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As a solid waste from steel making, steel slag can be recycled to replace natural aggregates (NA) for developing steel slag aggregate (SSA) concrete, an environmentally friendly construction material. In order to evaluate the effect of steel slag on the permeability of SSA concrete, which may have a potential impact on the structure durability, this study presented a multi-scale finite element (FE) method for investigating the seepage process and mechanism inside the SSA concrete. The above FE method consisted of a microscale mortar model and a mesoscale concrete model, developed by integrating image processing technique and random aggregate method. The permeability coefficient of SSA concrete was evaluated with the above multi-scale FE method and was validated with experiment. The relative differences between the numerical simulation and experimental mean values of the permeability coefficients are 3.38∼5.94 %. Based on the validated method, the effects of steel slag on the seepage characteristics of concrete were analyzed. Results show that the incorporation of steel slag could decrease the permeability of concrete by reducing the mortar porosity in the microscale and reducing the thickness of the interfacial transition zone (ITZ) between aggregate and mortar in the mesoscale. Using over-simplified aggregate shapes in numerical simulation may underestimate the permeability coefficient of concrete, which emphasizes the importance of refined modelling. The permeability coefficient of concrete may exhibit anisotropy. When considering lateral water permeation, aggregates with aspect ratios close to one may offer superior resistance to seepage. The analysis findings provide insights for better material design of concrete with recycled materials. • Developed and validated multi-scale model of concrete containing steel slag aggregate for prediction of permeability. • Measured permeability of concrete and aggregate and observed interfacial transition zone of concrete using microscopy imaging. • Analyzed effects of steel slag on seepage characteristics and permeability of concrete. [ABSTRACT FROM AUTHOR]

• The FDTD simulation reveals the phenomenon that the absorber has a large bandwidth with high absorptivity and two resonance absorption peaks in the mid-long infrared band, which indicates that the absorber has absorption selectivity. • By changing the geometric structure parameters of the absorber, the absorptivity of the absorber in the middle and long infrared band is adjusted. • The polarization insensitivity and Angle independence of the absorber are determined by simulating the absorption characteristic curves of the absorber at different incident angles and polarization modes. • By adding different kinds of metals and media types, comprehensive selection of better performance combination, to meet our needs. Infrared band occupies a very important position in the electromagnetic wave band. Traditional infrared devices use the inherent properties of natural materials to achieve the regulation of electromagnetic waves, but the limited ability of such devices to regulate electromagnetic waves can't well meet our needs. In this paper, we reported a metamaterial absorber of Cr-Si 3 N 4 -Cr-Si 3 N 4 -Ti based on double-layer metal-insulator-metal (MIM). It is investigated with the optimal structural parameters of 490 nm, 330 nm, 30 nm, 720 nm, 120 nm, in descending order, at which the absorptive properties are studied. When the light wave is incident vertically, it can be obtained from the experimental simulation that this absorber has polarisation insensitivity. Because of the coupling effect of the surface plasmon resonance and the high-loss material, the bandwidth of absorption greater than 90% can reach 9190 nm, and the average absorption in the target long-wave infrared band (9.506∼18.145 μm) is 94.8%. By selecting different geometrical parameters of the structure, the absorption spectrum can be adjusted independently. In addition, the absorber has good incident angle insensitivity in TE and TM modes. Also, the absorber we proposed has a plain structure, is convenient for manufacturing, the material is easier to obtain, which ensures a good absorption bandwidth and average absorptivity, and the study of this metamaterial absorber has important applications in solar cells, satellite radiothermographs, photodetectors, and spectral imaging. In this work, we simulate and calculate the performance of a broadband absorber based on a double-layer MIM structure. The results show that the absorber can achieve an average absorption of 90% in the range of 9.48–18.67 μm and 94.8% in the targeted longwave infrared band (9.506–18.145 μm). In response to the broadband absorption, we designed the schematic structure of the absorber based on the MIM (metal-dielectric-metal) structure. The structure of each cell is composed of a two-layer MIM structure, from top to bottom, Cr, Si 3 N 4 ,Cr,Si 3 N 4 ,Ti.The simulation results show that two resonant modes are generated at 10.25μm and 16.75μm, and the absorption rates are 98.9% and 99.3%, respectively. Then, the geometric parameters of the structure are adjusted respectively to get the best parameter values. In addition, the comparison of several different microstructures proves the advantages of our designed structure. We also simulate the absorption characteristic curves at different incidence angles and different polarization modes. Finally, we compare by changing the type of metal and medium. To sum up, the absorbers designed by us have the characteristics of broadband high absorptivity, no relation between polarization and incidence Angle, and simple structure. [Display omitted] [ABSTRACT FROM AUTHOR]

Random fields are widely used to represent the uncertainty of some parameters in engineering, and numerous simulation approaches have been developed for Gaussian and non-Gaussian random fields. However, the unified methods among them suffer from low computational accuracy and efficiency or discontinuities in the simulated random fields. Therefore, an easy-to-implement general simulation method based on the active learning Kriging model is proposed for a one dimensional(1D) Gaussian or non-Gaussian random field in this paper. In the proposed method, there are two stages. One stage, called the inner loop, is to construct the Kriging approximation of a random field sample with enough accuracy by some samples of the random variables at some discretized locations, in which an active learning strategy based on the error estimation for the Kriging model is introduced to select adaptively the added locations, and a fast sampling method is presented to determine efficiently the samples at the added locations. In the other stage, called the outer loop, some random field samples are represented accurately by their corresponding Kriging approximations through training iteratively. Furthermore, several numerical examples are presented to show the accuracy, effectiveness and generality of the proposed method for 1D Gaussian and non-Gaussian random fields by comparing with the Karhunen–Loève(KL) expansion method. Meanwhile, the effects of the types of correlation function and the scales of fluctuation on the simulation results are analyzed. [ABSTRACT FROM AUTHOR]

ZIF-8, a sort of zeolitic imidazolate frameworks (ZIFs), had showed superior adsorptive property of typical radionuclide U(VI), but it reminded uncertain how the performance of ZIF-8 would be affected by adding humic acid (HA). HA could significantly change the surface charge of ZIFs and the transport of U(VI) in natural settings, which affected the eradication of U(VI) in aquatic ecology. Thus the impact of HA for the U(VI) removal by ZIF-8 as well as its mechanism had been analyzed by batch experiments and spectral analyses. It was demonstrated that the addition of HA increased the maximum removal capacity towards U(VI) from 781.2 mg g−1 to 1398.5 mg g−1. Moreover, removal property in acidic solution was improved, and the influence of background ions on ZIF-8 was reduced. The detailed mechanism was further explored by microscopic spectral analysis. The zeta potential showed that HA enhanced the electronegativity of ZIF-8 thus enhancing the electrostatic interaction with positive ions. Moreover, FT-IR and XPS further indicated that HA enhanced the removal capacity by affecting the surface complexation phenomena and strong chemical interactions between U(VI) and ZIF-8. Also, investigations indicated that the incorporation of HA improved the removal efficiency for U(VI), which had far-reaching significance for the application of ZIF-8 in practical environment. [Display omitted] • The effect of humic acid on the physicochemical properties of ZIF-8 was studied. • A fresh thinking for future research in practical application are prompted. • The influence of HA on the adsorption of uranium by ZIF-8 was studied. • The mechanisms are surface complexation and electrostatic interactions. • HA as a natural substance is more environmentally friendly in wastewater treatment. [ABSTRACT FROM AUTHOR]

Uranium mainly exists in the form of uranyl carbonate in seawater. [UO 2 (CO 3) 3 ]4- has strong stability, which increases the difficulty of uranium extraction from seawater. Meanwhile, the complex marine environment, a large number of coexisting competing ions and biological pollution are all non-negligible disturbing factors. Herein, we introduced amidoxime (AO) groups into the surface of Ti 3 C 2 and grafted polyamides (PA) by a simple one-step hydrothermal method to produce an efficient seawater uranium extraction adsorbent Ti 3 C 2 -AO-PA. Owing to the amidoxime groups, the material was highly selective for uranium. And the large number of amino groups in the polyamides gave it ideal resistance to biofouling. The possibility of Ti 3 C 2 -AO-PA as an adsorbent for uranium extraction from seawater was confirmed by various characterization techniques, numerous adsorption batch experiments, simulated seawater experiments and antibacterial performance tests. It was demonstrated that the uptake of [UO 2 (CO 3) 3 ]4- by Ti 3 C 2 -AO-PA showed fast reaction kinetics (about 120 min), brilliant absorption capacity (81.1 mg·g−1 at pH 8.3), significant high selectivity (32.8 mg-U/g-Ads) and outstanding anti-biological contamination performance (92.9% antibacterial rate). XPS and DFT further indicated that the high extraction ability of Ti 3 C 2 -AO-PA for uranium was mainly attributed to the strong complexation of AO and –NH 2 with [UO 2 (CO 3) 3 ]4-. These conclusions showed that Ti 3 C 2 -AO-PA not only had an ideal application prospect for uranium extraction from seawater, but also provided an available strategy for rapid and selective uranium adsorption from real seawater. [Display omitted] • Polyamide enhanced amidoxime-functionalized Ti 3 C 2 nanosheet was constructed. • The uranium extraction capacity was highly enhanced. • Ti 3 C 2 -AO-PA showed excellent selectivity and antimicrobial properties. • Synergistic interactions of amidoxime and polyamide with uranium ions in seawater. [ABSTRACT FROM AUTHOR]

The potential threat of radionuclide uranium from nuclear industry had attracted worldwide attention because both environment and human beings were menaced. Nowadays, modified nanoscale zero valent iron (NZVI) had been reported to be efficient in U(VI) elimination due to its high reactivity, reducibility, and availability. In this study, serial biochar-based sulfide NZVIs (BC-SNZVIs) with different C/Fe and S/Fe were synthesized and applied to the elimination of U(VI) in order to investigate the effect of iron, sulfur, and biochar precursor. The morphological investigations indicated the precursor played an essential role towards BC-SNZVIs on their dispersibility and structure. The XRD analyzes were conducted to study their crystalline structure and the BC 1.0 -S 0.14 NZVI showed outstanding stability after 10-day exposure under atmosphere. The excellent magnetism was confirmed via VSM study, and BC 1.0 -S 0.14 NZVI could be easily and rapidly separated from aqueous solution. The batch kinetic and isothermal studies illustrated the superior performances towards U(VI), and the results revealed the fast kinetics and high capacities of BC-SNZVIs. Finally, the removal mechanism was explored by using XPS technology and pH-effect experiment. U(VI) was adsorbed by BC matrix and SNZVI, while portion of U(VI) was reduced into U(IV) by Fe0 inner core. The elimination process of U(VI) towards BC-SNZVI was confirmed to be a synergistic effect of adsorption and reduction. This study verified the optimal ratio of C/Fe and S/Fe, and explained the removal mechanism in detail, which was beneficial to further investigations of NZVI-based and biochar-based materials. [Display omitted] • The impact of C/Fe and S/Fe ratios on biochar-based SNZVIs were investigated. • BC 1.0 -S 0.14 NZVI showed excellent attraction and outstanding performance to U(VI). • The removal mechanism was a synergistic effect of reduction and adsorption. [ABSTRACT FROM AUTHOR]

Because the pollutants produced by human activities have destroyed the ecological balance of natural water environment, and caused severe impact on human life safety and environmental security. Hence the task of water environment restoration is imminent. Metal-organic frameworks (MOFs), structured from organic ligands and inorganic metal ions, are notable for their outstanding crystallinity, diverse structures, large surface areas, adsorption performance, and excellent component tunability. The water stability of MOFs is a key requisite for their possible actual applications in separation, catalysis, adsorption, and other water environment remediation areas because it is necessary to safeguard the integrity of the material structure during utilization. In this article, we comprehensively review state-of-the-art research progress on the promising potential of MOFs as excellent nanomaterials to remove contaminants from the water environment. Firstly, the fundamental characteristics and preparation methods of several typical water-stable MOFs include UiO, MIL, and ZIF are introduced. Then, the removal property and mechanism of heavy metal ions, radionuclide contaminants, drugs, and organic dyes by different MOFs were compared. Finally, the application prospect of MOFs in pollutant remediation prospected. In this review, the synthesis methods and application in water pollutant removal are explored, which provide ways toward the effective use of water-stable MOFs in materials design and environmental remediation. [Display omitted] • The synthesis strategies of water-stable MOFs are briefly introduced. • The mechanisms mainly ascribe to coordination and electrostatic interaction. • Sufficient functional groups endow MOFs excellent performance. • Multi-factor influences demonstrate the practical application potential of MOFs. [ABSTRACT FROM AUTHOR]

• Lateral instability modes of vehicles on horizontal curves are discovered. • Boundary of each stability index is derived through calculation and analysis. • A theoretical framework for realizing a revised inferred design speed is established. • Previous speed limit strategies cannot fully guarantee the safety of driving. • Considerations in the application of the proposed method are demonstrated. An inferred design speed (IS) is the maximum vehicle speed for which all critical design speed-related criteria are met at a particular location, which is widely recognized as an important speed limit on highways. However, a side friction factor is used as an index for vehicle lateral stability in the calculation of IS for horizontal curves. This condition causes inaccuracies in the value of IS due to the incapability of the index in fully characterizing the steering stability and track-holding capability of vehicles. This paper aims to fill this gap by discovering the lateral instability modes of vehicles on horizontal curves and to determine the boundary of each index beyond which the corresponding mode of instability occurs. Thus, a theoretical framework for realizing a revised IS (RIS) was established. A high-precision seven-degree-of-freedom driver–vehicle–road mathematical model was developed using MATLAB/Simulink. The state of vehicle lateral instability on highway horizontal curves was decoupled, and the boundaries of vehicle stability indices were deduced using the theory of vehicle system dynamics. Accordingly, a procedure for determining RIS was proposed. Case studies were conducted on the three horizontal curves of a two-lane rural highway in China, and existing speed limit methods were compared with RIS. With in-depth consideration of the lateral instability characteristics of vehicles, RIS provides traffic management departments with a precise maximum safe speed on horizontal curves under various pavement friction conditions. It is expected to be a restriction with respect to safety for other speed limit strategies that consider driver expectancy and efficiency. [ABSTRACT FROM AUTHOR]

Bacteria may change the physicochemical properties of montmorillonite and further effect the disposal of high-level radioactive waste. Therefore, we explored the influence of Shewanella oneidensis MR-1 on the elimination of representative radionuclide U(VI) by montmorillonite (MMT). The batch experiments showed that MR-1 significantly enhanced the removal efficiency of U(VI), the adsorption capacity of MMT improved from 8.4 to 16.1 mg/g after addition of MR-1, and the adsorption type changed from Langmuir to Freundlich. FTIR and XPS analysis revealed that hydroxyl, phosphate, carbonyl and amine in MMT + MR-1 were primary actors in the elimination of U(VI). The U 4f high-resolution XPS spectrum of MMT + MR-1 showed U(VI) and U(IV) peaks at the same time, indicating that the adsorption process was accompanied by the reduction reaction, which may be due to the extracellular respiration of MR-1. These investigations are significant to insight the potential significance of microbial processes for the transport and elimination of U(VI) in repositories, which in return will contribute to their safe disposal. [Display omitted] ● Synergetic effect existed in U(VI) sequestration onto MMT + MR-1. ● Shewanella oneidensis MR-1 enhanced the elimination of U(VI) on montmorillonite. ● The adsorbed U(VI) can be reduced to U(IV) by Shewanella oneidensis MR-1. ● The main mechanisms between U(VI) and MMT + MR-1 were adsorption and reduction. [ABSTRACT FROM AUTHOR]

Both environment and human beings were menaced by the widespread application of radioactive uranium, high-performance and effective elimination of uranium from wastewater is of important meaning for development of environmental sustainability in the future. In this study, the water-stable MOF material and the highly crystalline COF were compounded by a mild hydrothermal strategy, which achieved efficient removal of U(VI) through the synergistic effect. The composites showed the characteristics of both COFs and MOFs, which will possess higher stability, larger surface area and faster adsorption efficiency that cannot be carried out by a single component. Batch experiments and characterizations (SEM, TEM, XRD, FT-IR, BET, XPS, etc.) indicated that UiO-66-NH 2 @LZU1 had more stable and multi-layer pore structure and rich active functional groups. The Langmuir model and the pseudo-second-order kinetics fitting was more suitable for the U(VI) elimination process. The greatest uranium adsorbing capacity of UiO-66-NH 2 @LZU1 (180.4 mg g−1) was observed to exceed the UiO-66-NH 2 (108.8 mg g−1) and COF-LZU1 (65.8 mg g−1), which reached the excellent hybrid effects. Furthermore, FT-IR and XPS analyses confirmed that the most nitrogen-containing group from COF-LZU1 and oxygen-containing group of UiO-66-NH 2 could be combined with U(VI). In addition, electrostatic interaction was also a mechanism during the removal process. This work displayed that UiO-66-NH 2 @LZU1 was a prospective hybrid material for radioactive waste remediation. The compound method and application mentioned in this work had provided a theoretical basis for designing and developing multi-functional composite adsorbents, which contributed to the development of new materials for radioactive wastewater treatment technologies. [Display omitted] • UiO-66-NH 2 @LZU1 composite material was obtained by solvothermal method. • Highly efficient uranium adsorbent, adsorption capacity reached 163.1 mg g−1. • Abundant nitrogen/oxygen functional groups promote uranium removal. • Main removal mechanism included electrostatic interaction and surface complexation. [ABSTRACT FROM AUTHOR]

With the advantages of high atomic utilization, clear and uniform active sites, high catalytic activity, outstanding stability, excellent selectivity and recyclability, iron single-atom materials have shown promising application in the fields of electrocatalysis, hydrogen production, batteries, and sensors. However, the research work on the efficient removal of various toxic and hazardous pollutants from aqueous solutions using iron single-atom materials was still limited. Their properties such as environmental compatibility, high specific surface area and functionality have unrivaled natural advantages in degrading pollutants in aqueous solutions, which deserve in-depth exploration by researchers. However, pure single-atom materials were thermodynamically unstable and tended to aggregate into nanoclusters and particles. Therefore, single-atom materials were often loaded onto different support materials, while the activity of materials depended mainly on the physicochemical properties of the support materials and the coordination mode between the single-atoms and the support materials. In this review, the preparation and physicochemical properties of iron single-atom materials supported by commonly used carrier materials (such as g-C 3 N 4 , MOFs, COFs, biochar, etc.) were summarized firstly. The applications of different materials for organic pollutants degradation and heavy metal ions removal in aqueous environment were further analyzed, and influence factors and reaction mechanisms for pollutants treatment were investigated. The main mechanism of organic pollutants degradation was catalytic degradation, while the mechanism of heavy metal ions removal was adsorption and redox. Finally, prospects and personal insights were provided for the utilization of iron single-atom materials in environmental pollution decontamination. [Display omitted] • The preparation and properties of iron single-atom materials are summarized. • The influencing factors of removing environmental pollutants are introduced. • The mechanisms mainly include catalytic degradation, adsorption and redox. • The possible degradation pathways of typical pollutants are predicted. • The opportunities and challenges of iron single-atom materials are presented. [ABSTRACT FROM AUTHOR]

Radioactive uranium removal plays a key role in energy development and environmental security. Sulfide nanoscale zero-valent iron (S-NZVI) has good antioxidant capacity, dispersibility and activity to eliminate U(VI) from wastewater, but the removal efficiency is limited. To improve the reduction and adsorption capacity of S-NZVI, through treating Fe3+ solution by nitro-functionalized UiO-66 (UiO-66-NO 2) with high porosity, UiO-66-NO 2 enhanced S-NZVI adsorbent (S-NZVI/UiO-66) was prepared by liquid phase reduction method. The smaller size and larger specific surface area of S-NZVI/UiO-66 were confirmed by a variety of characterization techniques. Based on the excellent surface structure and reactivity, the U(VI) removal capacity of S-NZVI/UiO-66 (895 mg g−1) was much better than S-NZVI (434 mg g−1) and UiO-66-NO 2 (267 mg g−1). The impacts of pH, background ion strength, coexisting ions and different water environments on adsorption were studied via macroscopic batch experiments. The results showed that S-NZVI/UiO-66 could remove U(VI) adequately in a wide pH range. The removal rate was basically not affected by the concentration of NaNO 3 , demonstrating that the adsorption process of U(VI) on S-NZVI/UiO-66 tended to inner surface complexation. From XPS technique combined with the results of batch adsorption experiments, it was clear that the elimination mechanisms of U(VI) by S-NZVI/UiO-66 were mainly the physical adsorption, electrostatic attraction and complexation of UiO-66-NO 2 , and the reduction and complexation of S-NZVI. Therefore, it is believed that S-NZVI/UiO-66 has a great potential to be an excellent adsorbent in the field of the environment remediation. Moreover, S-NZVI/UiO-66 promises to be a novel nanomaterial for solving the problem of radionuclide contamination in practical environments. [Display omitted] • The pretreatment of UiO-66-NO 2 can effectively reduce the size of S-NZVI. • S-NZVI/UiO had a better specific surface area than the original S-NZVI. • The practical application potential of S-NZVI/UiO was confirmed. • The removal mechanisms were adsorption and reduction. [ABSTRACT FROM AUTHOR]

Electrical and electronic equipment (EEE) that greatly enhances global living standards has become indispensable in modern societies. In EEE, most electronic devices are protected by epoxy electronic packaging that exhibits outstanding mechanical property, high electrical resistivity and excellent solvent resistance. However, due to thermolability of electronic components and insolubility of epoxy, it is impossible to heal and recycle the packaged electronic devices non-destructively, resulting in a huge amount of e-waste during manufacturing and consumption. Herein, aromatic disulfide epoxy vitrimer packaged electronic devices were proposed, in which nondestructive healing and recycling were achieved. The epoxy vitrimer was prepared from aromatic disulfide-based epoxy and aliphatic amines at moderate temperature (≤100 °C), resulting in highly cross-linked networks, excellent solvent resistance and good thermal stability. The tensile strength was ∼71.9 MPa and the glass transition temperature was ∼115 °C. Moreover, it exhibited comparable electrical resistivity to reference epoxy, while lower dielectric constant was observed. In epoxy vitrimer packaged LED light, cracks could be readily healed at 150 °C through aromatic disulfide metathesis in networks, while the epoxy vitrimer exhibited topology freezing transition at ∼118 °C. Besides, relying on reactions between aromatic disulfide bonds and outer thiol groups, the epoxy vitrimer packaged LED light, printed circuit board and integrated circuit could be non-destructively recycled, while the epoxy vitrimer was degradable on demand. The aromatic disulfide epoxy vitrimer packaged electronic devices with nondestructive healing and recycling properties provide a better way to deal with substandard electric products and retired ones, leading to e-waste reducing, resource recycling and environment-friendly development in EEE. [Display omitted] • An aromatic disulfide epoxy vitrimer that reacted at moderate temperature was prepared to package electronic devices. • The epoxy vitrimer packaged electronic devices exhibited nondestructive crack-healing properties. • The epoxy vitrimer packaged LED light, printed circuit board and integrated circuit were non-destructively recycled. [ABSTRACT FROM AUTHOR]

Vitrimers, a new generation of polymeric materials, have been widely investigated to resolve the intersection of thermoplastics and thermosets, relying on the exchange reactions in networks. However, it is still a challenge to develop multi-functional vitrimer materials. Herein, multi-functional epoxy vitrimers that exhibited controllable dynamic properties, multiple-stimuli response, crack-healing and fracture-welding were prepared by introducing Fe 3 O 4 nanoparticles into the networks of dual dynamic epoxy vitrimers. It was revealed that the typical dynamic parameters of vitrimer including the characteristic relaxation time (τ), activation energy (E a), Arrhenius prefactor (τ 0) and topology freezing transition temperature (T v) could be readily adjusted in the multi-functional epoxy vitrimers. Moreover, the multi-functional epoxy vitrimers were simultaneously responsive to temperature, near infrared and magnetic field, while they could be driven by magnets, heated by near infrared and healed or welded by heating. Upon heating or near infrared, the cracks in samples could be successfully healed. Besides, by the cooperation of heating and magnet or near infrared and magnet, the multi-functional epoxy vitrimers were able to achieve non-touch welding of factures. These multi-functional epoxy vitrimers might have potential application in improving the reliability and extending the lifetime of polymeric materials. Meanwhile, the facile way to functionalize the epoxy vitrimers is estimated to be suitable for other vitrimer materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Toxic metals and organic pollutants have become serious environment issues because these contaminants can cause indelible damage to human health and aquatic organism. Various materials have shown great potential in removing conventional contaminants and purifying water. Among them, carbon nanofibers (CNFs) have been regarded as promising candidates in the purification of water environments, owing to their distinct physical/chemical properties, but the connection between properties of CNFs and their removal performance receives few attentions. In this systematic review, we summarize the recent processes in synthetic strategies of CNFs, and highlight their water environmental applications via multiple interactions (π-π interaction, electrostatic interaction, and surface complexation). Some challenges and future outlooks of CNFs materials are briefly discussed. The content presented here will provide a helpful reference value for promoting the development of CNF-based nanomaterials and comprehend the significance of purifying water environments and protecting nature from pollutants. [Display omitted] • Abundant functional groups of carbon nanofibers promote water purification. • Surface modification and composite materials improve the removal performance. • Metal ions are removed via electrostatic interaction and surface complexation. • Organic contaminants are eliminated by π-π interaction and hydrophobic interaction. [ABSTRACT FROM AUTHOR]

Radioactive pollutants have always been the top priority in wastewater, and searching a green and efficient treatment technology remains a significant challenge. In this study, a novel melamine sponge supported sulfurized nanoscale zero-valent iron (MS@S-NZVI) material with high dispersion was firstly designed to effectively capture U(VI) from water environment. The target material could retain its original structure in water due to the excellent mechanical strength of MS, which greatly inhibited the aggregation of S-NZVI. A series of characterization techniques, such as SEM, XRD, FTIR, TGA and XPS, had proved the effective synthesis and excellent structural properties of the MS@S-NZVI. The faster reaction equilibrium (<1 h) and higher maximum adsorption capacity (180 mg/g at pH = 5 and 298 K) exposed the perfect performance of target material in the elimination of U(VI). In addition, further researches in different water systems exhibited that MS@S-NZVI had a significant U(VI) removal rate in simulated wastewater systems. Finally, the removal process of MS@S-NZVI to U(VI) could be divided into three pathways through the XPS technique, adsorption and reduction were the main reaction mechanisms. This study provides a new insight into the utilization of melamine sponge and a prospect for the practical application of S-NZVI in the removal of radionuclide. [Display omitted] • Melamine sponge was used to support S-NZVI for the first time. • The structure of sponge enabled MS@S-NZVI to disperse fully in water. • The practical application potential of MS@S-NZVI was confirmed. • Adsorption and reduction were the main reaction mechanisms. [ABSTRACT FROM AUTHOR]

In this paper, nanoscale zero-valent iron (NZVI), which has great potential in environmental purification is introduced. However, NZVI is easy to accumulate and oxidize, which limits its ability to remove pollutants. Hence several modified NZVI are proposed to overcome its shortcomings in this paper. The heavy metal ions, radionuclides and organic pollutants in the environment are removal by NZVI based materials, and their removal behaviors had been analyzed. This paper also reviews the factors affecting the removal of pollutants by NZVI-based materials, such as pH, ionic strength, contact time, reaction temperature, interfering ions and humic acids. In addition, it is also introduced that NZVI is toxic in the environment, and it also can be recovered and has different removal effects in different water environment. In short, this paper gives a comprehensive summary of NZVI, including its modification methods, pollutants removal, influencing factors of pollutants removal and implication to environment. It provides a strong theoretical basis for the future development of NZVI based materials. [Display omitted] • The characteristics of NZVI-based materials are briefly introduced and summarized. • The removal mechanisms of different pollutants are highlighted. • The influence factors and environmental implications are analyzed. • Future researches of NZVI-based materials in water remediation are discussed. [ABSTRACT FROM AUTHOR]