization of oximes and the use of stoichiometric triarylphosphine reagents. It also features mild conditions, broad substrate scope and good functional group tolerance. The gram-scale reaction, product derivatization, late-stage functionalization of complex pharmaceutical and natural product derivatives, and oligopeptide modification exhibit the potential application of this methodology in synthetic chemistry.

Two types of poly-porphyrin-based heterogeneous photocatalysts including insoluble polymer and water-soluble nanoparticles exhibited excellent photocatalytic activity in visible-light-induced dehydrogenation in water. The extremely low catalyst loading (0.01 ​mol%) of water-soluble nanoparticles provided so far the highest turnover frequency (TOF) value (333 h-1) for such transformation among reported records.

Catalytic fixed-bed is an efficient and facile system for scalable organic synthesis due to its continuous and fast flow operation process. As a key unit in the fixed-bed system, catalytically active packing materials are required to possess some properties, such as high activity, excellent stability, and porous packing structure. Herein, we prepare a fibrous fixed-bed catalyst by anchoring Pd nanoparticles on N-doped graphene fiber (NHG) (Pd/NGF). Due to the porous and loose packing structure, the resultant Pd/NGF catalyst can be easily filled into the continuous-flow reactor to construct a fixed-bed system with low flow resistance. The corresponding catalytic fixed-bed system exhibits a favourable flow rate (8 ​mL/min) and excellent durability toward reduction reactions of N-containing unsaturated compounds to produce aromatic amines. This work provides a new design concept of fibrous fixed-bed catalysts with dual-active components (i.e., graphene-derived active materials and metal nanoparticles) and catalytic organic synthesis in a continuous-flow process.

A highly efficient, transition-metal- and light-free approach to polyheterocycles via regioselective cascade radical cyclization is developed. The redox-neutral protocol has a broad substrate scope with good functional group tolerance and probably undergoes a SET process, which is initiated by catalytic amounts of quinone in combination with 2.0 equiv. of Cs2CO3.

Asymmetric ring-expansion reactions of silacyclobutanes (SCBs) with alkynes have evolved as one of the powerful protocols for the construction of silicon-stereogenic compounds. However, the achievement of highly enantioselective annulation of SCBs with terminal alkynes remains a challenge. Herein, we report a rhodium-catalyzed asymmetric annulation reaction of SCBs with terminal alkynes, which relies on the newly identified chiral sulfinamide phosphine ligand Ming-Phos. This catalytic system exhibits unique effects under mild conditions, leading to the direct synthesis of structurally diverse chiral silacycles in moderate to good yields with high enantioselectivities (up to 95% ee).

We herein reported a sustainable synthesis of 3,3-disubstituted oxindoles via a Michael-type reaction based on the CuBr-catalysed capture of carboxylic oxonium ylides with isatylidene malononitrile. The reaction is characterized by a high atom economy and low economic constraints. The catalyst CuBr could be conveniently recyclized. The products of the reaction were found to be inhibitory against Na ion channels. We expect the reaction to shed the light on synthesis of biologically interesting molecules directed by principles of green chemistry.

The nitrile compounds are present in a variety of biologically active natural products and pharmaceuticals, and the nitrile groups are versatile synthetic intermediates to other functionalized compounds. Herein, the asymmetric reduction of α, β-unsaturated nitriles with water as a hydrogen source is reported. The reaction is catalyzed by the complex of [Ir(COD)Cl]2 and (Ra, S)-Ph-Bn-SiPhox, and allows the preparation of useful enantioenriched chiral 3,3-disubstituted propionitriles with high optical purities in mild conditions.

A metal-free, efficient and easy-to-hand protocol for the synthesis of 2-perfluoroalkylquinazolins has been achieved by Eosin B catalyzed radical cascade arylation/cyclization reaction of fluorinated imidoyl isothiocyanates with aryldiazonium Salts. A variety of highly functionalized quinozaline derivatives bearing pharmaceutically important thiol and fluoroalkyl groups were efficiently assembled with broad substrate scope and good functional group tolerance. A series of mechanism experiments indicate that this reaction undergoes a radical cascade arylation/cyclization pathway.

A palladium/chiral N,N′-disulfonyl bisimidazoline (Bim)-catalyzed asymmetric addition of arylboronic acids to isoquinoline-1,3,4-trione-derived ketimines is reported, leading to the generation of a series of functionalized isoquinoline-1,3(2H,4H)-diones bearing one quaternary carbon-amino functionality in good to excellent yields with ≥95% ee in most cases. The reaction has remarkable compatibility with both substrate scopes, providing a highly enantioselective entry to chiral heterocyclic α-tertiary amines.

The realm of application of organometallic catalysis to organic synthesis has witnessed a transformative shift in recent years, owing much to the evolution of ate complexes from mere reagents to versatile catalysts. Ate complexes, formed through the coordination of a neutral Lewis acid with an organic anionic base, have emerged as pivotal intermediates that not only facilitate organic transformations but also serve as efficient catalysts in a wide range of chemical reactions. This review presents the fascinating journey of ate complexes, highlighting their development from stoichiometric reagents to active catalysts. Historically, ate complexes were primarily regarded as stoichiometric species essential for various metal-catalyzed transformations. However, constant research has unveiled their potential as catalysts in their own right, reshaping the landscape of modern organic synthesis. In this minireview, we discuss the pivotal role of ate complexes in the evolution of organic synthesis, from their early days as reactive intermediates to their current stature as catalytic pioneers offering a glimpse into the exciting future of this dynamic field.

The peroxygenases are ideal biocatalysts for the selective oxyfunctionalisation of stable C–H bonds. However, the catalytic efficiency of this approach is limited due to enzyme lability toward oxidant H2O2. Although the reported in-situ H2O2 generation system enables the stable biocatalytic process without deactivating the enzyme, the greatest catalytic potential of peroxygenases still cannot be fulfilled effectively. To address the above issue, a H2O2 generation-detection-regulation platform that integrated an effective organocatalyst-driven H2O2 generation system, a precise electrochemical H2O2 real-time detection device, and a convenient H2O2 regulation strategy was first developed. The suitable range of H2O2 generation rate for maximizing the catalytic efficiency of peroxygenases while minimizing inactivation of the enzyme was firstly obtained by simply adjusting the amount of organocatalyst. According to the determined suitable range, the C–H oxyfunctionalisation efficiency of peroxygenases for each substrate was significantly boosted, achieving ∼3-fold of the reported highest turnover frequency.

Micro-nanobubbles (MNBs) are tiny bubbles of water used in various industries. The production methods and properties of concrete containing MNBs and the applications of MNBs in different industries are reviewed. Then, the effect of MNBs on the properties of fresh and hardened concrete is described. Next, we assessed the advantages and disadvantages of using MNBs in different types of concretes, environmental and economic impact, and research gaps in the concrete containing MNBs. Even though the presence of MNBs in concrete has an undesirable effect on workability and rheology parameters, the results of workability are in the range of the European Guideline for Self-compacting Concrete regulations and the British Standard for conventional concrete. In contrast, using sulfo-aluminate cement instead of Portland cement and MNBs in concrete improves rheological characteristics. The review also shows that MNBs improve the mechanical properties of concrete by up to 31% for compressive strength, 10–20% for tensile, and 3–34% for flexural strength. Furthermore, concrete containing MNBs has performed better than conventional concrete in terms of durability properties such as electrical resistivity, ultrasonic pulse velocity, chloride penetration resistance, and resistance to freezing–thawing cycles (F-T cycle). MNBs in concrete reduce the porosity by 17% and decrease the size of the holes. Water absorption of MNB concrete at 28 days decreased by 20%, and chloride permeability reduced by 20%. MNBs in concrete help to develop the resistance of cement-based materials improve the elastic modulus at early ages and increase the ability to resist cracking, which can reduce the crack width. Still, it is necessary to carry out more experimental work for workability and durability, especially for SCC. Even though a few studies indicate a slight impact on the environment, environmental and economic effects, and production challenges need more investigations.

High voltage (HV) outdoor insulators are subjected to both electrical and environmental stresses, which may lead to their failure. Among the causes, corona discharge, humidity and UV radiation are considered to be the most damaging factors. Efforts are therefore underway to investigate new materials for improving the performance of insulating systems. In this research work, silicone-based room temperature vulcanized samples filled with alumina trihydrate (ATH), silicon dioxide and magnesium hydroxide (MH) were prepared and exposed to AC corona discharge for a duration of 110 h. The electric discharge was also accompanied by UV radiation and two different humidity levels. Following aging of the test samples, diagnosis was conducted to assess their integrity. Measurements based on determining the static contact angle demonstrated the loss of hydrophobicity of all the materials, while hydrophobicity recovery phenomena revealed that ATH-doped materials demonstrated a comparatively higher increase in the contact angle than in samples filled with silicone dioxide (silica) and MH. Scanning electron microscopy analysis revealed deep cracks and block-like structures on their surfaces. Similarly, energy-dispersive X-ray analysis indicated the signs of surface oxidation of the aged samples. However, the data of elemental composition exhibited the loss of filler contents as well as that of carbon from the base matrix. The overall assessment showed that resistance to suppress aging is influenced by both the filler type and its concentration in the investigated composites. The ATH-filled composites exhibited outstanding performance when exposed to the rigors of corona discharge and other environmental stresses. This research contributes to materials science and HV engineering by addressing the development of composites for enhanced insulator performance, with future aspects lying in the utilization of nano-composites for advanced functionality and durability.

In this study, atomistic simulations were used to analyze the effects of nonglide stress and temperature on the mobility and structure of pyramidal-I (Pyr-I) and pyramidal-II (Pyr-II) 〈c + a〉 screw dislocations in single-crystal Mg. At a very low temperature (10 K), the pyramidal screw dislocations stably exist on Pyr-II planes and tend to glide on Pyr-I planes. The critical resolved shear stresses (CRSSes) of the pyramidal screw dislocations depend on the migration direction. Once a Pyr-II dislocation is transformed into a stuck core, a very high shear stress (243 and 391 MPa) is required to escape from the immobilized structure. Furthermore, their CRSSes increase with increasing compressive strain and decrease with increasing tensile strain normal to the slip planes. At the intermediate temperature range of 200 K ≤ T ≤ 400 K, the CRSSes of Pyr-I screw dislocations are weakly affected, whereas those of Pyr-II screw dislocations drastically decrease. Thus, both Pyr-I and Pyr-II screw dislocations have similar CRSS values at 400 K. At a higher temperature (500 K), Pyr-I screw dislocations frequently emit basal-〈a〉\langle a\rangle dislocation loops, and the remained dislocations are momentarily immobilized. The basal-〈a〉\langle a\rangle dislocation loops emitted from the 〈c + a〉 dislocations are quickly retracted, and the core structure is recovered as the shear deformation continues. This phenomenon can reduce the mobility of Pyr-I 〈c + a〉 screw dislocations at a higher temperature. The emission of basal-〈a〉\langle a\rangle dislocation loops is enhanced under compression.

The Ni1−x CuxFe2O4 (where x = 0, 0.05, 0.10, 0.15) nano ferrite powder was synthesized through chemical co-precipitation method, NaOH and acid oleic as raw materials. The XRD patterns confirmed the spinal structure phase purity of materials. XRD results showed that lattice parameter decreases with the increase of copper concentration by increasing copper concentration in the parent material. Scanning electron microscopy (SEM) was used to determine the morphology and particle size. SEM analysis indicated that all the samples are in nano size and homogeneous. AC electrical properties of nanoparticles were investigated by employing impedance spectroscopy. The real and the imaginary parts of impedance, permittivity, modulus along with the real part of ac conductivity, and tan delta were measured and analyzed for all synthesized samples in 1 Hz to 7 MHz for different voltages at 300 K.

Abstract Bispecific antibodies (bsAbs) hold promises for enhanced therapeutic potential surpassing that of their parental monoclonal antibodies. However, bsAbs pose great challenges in their manufacturing, and one of the common reasons is their susceptibility to aggregation. Building on previous studies demonstrating the functionality and potential manufacturability of Fab-scFv format bsAb, this investigation delved into the impact of environmental factors—such as pH, buffer types, ionic strength, protein concentrations, and temperatures—on its stability and the reversal of its self-associated aggregates. Mildly acidic, low-salt conditions were found optimal, ensuring bsAb stability for 30 days even at elevated temperature of 40 °C. Furthermore, these conditions facilitated the reversal of its self-associated aggregates to monomers during the initial 7-day incubation period. Our findings underscore the robustness and resilience of Fab-scFv format bsAb, further confirming its potential manufacturability despite its current absence as commercial products. Graphical Abstract

Abstract Since the discovery of graphene and its remarkable properties, researchers have actively explored advanced graphene-patterning technologies. While the etching process is pivotal in shaping graphene channels, existing etching techniques have limitations such as low speed, high cost, residue contamination, and rough edges. Therefore, the development of facile and efficient etching methods is necessary. This study entailed the development of a novel technique for patterning graphene through dry etching, utilizing selective photochemical reactions precisely targeted at single-layer graphene (SLG) surfaces. This process is facilitated by an excimer ultraviolet lamp emitting light at a wavelength of 172 nm. The effectiveness of this technique in selectively removing SLG over large areas, leaving the few-layer graphene intact and clean, was confirmed by various spectroscopic analyses. Furthermore, we explored the application of this technique to device fabrication, revealing its potential to enhance the electrical properties of SLG-based devices. One-dimensional (1D) edge contacts fabricated using this method not only exhibited enhanced electrical transport characteristics compared to two-dimensional contact devices but also demonstrated enhanced efficiency in fabricating conventional 1D-contacted devices. This study addresses the demand for advanced technologies suitable for next-generation graphene devices, providing a promising and versatile graphene-patterning approach with broad applicability and high efficiency.

Abstract Panax notoginseng saponins (PNS) are the main active components of Panax notoginseng. But after oral administration, they need to be converted into rare ginsenosides by human gut microbiota and gastric juice before they can be readily absorbed into the bloodstream and exert their effects. The sources of rare ginsenosides are extremely limited in P. notoginseng and other medical plants, which hinders their application in functional foods and drugs. Therefore, the production of rare ginsenosides by the transformation of PNS using Aspergillus fumigatus was studied in this research. During 50 days at 25 ℃ and 150 rpm, A. fumigatus transformed PNS to 14 products (1–14). They were isolated by varied chromatographic methods, such as silica gel column chromatography, Rp-C18 reversed phase column chromatography, semi-preparative HPLC, Sephadex LH-20 gel column chromatography, and elucidated on the basis of their 1H-NMR, 13C-NMR and ESIMS spectroscopic data. Then, the transformed products (1–14) were isolated and identified as Rk3, Rh4, 20 (R)-Rh1, 20 (S)-Protopanaxatriol, C-K, 20 (R)-Rg3, 20 (S)-Rg3, 20 (S)-Rg2, 20 (R)-R2, Rk1, Rg5, 20 (S)-R2, 20 (R)-Rg2, and 20 (S)-I, respectively. In addition, all transformed products (1–14) were tested for their antimicrobial activity. Among them, compounds 5 (C-K) and 7 [20 (S)-Rg3] showed moderate antimicrobial activities against Staphylococcus aureus and Candida albicans with MIC values of 6.25, 1.25 μg/mL and 1.25, 25 μg/mL, respectively. This study lays the foundation for production of rare ginsenosides. Graphical abstract

Abstract The immunosuppressive tumor microenvironment (TME) has become a major challenge in cancer immunotherapy, with abundant tumor-associated macrophages (TAMs) playing a key role in promoting tumor immune escape by displaying an immunosuppressive (M2) phenotype. Recently, it was reported that M1 macrophage-derived nanovesicles (M1NVs) can reprogram TAMs to an anti-tumor M1 phenotype, thereby significantly alleviating the immunosuppressive TME and enhancing the anti-tumor efficacy of immunotherapy. Herein, we developed M1NVs loaded with mesoporous dopamine (MPDA) and indocyanine green (ICG), which facilitated the recruitment of M2 TAMs through synergistic photothermal and photodynamic therapy. Thereafter, M1NVs can induce M1 repolarization of TAMs, resulting in increased infiltration of cytotoxic T lymphocytes within the tumor to promote tumor regression. This study investigated the effect of phototherapy on the immune environment of liver cancer using single-cell RNA sequencing (scRNA-seq) by comparing HCC tissues before and after MPDA/ICG@M1NVs + NIR treatment. The results showed significant shifts in cell composition and gene expression, with decreases in epithelial cells, B cells, and macrophages and increases in neutrophils and myeloid cells. Additionally, gene analysis indicated a reduction in pro-inflammatory signals and immunosuppressive functions, along with enhanced B-cell function and anti-tumor immunity, downregulation of the Gtsf1 gene in the epithelial cells of the MPDA/ICG @M1NVs + NIR group, and decreased expression of the lars2 gene in immune subpopulations. Eno3 expression is reduced in M1 macrophages, whereas Clec4a3 expression is downregulated in M2 macrophages. Notably, the B cell population decreased, whereas Pou2f2 expression increased. These genes regulate cell growth, death, metabolism, and tumor environment, indicating their key role in HCC progression. This study highlights the potential for understanding cellular and molecular dynamics to improve immunotherapy. Graphical Abstract

Abstract Surface-enhanced Raman scattering (SERS) remains a significant area of research since it’s discovery 50 years ago. The surface-based technique has been used in a wide variety of fields, most prominently in chemical detection, cellular imaging and medical diagnostics, offering high sensitivity and specificity when probing and quantifying a chosen analyte or monitoring nanoparticle uptake and accumulation. However, despite its promise, SERS is mostly confined to academic laboratories and is not recognised as a gold standard analytical technique. This is due to the variations that are observed in SERS measurements, mainly caused by poorly characterised SERS substrates, lack of universal calibration methods and uncorrelated results. To convince the wider scientific community that SERS should be a routinely used analytical technique, the field is now focusing on methods that will increase the reproducibility of the SERS signals and how to validate the results with more well-established techniques. This review explores the difficulties experienced by SERS users, the methods adopted to reduce variation and suggestions of best practices and strategies that should be adopted if one is to achieve absolute quantification. Graphical Abstract

Abstract The mass production of high-quality graphene is required for industrial application as a future electronic material. However, the chemical vapor deposition (CVD) systems previously studied for graphene production face bottlenecks in terms of quality, speed, and reproducibility. Herein, we report a novel conveyor CVD system that enables rapid graphene synthesis using liquid precursors. Pristine and nitrogen-doped graphene samples of a size comparable to a smartphone (15 cm × 5 cm) are successfully synthesized at temperatures of 900, 950, and 1000 °C using butane and pyridine, respectively. Raman spectroscopy allows optimization of the rapid-synthesis conditions to achieve uniformity and high quality. By conducting compositional analysis via X-ray photoelectron spectroscopy as well as electrical characterization, it is confirmed that graphene synthesis and nitrogen doping degree can be adjusted by varying the synthesis conditions. Testing the corresponding graphene samples as gas-sensor channels for NH3 and NO2 and evaluating their response characteristics show that the gas sensors exhibit polar characteristics in terms of gas adsorption and desorption depending on the type of gas, with contrasting characteristics depending on the presence or absence of nitrogen doping; nitrogen-doped graphene exhibits superior gas-sensing sensitivity and response speed compared with pristine graphene.

Electrode materials comprising SnO2 quantum dots embedded within ZnO hexagonal prisms were successfully synthesized for building cost-effective energy-storage devices. Extensive structural and functional characterizations were performed to assess the electrochemical performance of the electrodes. SEM–EDS results confirm a uniform distribution of SnO2 quantum dots across ZnO. The integration of SnO2 quantum dots with ZnO hexagonal prisms markedly improved the electrochemical behavior. The analysis of electrode functionality conducted in a 3 M KOH electrolyte revealed specific capacitances of 949.26 and 700.68 F g⁻1 for SnO2@ZnO and ZnO electrodes, respectively, under a current density of 2 A g⁻1. After undergoing 5,000 cycles at a current density of 15 A g⁻1, the SnO2@ZnO and ZnO electrodes displayed impressive cycling stability, maintaining specific capacitance retention rates of 89.9 and 92.2%, respectively. Additionally, a symmetric supercapacitor (SSC) device constructed using the SnO2@ZnO electrode showcased exceptional performance, exhibiting a specific capacitance of 83 F g⁻1 at 1.2 A g⁻1. Impressive power and energy densities were achieved by the device, with values reaching 2,808 and 70.2 W kg⁻1, respectively. Notably, the SnO2@ZnO SSC device maintained a capacity preservation of 75% throughout 5,000 galvanostatic charge–discharge sequences. The outcomes highlight the potential of SnO2@ZnO hexagonal prisms as candidates for energy-storage applications, offering scalability and cost-effectiveness. The proposed approach enhances the electrochemical performance while ensuring affordability, facilitating the creation of effective and financially feasible energy storage solutions.

It has been studied that both two-dimensional (2D) MoS2 and V2O5, which are classified as transition metal dichalcogenides and transition metal oxides, are good photocatalyst materials. For this purpose, the hydrothermal method was practiced to synthesize V2O5(1−x)MoS2(x) (X = 1–5% w/w) nanocomposites with different 1–5% w/w weight percent of MoS2 as a prominent photocatalyst under laser irradiation for 2, 4, 6, 8, and 10 min to tune photocatalytic degradation of industrial wastage water. The surface of the 2D molybdenum nanolayered matrix was efficaciously decorated with V2O5 nanoparticles. The crystal phase and layered structures of the V2O5(1−x)MoS2(x) (X = 1–5% w/w) nanocomposites samples were verified by X-ray diffraction and scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy respectively. In the range of the UV visible spectrum, the increment in light absorption from 3.6 to 14.5 Ω−1 cm−1 with an increase of active surface from 108 to 169 μm2{{\rm{\mu }}{\rm{m}}}^{2} with increased MoS2 doping percentage. Furthermore, dielectric findings like the complex dielectric function, tangent loss, electrical conductivity, quality factors, and impedance of V2O5(1−x)MoS2(x) (X = 1–5% w/w) nanocomposites are studied. According to photoluminescence studies, the intensity of peaks decreases when laser irradiation time and doping percentages of MoS2 are increased. As a result, a small peak indicates a decrement rate of electron–hole pair recombination, which increases the capacity for separation. Thermo-gravimetric analysis and differential thermal analysis results revealed that weight loss decreased from 0.69 to 0.35 mg and thermal stability increased with increased doping concentrations. Methylene blue was degraded in 150 min, proving that the prepared MoS2-doped V2O5 material was a stable and economically low-cost nanocomposite for photocatalytic activity.

Abstract The widespread use of polymers has made our lives increasingly convenient by offering a more convenient and dependable material. However, the challenge of efficiently decomposing these materials has resulted in a surge of polymer waste, posing environment and health risk. Currently, landfill and incineration treatment approaches have notable shortcomings, prompting a shift towards more eco-friendly and sustainable biodegradation approaches. Biodegradation primarily relies on microorganisms, with research focusing on both solitary bacterial strain and multi-strain communities for polymer biodegradation. Furthermore, directed evolution and rational design of enzyme have significantly contributed to the polymer biodegradation process. However, previous reviews often undervaluing the role of multi-strain communities. In this review, we assess the current state of these three significant fields of research, provide practical solutions to issues with polymer biodegradation, and outline potential future directions for the subject. Ultimately, biodegradation, whether facilitated by single bacteria, multi-strain communities, or engineered enzymes, now represents the most effective method for managing waste polymers. Graphical Abstract

Abstract Microbial enhanced oil recovery (MEOR) is a cost effective and efficient method for recovering residual oil. However, the presence of wax (paraffin) in residual oil can substantially reduce the efficiency of MEOR. Therefore, microbial dewaxing is a critical process in MEOR. In this study, a bacterial dewaxing agent of three spore-forming bacteria was developed. Among these bacteria, Bacillus subtilis GZ6 produced the biosurfactant surfactin. Replacing the promoter of the surfactin synthase gene cluster (srfA), increased the titer of surfactin in this strain from 0.33 g/L to 2.32 g/L. The genetically modified strain produced oil spreading rings with diameters increasing from 3.5 ± 0.1 to 4.1 ± 0.2 cm. The LadA F10L/N133R mutant was created by engineering an alkane monooxygenase (LadA) using site-directed mutagenesis in the Escherichia coli host. Compared to the wild-type enzyme, the resulting mutant exhibited an 11.7-fold increase in catalytic efficiency toward the substrate octadecane. When the mutant (pIMPpladA2mu) was expressed in Geobacillus stearothermophilus GZ178 cells, it exhibited a 2.0-fold increase in octadecane-degrading activity. Cultures of the two modified strains (B. subtilis GZ6 (pg3srfA) and G. stearothermophilus GZ178 (pIMPpladA2mu)) were mixed with the culture of Geobacillus thermodenitrificans GZ156 at a ratio of 5:80:15. The resulting composition increased the rate of wax removal by 35% compared to the composition composed of three native strains. This study successfully developed a multi-strain bacterial agent with enhanced oil wax removal capabilities by genetically engineering two bacterial strains.

Abstract Superwetting aerogel is a promising alternative for the remediation of emulsified oily wastewater for its high porosity combined with extreme wettability enabled high separation performances to emulsion wastewater. However, it remains challenging for superwetting aerogels to accomplish high-performance dual separation to surfactant-stabilized oil-in-water (O/W) and water-in-oil (W/O) emulsions with high stability. Herein, an environmentally benign superamphiphilic composite aerogel was prepared by a green synthesis route that relied on the utilization of natural amphiphilic biomass. Collagen fibers (CFs) were utilized to construct the three-dimensional (3D) supramolecular skeleton of aerogel to provide high storage capacity of water/oil and outstanding capillary effect to boost the mass transfer. The two-dimensional (2D) lamellar structure of gelatin (Gel) was further grown on the skeleton of CFs aerogel to play the role for simultaneously enhanced demulsifying capability and spreading of emulsions. The as-prepared superamphiphilic aerogel enabled the separation of highly stable surfactant-stabilized O/W and W/O emulsions with high separation efficiency and flux. Excellent recycling performances and anti-fouling performance were also confirmed. Our investigations therefore demonstrated that the structural engineering of superamphiphilic aerogel is a promising way to realize high-performance dual separation of surfactant-stabilized O/W and W/O emulsion wastewater. Graphical Abstract

Abstract The reconstruction of critical-size calvarial defects remains a fundamental challenge. Recombinant collagen has gained significant attention in bone tissue engineering owing to its remarkable bioactivity and non-immunogenicity. Herein, we have for the first time developed a bioactive poly(ethylene glycol)-chondroitin sulfate-triple helical recombinant collagen (PEG-ChS-THRC) hydrogel for enhanced bone regeneration in cranial defects. A simple and mild crosslinking reaction of two-arm polyethylene glycol active ester (NHS-PEG-NHS), adipic dihydrazide modified chondroitin sulfate (ChS-ADH) and triple helical recombinant collagen (THRC) leads to the formation of the PEG-ChS-THRC hydrogel. The hydrogel demonstrates interconnected porous structures, enhanced mechanical strength, diminished swelling ratios and adjustable biodegradability. It possesses exceptional biocompatibility and bioactivity, significantly facilitating cell proliferation, adhesion, migration, and osteogenic differentiation of BMSCs. Micro-computed tomography (micro-CT), magnetic resonance imaging (MRI) and histological characterization of rat models with critical-size cranial defects have consistently demonstrated that the PEG-ChS-THRC hydrogel significantly promotes bone tissues regeneration. The innovative bioactive scaffold provides a remarkably improved remedy for critical-size cranial defects, holding greatly promising applications in the fields of bone tissue regeneration. Graphical Abstract

Abstract The global scenario on PVC plasticizer is experiencing a drastic change from petroleum-based, toxic di-(2-ethylhexyl) phthalate (DEHP) toward renewable, non-toxic bio-alternatives. However, replacing diisodecyl phthalate (DIDP), a DEHP analogue specifically intended for plasticizing PVC automotive upholstery, with bio-alternative remains a challenge as few bio-plasticizer volatilizes from PVC as slowly as DIDP, a crucial aspect compulsorily required by automotive industry. Here, we demonstrate that covalently attaching two short esters at the α-position of all components of a traditional epoxidized fatty acid methyl ester via a two-step, hydrogen-to-ester nucleophilic substitution in a one-pot procedure yields an epoxidized fatty acid tri-ester bio-plasticizer with remarkably suppressed volatilization from PVC, and hence an extremely low fogging value comparable to DIDP. With this strategy in hand, DIDP, long deemed irreplaceable despite its toxicity and non-renewable nature, may ultimately be phased out. Graphical Abstract

Abstract Astaxanthin biosynthesis in Haematococcus pluvialis is driven by energy. However, the effect of the flagella-mediated energy-consuming movement process on astaxanthin accumulation has not been well studied. In this study, the profiles of astaxanthin and NADPH contents in combination with the photosynthetic parameters with or without flagella enabled by pH shock were characterized. The results demonstrated that there was no significant alteration in cell morphology, with the exception of the loss of flagella observed in the pH shock treatment group. In contrast, the astaxanthin content in the flagella removal groups was 62.9%, 62.8% and 91.1% higher than that of the control at 4, 8 and 12 h, respectively. Simultaneously, the increased Y(II) and decreased Y(NO) suggest that cells lacking the flagellar movement process may allocate more energy towards astaxanthin biosynthesis. This finding was verified by NADPH analysis, which revealed higher levels in flagella removal cells. These results provide preliminary insights into the underlying mechanism of astaxanthin accumulation enabled by energy reassignment in movement-lacking cells.

Natural fibre-reinforced polymer composite (NFRPC) has been introduced as one of the solutions to overcome the ecological and environmental problems accompanying the widespread usage of polymeric materials in every facet of life. However, the organic nature of both natural fibres (NFs) and polymers increases their flammability behaviour, and this, in turn, limits their application. In this regard, this work concentrates on studying the effect of adding flame retardants (FR) to jute-reinforced epoxy composites (JRECs), either by treating the jute fabric with diammonium phosphate (DAP) or adding DAP powder to the epoxy resin matrix on the flame retardancy performance as well as the mechanical properties. The results showed that the effect of the incorporation method of DAP either to jute fabric or to resin matrix has a significant difference on the flammability test results at low concentrations; however, at higher concentrations, the flame retardancy performance is not affected by the technique of adding FR to the composite system. On the other hand, the mechanical properties are significantly affected by the method of incorporating FR to JRECs at all concentrations. Moreover, the results obtained from JRECs with FR systems were evaluated and compared with the literature by constructing selection charts that relate the flame retardancy level to mechanical properties.

Nanomaterials, particularly nanofibers produced through electrospinning, have garnered significant attention due to their unique properties and diverse applications. This research explores the influence of collector design, electrode geometry, and collector speed on the properties of electrospun polyacrylonitrile (PAN) nanofibers. Finite element analysis (FEA) was employed to simulate electric fields, revealing the impact of collector geometry on field intensity. The experimental setup, enclosed in an isolated chamber, employed various collector types and electrode configurations. Scanning electron microscope (SEM) analysis showcased the effect of collector speed on fiber alignment and diameter. Furthermore, FEA simulations elucidated the role of electrode geometry and voltage in shaping the electric field, impacting fiber properties. The study introduces a novel, in-house method for producing highly aligned nanofibers and provides insights into optimizing electrospinning parameters for enhanced fiber properties. A testing protocol is devised to minimize surface damage when conducting mechanical tests on nanofiber films, employing a dynamic mechanical analyzer (DMA). Mechanical testing demonstrated the correlation between alignment and tensile strength. Overall, this research contributes valuable insights for tailoring electrospinning processes for tissue engineering and energy storage.

The drastic increase in the amount of packaging waste from conventional plastics, caused by improper waste management, is a serious challenge for the planet. It is therefore worth considering how we can solve this problem. Thus, it is necessary to develop new polymeric materials that retain the functional properties of traditional plastics but are susceptible to degradation with the participation of microorganisms. The development of new eco-friendly materials requires a holistic approach in terms of their disposal. Organic recycling enables the disposal of biodegradable packaging along with food remains that are difficult to remove. The article presents a study on the degradation of biocomposites of polylactide with cork in various environments (water, buffer, and compost). The obtained results indicate a clear influence of the presence of the filler and its amount on the degradation profile of the composites. In addition, the effect of sample shrinkage was observed, especially during degradation in water, where the pH decreases during the process due to the appearance of degradation products. This effect may be important not only for the degradation profile of the packaging but also during its use. Packaging distorted due to shrinkage may be a sign of improper product storage.

Thermoplastic polyurethanes (TPU) have attracted increasing attention due to their excellent flexibility, chemical stability, processability and greenness. The traditional processes generally limit them to civil and industrial applications, but electrospun TPU nanofibers with high porosity, high specific surface area and superior mechanical properties are promising in emerging fields. TPU nanofibers’ properties are affected by various electrospinning parameters, such as solution concentration, applied voltage, flow rate and rotational speed. Thus, 29 sets of experiments were designed here by the efficient and low-cost response surface methodology (RSM). The analysis of variance (ANOVA) revealed that the model agrees well with experimental results, and solution concentration is the most crucial parameter affecting nanofibers’ morphology and diameter. Based on it, the impacts of solution concentration and orientation on the mechanical properties of the TPU nanofiber membrane were investigated. Benefiting from the stress transfer and network deformation, the TPU nanofiber membranes parallel to the collection direction possessed the highest stress strength (23.71 MPa), while the nanofiber membranes vertical showed the widest strain range (485%). This study provides useful guidance for the preparation of high-performance TPU nanofibers, contributing to expanding its applicability in emerging fields such as biomedical, filtration and separation, and flexible sensing.

The protein from black soldier fly larvae was used as a functional ingredient of a novel green nanofiber. Larvae protein powder (LP) was blended with biodegradable poly(ε-caprolactone) (PCL) and processed in an electrospinning machine using a coaxial feeding/mixing method to produce nanofibers approximately 100–350 nm in diameter. To improve the dispersion and interface bonding of various PCL/LP nanofiber components, a homemade compatibilizer, maleic anhydridegrafted poly(ε-caprolactone) (MPCL), was added to form MPCL/LP nanofibers. The structure, morphology, mechanical properties, water absorption, cytocompatibility, wound healing, and biodegradability of PCL/LP and MPCL/LP nanofiber mats were investigated. The results showed enhanced adhesion in the MPCL/LP nanofiber mats compared to PCL/LP nanofiber mats; additionally, the MPCL/LP nanofibers exhibited increases of approximately 0.7–2.2 MPa in breaking strength and 9.0–22.8 MPa in Young’s modulus. Decomposition tests using a simulated body fluid revealed that the addition of LP enhanced the decomposition rate of both PCL/LP and MPCL/LP nanofiber mats and in vitro protein release. Cell proliferation and migration analysis indicated that PCL, MPCL, and their composites were biocompatible for fibroblast (FB) growth. Biodegradability was tested in a 30 day soil test. When the LP content was 20 wt%, the degradation rate exceeded 50%.