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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]

Graphical abstract Highlight • LDH@nZVI composite was prepared via a facile and green method. • Synergistic effects improved the capture ability for U(VI) on LDH@nZVI than single-guest. • O and Fe functional groups play an important role in the immobilization process of U(VI). • Interaction mechanism between U(VI) and LDH@nZVI was adsorption and reduction. Abstract In this study, nanoscale zero-valent iron (nZVI) supported on layered double hydroxide (LDH) composite (LDH@nZVI) was prepared, characterized and applied to U(VI) scavenging in water. Removal of U(VI) as a function of pH, ionic strength, reaction time, initial concentrations of U(VI), and temperature were studied and compared with pure LDH and nZVI, the LDH@nZVI had best U(VI) removal efficiency owning to the excellent synergistic combination of LDH adsorption and nZVI reduction. XPS analysis found that surface oxygen functional groups and surface-bound Fe(II) played a critical role in U(VI) remediation. The large surface areas (334.0 m2/g), abundant functional groups (i.e., M O, C O and OH), rapid kinetics (adsorption equilibrium within 1 h) and excellent adsorption capacities (176 mg/g) indicating that LDH@nZVI can be considered as a potential material for preconcentration of U(VI) from sewage water. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • CMN and CCMN were prepared via a single-step hydrothermal technique and calcination process. • The maximal removal capacities of U(VI) on CMN and CCMN were 585.6 and 973.7 mg/g, respectively. • Metal-oxygen functional groups played an important role in the elimination of U(VI). • Interaction mechanism was attributed to strong inner-surface complexation. Abstract Uranium is considered to be a strategic means for the nuclear power as well as a worldwide highly toxic pollutant. For the enhanced U(VI) elimination from wastewater, novel Co-Mo-Ni ternary hydroxide (CMN) and calcined CMN (CCMN) nanocomposites were prepared via a simplistic single-step hydrothermal technique and calcination process. The elimination process and adsorption property of U(VI) on CMN and CCMN were analysed by batch experiment as well as spectroscopy analysis, and the researches showed that U(VI) was formed stable and strong complexes with the surface groups of CMN and CCMN. The maximal removal capacities of U(VI) on CMN and CCMN amounted to be 585.6 and 973.7 mg/g at pH = 5.0 and T = 298 K, correspondingly, that exhibited competitiveness with the majority of the reported adsorbents. The U(VI) uptake was substantially impacted by the tested solution pH and not affected by the ionic strength, which revealed that the interaction mechanism was primarily inner-sphere surface complexation, which received further confirmation by the XPS analysis. Based on the above analyses, the facile synthesis process and excellent U(VI) elimination performance denoted that the ternary (hydr)oxide materials were applicable as an attractive adsorbent for the radionuclides preconcentration and removal from aqueous solutions in natural environmental management. [ABSTRACT FROM AUTHOR]

Water pollution, a worldwide issue for the human society, has raised global concerns on environmental sustainability, calling for high-performance materials in effective pollution treatments. Boron nitride (BN) with a structure similar to graphene possesses many extraordinary properties such as high surface areas, high oxidization resistance at high temperature, and high chemical stability. This review presents the outstanding removal percentage and environmental restoration of BN-based nanomaterials for the elimination of various pollutants from the last ten years. Notably, recent advances in the removal of organic/inorganic pollutants and interaction mechanism are outlined. BN-based materials can not only preferably remove contaminants, but also can be directly regenerated by burning in air. The BN-based materials have satisfactory sorption capacities for inorganic pollutants (e.g. heavy metal ions) and organic pollutants (e.g. dyes and pharmaceutical molecules). The interaction mechanisms between pollutants and BN-based materials are mainly surface complexation, π-π stacking, and electrostatic interactions. This paper is beneficial to further comprehend the interactions of pollutants with BN-based materials, which is also helpful for the improvement of BN-based materials and potential areas for future applications in environment remediation. [ABSTRACT FROM AUTHOR]

The biological toxicity and negative environmental effect of graphene oxide (GO) have attracted wide public concern due to its potential risks. To assess the transport behavior and to reduce the environmental hazardous of GO in natural environment, ZnO and MgO were used as coagulant for GO removal from aqueous solutions. The results indicated that GO coagulation on ZnO and MgO were scarcely affected by ionic strength. At neutral pH, the GO removal capacities could reach 232.8 mg/g on MgO and 210.8 mg/g on ZnO. The high removal capacity and short coagulation time showed the enormous advantages for the high-efficiency removal of GO from aqueous solutions, which were important for the real application of MgO and ZnO in reality. The coagulation mechanisms of GO on ZnO and MgO could be attributed to electrostatic attraction and hydrogen bond, which were further demonstrated by DFT calculations. Considering the cost, efficiency, removal capacity and reusability, one can conclude that metal oxides can be promising materials for GO efficient removal by a simple and rapid coagulation process. The findings can provide critical information about the physicochemical behavior of GO in aquatic natural environment, which is significant to decrease the environmental toxicity of GO. [ABSTRACT FROM AUTHOR]

Aniline is toxic and hard to be degraded, and thereby causes the environmental pollution seriously. Herein, a practical and green hydrothermal method was applied to fabricate terephthalic acid and pyromellitic acid intercalated layered double hydroxides (LDH) (named as TAL and PAL) for aniline efficient removal. The sorption of aniline on LDH-based materials were investigated at different experimental conditions, and the results indicated that aniline sorption on LDH, TAL and PAL were strongly dependent on pH and independent of ionic strength. The maximum sorption capacities of aniline on TAL and PAL at pH 5.0 and 293 K were 90.4 and 130.0 mg/g, respectively, which were significantly higher than that of aniline on LDH (52.6 mg/g). Based on the BET, FTIR and XPS analysis, the higher sorption capacities of TAL and PAL were mainly due to high surface area and basal spacing as well as the abundant functional groups (e.g. –COO − ). The interactions of aniline with TAL and PAL were mainly dominated by hydrogen bonds and electrostatic interactions. Such a facile synthesis method, efficient removal performance and superior reusability indicated that the aromatic acid modified LDH materials had potential application for efficient treatment of organic pollutants in environmental pollution cleanup. [ABSTRACT FROM AUTHOR]

The uncalcined glycerol-modified nanocrystallined Mg/Al layered double hydroxides (named as G-LDH) and calcined G-LDH (named as G-LDO) with molar ratio of Mg:Al = 3:1 were successfully synthesized using an easy and green hydrothermal method, and were characterized by scanning electron microscopy, transmission electron microscopy, N 2 Brunauer–Emmett–Teller surface area measurement, Fourier transformed infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). The as-synthesized G-LDH and G-LDO were applied as adsorbents to remove methyl orange (MO) from aqueous solutions at different experimental conditions, and the results showed that the interaction of MO with G-LDH and G-LDO were strongly pH-dependent and ionic strength-independent. Kinetic study indicated the MO adsorption on G-LDH and G-LDO were well simulated by pseudo-second-order model. The MO adsorption on G-LDH and G-LDO were well simulated by Langmuir model, and the maximum adsorption capacity of G-LDO (q max = 1062.3 mg/g) was much higher than that of G-LDH (q max = 443.5 mg/g) at pH = 4.5. The thermodynamic parameters calculated from temperature-dependent isotherms indicated that the adsorption was spontaneous and exothermal process. The FT-IR and XRD analysis further evidenced that the interaction of MO with G-LDH was mainly dominated by electrostatic interaction, ion exchange, hydrogen bonding and surface complexation, whereas the uptake of MO to G-LDO was mainly attributed to electrostatic interaction and surface complexation. These results suggested that the G-LDO was a promising material for the efficient removal of organic pollutants in real environmental pollution cleanup. [ABSTRACT FROM AUTHOR]

Understanding the rate and extent of 63 Ni(II) sorption and desorption on/from mineral surfaces are important to predict its mobility performance in the natural environment. We herein systematically investigated the effects of pH, electrolyte cations, humic acid (HA) and temperature on 63 Ni(II) sorption/desorption on/from Na-montmorillonite. The results indicated that the sorption/desorption of 63 Ni(II) on/from Na-montmorillonite were strongly dependent on pH and electrolyte cations. Desorption abilities of 63 Ni(II) were Na + ≈ K + > Ca 2+ ≈ Mg 2+ at the cationic concentration of 0.2 mol/L, which was associated with the clay tactoid size. The kinetic results suggested that 63 Ni(II) sorption/desorption initially increased rapidly and remained constant as time increasing. The presence of HA influenced 63 Ni(II) sorption clearly and promoted 63 Ni(II) desorption as a result of the dissolution of ternary surface complexes. Increasing temperature was favorable for the sorption reaction owing to the formation of strong inner-sphere complexes, however, hampered the desorption reaction because of the increased stability of inner-sphere complexes or the aggregation of montmorillonite. The results are crucial to understand the physicochemical behavior of radionickel in the natural environment. [ABSTRACT FROM AUTHOR]

Clay minerals have been studied extensively due to their strong sorption and complexation ability toward various environmental pollutants. In this study, the sorption of 90 Sr(II) on Na-montmorillonite was studied as a function of various environmental conditions such as pH, ionic strength, humic acid (HA) and temperature. The results indicated that the sorption of 90 Sr(II) on Na-montmorillonite was strongly dependent on pH and ionic strength. The experimental data of 90 Sr(II) sorption was simulated by the diffuse-layer model (DLM) well with the aid of Visual Minteq 3.0. At low pH, the sorption of 90 Sr(II) was dominated by outer-sphere surface complexation and ion exchange with Na + /H + on Na-montmorillonite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The presence of HA enhanced 90 Sr(II) sorption at pH < 7.0 but decreased 90 Sr(II) sorption at pH > 7.0. Langmuir and Freundlich models were used to simulate the sorption isotherms of 90 Sr(II) at three different temperatures of 303, 318 and 333 K. The thermodynamic parameters (Δ H , Δ S and Δ G ) calculated from the temperature-dependent sorption isotherms indicated that the sorption of 90 Sr(II) on Na-montmorillonite was an endothermic and spontaneous process. The thermodynamic parameters calculated from temperature-dependent sorption data were crucial to understand the interaction behavior of 90 Sr(II) with Na-montmorillonite. [ABSTRACT FROM AUTHOR]

Fe 3 O 4 nanoparticles were synthesized by hydrothermal technique and then modified with tetraethyl orthosilicate to form Fe 3 O 4 @SiO 2 nanospheres through Stöber method. The characterization results of X-ray diffraction, Fourier transformed infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and magnetic measurements evidenced the successful synthesis of Fe 3 O 4 @SiO 2 nanospheres. The as-prepared Fe 3 O 4 @SiO 2 was applied as adsorbent to remove congo red (CR) from aqueous solutions at different experimental conditions, and the results indicated that CR adsorption on Fe 3 O 4 @SiO 2 was strongly pH-dependent and weakly ionic strength-dependent at relative low pH values, indicating that the adsorption was mainly dominated by electrostatic interactions. The maximum adsorption capacities of CR on Fe 3 O 4 @SiO 2 were calculated to be 54.64 mg/g from Sips model and 50.54 mg/g from Langmuir model at T = 308 K and pH = 5.3. The thermodynamic parameters calculated from temperature-dependent isotherms indicated that the adsorption of CR on Fe 3 O 4 @SiO 2 was an spontaneous and endothermic process. The CR-adsorbed Fe 3 O 4 @SiO 2 nanospheres could be easily separated from aqueous solutions using magnetic separation technique within 40 s. These results suggested that the Fe 3 O 4 @SiO 2 nanospheres might be suitable materials for the efficient separation of dye pollutants from aqueous solutions in possible real applications. [ABSTRACT FROM AUTHOR]

The graphene oxides (GOs) have been studied extensively in multidisciplinary areas owing to their excellent physicochemical properties. The high theoretical surface areas and large amounts of oxygen-containing functional groups at the basal planes and the edge sites ensure their high sorption capacity for heavy metal ions and radionuclides from large volumes of aqueous solutions. Herein, the GOs were applied as adsorbents to remove U(VI) from aqueous solutions at different experimental conditions, and the results showed that the sorption of U(VI) on GOs was strongly dependent on pH and was not affected by ionic strength obviously. The sorption capacity of U(VI) on GOs is calculated to be 1330 mg/g at pH 4.5 and T = 20 °C, which is much higher than any other today’s materials. The interaction mechanism of U(VI) on GOs was simulated by the computational DFT calculations, and the results evidenced that the variation in pH values led to significant changes in the circumstance of functional groups on GOs. As the pH value increased, the weak physical sorption/outer-sphere surface complexation between the GOs and U(VI) at low pH turned into strong chemical sorption/inner-sphere surface complexation with the negative charged –O − or –COO − groups induced by the deprotonation of the functional groups at high pH. [ABSTRACT FROM AUTHOR]

Seawater is rich in uranium resources, but the marine environment is complicated and changeable, as well as the presence of a lot of competing ions. These are disturbing factors that cannot be ignored in seawater uranium extraction. The synthesis of adsorbents with good stability, high selectivity and large adsorption capacity has been the focus of attention. The composite adsorbent MXene-AO@LZU1 was prepared using electrostatic self-assembly of transition metal carbides and nitrides (MXenes) with structurally stable covalent organic frameworks (COF-LZU1). The results of characterizations showed that MXene-AO@LZU1 was rich in functional groups and had an effective improvement in specific surface area. MXene-AO@LZU1 exhibited an efficient performance for [UO 2 (CO 3) 3 ]4- with an adsorption saturation capacity of 88.8 mg·g−1. The adsorption amount in the simulated seawater also reached 6.8 mg·g−1. MXene-AO@LZU1 had a good selectivity for uranium and outstanding stability under various extreme conditions. In addition, XPS showed that the adsorption of uranium by MXene-AO@LZU1 relied mainly on the complexation of oxygen/nitrogen-containing functional groups with [UO 2 (CO 3) 3 ]4-. This study explored the great potential of MXenes and COFs in seawater uranium extraction, indicating that MXene-AO@LZU1 was an efficient and stable adsorbent with good development prospects. This finding was of great importance for the application of composite materials in actual environmental cleanup, and could be extended to efficiently remove other pollutants by rational ligands design. [Display omitted] • MXene-AO@LZU1 composite material was obtained by electrostatic self-assembly method. • The saturation adsorption capacity for [UO 2 (CO 3) 3 ]4- was 88.8 mg·g−1. • The adsorption amount in the simulated seawater also reached 6.8 mg·g−1. • Abundant nitrogen/oxygen functional groups promote uranium removal. • Main removal mechanism included surface complexation. [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]

• Polyurea film was coated by polyvinylidene chloride through casting method. • Water vapor transmission rate of polyurea film is greatly reduced by 74.3%. • Polyvinylidene chloride layer adhered to polyurea film is strong and durable. Polyurea (PUA) is a type of protective coating material with excellent performance. However, the water vapor barrier property of PUA is not very ideal and need to be improved. In this study, PUA film was coated by polyvinylidene chloride (PVDC) by casting of PVDC emulsion, to improve its water vapor barrier property. A polydopamine layer was introduced between the PUA and PVDC layers to provide good adhesion performance. The morphology, chemical structure and performance of the films were characterized by scanning electron microscope, fourier transform infrared spectroscopy, water contact angle analysis, and water vapor transmission rate (WVTR) tests. It is indicated that, with the thickness of the PVDC coating increasing, WVTR decreases almost linearly. When the thickness of the PVDC coating is 5.2 μm, WVTR is 12.58 g/m2·day and water vapor permeability (WVP) is 1345.65 g·µm/m2·day·kPa. The WVTR and WVP of PVDC coated PUA is greatly reduced by 74.3% and 73.9% respectively, compared to that of pure PUA film. The adhesion of the PVDC coating on the PUA surface was evaluated through the cross-cut testing method. It is shown that the adhesion is strong enough to resist the pasting and peeling by adhesive tape. [ABSTRACT FROM AUTHOR]

The effect of soluble silicate on the sorption of U(VI) to γ -Al 2 O 3 was investigated by batch experiments and extended X-ray absorption fine structure (EXAFS) method. The presence of silicate enhanced the sorption of U(VI) on γ -Al 2 O 3 surface and the sorption was attributed to inner-sphere surface complexation. The structure of the adsorbed U(VI) and silicate on γ -Al 2 O 3 was investigated in the analysis of EXAFS spectra. The fitting of the experimental EXAFS data was obtained by including two uranium coordination shells with 2 axial (O ax ) and 5 equatorial (O eq ) oxygen atoms at 1 . 79 ± 0 . 02 and 2 . 43 ± 0 . 02 Å, respectively, and the third coordination shells with Al atom at ∼3.35 Å. Silicate contributed to the formation of ternary inner-sphere surface complexes, acting as “bridge” between U(VI) and γ -Al 2 O 3 and enhanced the sorption of U(VI). The observations suggested that the interactions between U(VI) and silicate were important in controlling U(VI) retention. [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]

Based on the finite-difference time-domain (FDTD) method, a wide-band solar absorber (WA) is constructed and simulated in this paper. Due to the Fabry-Perot resonance (FPR), the near-field resonance mode, the surface plasmon resonance (SPR) and gap resonance in different structure, the WA obtains efficient and wide-band absorption. The absorption efficiency in 373–1967 nm band is >90 %, and in 817–1830 nm band is >98 %, and the average absorption efficiency at air mass 1.5 (AM 1.5) reaches 91.10 % (280–2500 nm). The structure is insensitive to the change of incident angle. The reduced absorption efficiency is 9.23 % when the incident angle increases from 0° to 60°. In addition, the structure can work stably at high temperature, and the thermal radiation efficiency at 1500 K is as high as 85.13 %. Due to the efficient and wide-band absorption and high thermal emission efficiency, the WA can be widely used in solar energy collection and energy radiation. [Display omitted] • The bandwidth of the absorption efficiency ≥ 90 % is 1594 nm, and of the absorption efficiency ≥ 98 % is 1013 nm. • The average absorption efficiency of the structure at AM 1.5 is 91.10 %. • The thermal radiation efficiency of the structure is 85.13% % at 1500 K. [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]

[Display omitted] • The characteristics of novel nanomaterials for uranium extraction are summarized. • The influencing factors for uranium extraction from seawater are introduced. • The mechanisms mainly include electrostatic, coordination, and chelation. • The opportunities and challenges in seawater uranium extraction are presented. There are abundant uranium resources in the ocean, from the perspective of resource utilization and ecological environmental protection, seawater uranium extraction is a way to regenerate uranium resources with high potential value. Due to the advantages of low cost, simple operation, practicality and environmental friendliness, the adsorption method has become one of the most commonly used and effective techniques for uranium extraction from seawater. This review first introduces commonly used adsorbents, mainly including carbon-based materials, metal organic frameworks (MOFs), covalent organic frameworks (COFs), biopolymers, amidoxime based materials and so on. Then, the main influencing factors of seawater uranium extraction by adsorption are listed, mainly including coexisting metal ions, salinity, pH, temperature and biofouling. Next, some experimental examples of the application of advanced techniques to speculate on reaction mechanisms such as coordination, chelation, electrostatic attraction, and adsorptive photocatalytic synergy are presented. Finally, this review puts forward the opportunities and challenges that still exist in seawater uranium extraction, and looks forward to its development prospects on this basis. The overview will help readers to further understand the key technologies of seawater uranium extraction and to discover more efficient and environmentally friendly materials for seawater uranium extraction, which is significant to support the development of nuclear power industry. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Dictyophora indusiate -derived biochar supported sulfide NZVI was successfully synthesized. • Sulfidation and supporting technologies could expand a new track for NZVI-based materials. • U(VI) uptake was due to the synergistic effect between adsorptive and reductive reactions. • DI-SNZVI could be a promising scavenger for U(VI) uptake form wastewater. Abstract Nanoscale zero-valent iron (NZVI) has been considered as a potential scavenger for U(VI) elimination from aqueous environment. To decrease the aggregation and to improve antioxidation, sulfidation technology and biochar were applied to modify NZVI. In this work, Dictyophora indusiate -derived biochar supported sulfide NZVI (DI-SNZVI) was synthesized and applied for U(VI) elimination. The excellent behaviors of kinetics (3 h for equilibrium), thermodynamic research and maximum removal amounts (427.9 mg·g−1 at pH = 5.0 and 298 K) revealed the outstanding performances of DI-SNZVI in U(VI) removal. The cycle experiments and different water system investigations further illustrated its potential ability for real applications. Moreover, the abundant functional groups and FeS x shell of DI-SNZVI were proved to be responsible for the enhanced removal of U(VI). In the end, the macroscopic and XPS study revealed that U(VI) elimination mechanisms were synergistic attributed to the adsorptive and reductive processes. This paper highlighted the biochar-based sulfide NZVI for efficient U(VI) elimination in environmental pollution management. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • UiO-66-AO was derived from UiO-66-CN loaded with amidoxime groups. • The sufficient functional groups endowed UiO-66-AO outstanding Eu(III) sorption capacity. • The structure of UiO-66-AO was highly stable under extremely harsh conditions. • The reaction mechanisms were electrostatic attraction and inner-sphere surface complexation. • Environmental application assessment demonstrated the practical application potential of UiO-66-AO. Abstract Extraction of Eu(III) from wastewater has recently received extensive attention in environmental water pollution improvement because Eu(III) is the chemical analogue of trivalent lanthanides [Ln(III)] and actinides [An(III)]. In this work, UiO-66-AO with remarkable physicochemical properties was designed through introducing amidoxime groups (C(NOH)NH 2) on the surface of UiO-66-CN which was derived from UiO-66-Br through introducing cyano groups (C N). SEM, TEM, BET, FT-IR, XRD, and TGA techniques demonstrated the effective synthesis and excellent structural performances of target materials. The outstanding sorption efficiency of UiO-66-AO (∼253.8 mg/g within 2 h) was verified through kinetic and thermodynamic analyses, showing that the kinetics data were well fitted by pseudo-second-order kinetic model, and the sorption isotherms were effectively fitted by Langmuir model. Based on macroscopic experiments and spectroscopic analyses (FT-IR and XPS), the removal mechanisms of Eu(III) onto UiO-66-AO were electrostatic interaction and inner-sphere surface complexation. In addition, the environmental application assessment had proved that UiO-66-AO owned excellent stability, outstanding selectivity, and remarkable Eu(III) removal percentage in simulated wastewater systems, demonstrating the great potential of UiO-66-AO to remove radionuclides from the actual wastewater. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was applied as adsorbent to efficiently eliminate the heavy metal ions from wastewater because of its large amount of functional surface groups and high surface areas. However, the contribution of different functional surface groups on the high preconcentration of heavy metal ions to GO is still unclear. Herein the GO was applied as adsorbent for the efficient preconcentration of Co(II) and the effect of functional surface groups on Co(II) removal was studied by batch sorption experiments. The results showed that the maximum sorption capacities of Co(II) on GO, NGO, MGO and NMGO were 43.6, 27.3, 23.2 and 14.6 mg/g, respectively. The elimination of Co(II) was significantly influenced by ionic strength and pH, indicated that the interaction mechanism was primarily controlled by strong surface complexation. The DFT calculation further evidenced that the oxygen-containing surface groups could form shorter bond distance with Co(II) ions than the nitrogen-containing functional groups, and the calculated adsorption energies ( E ad ) for GO–COOH–Co (44.05 kcal/mol) and GO–OH–Co (16.44 kcal/mol) were much higher than that for NGO–Co (6.33 kcal/mol). The density of states (DOS) and charge density differences of combined complexes further illustrated the strong surface complexes were formed between Co(II) and the oxygen-containing surface groups of GO surfaces. This work highlighted that the oxygen-containing surface groups played a vital role in the formation of surface complexes with Co(II) on GO, which is crucial for the preparation and application of GO in the radioactive pollution cleanup. [ABSTRACT FROM AUTHOR]

Graphical abstract Rod-like metal-organic framework (MOF-5) nanomaterial for efficient removal of U(VI) from aqueous solutions. Abstract With the widespread application of radionuclide 235U(VI), it is inevitable that part of U(VI) is released into the natural environment. The potential toxicity and irreversibility impact on the natural environment has become one of the most forefront pollution problems in nuclear energy utilization. In this work, rod-like metal-organic framework (MOF-5) nanomaterial was synthesized by a solvothermal method and applied to efficiently adsorb U(VI) from aqueous solutions. The batch experimental results showed that the sorption of U(VI) on MOF-5 was strongly dependent on pH and independent of ionic strength, indicating that the dominant interaction mechanism was inner-sphere surface complexation and electrostatic interaction. The maximum sorption capacity of U(VI) on MOF-5 was 237.0 mg/g at pH 5.0 and T = 298 K, and the sorption equilibrium reached within 5 min. The thermodynamic parameters indicated that the removal of U(VI) on MOF-5 was a spontaneous and endothermic process. Additionally, the FT-IR and XPS analyses implied that the high sorption capacity of U(VI) on MOF-5 was mainly attributed to the abundant oxygen-containing functional groups (i.e., C O and C O). Such a facile preparation method and efficient removal performance highlighted the application of MOF-5 as a candidate for rapid and efficient radionuclide contamination's elimination in practical applications. [ABSTRACT FROM AUTHOR]

Hydrangea-like carbon sphere@layered double hydroxide (CS@LDH) nanocomposite was fabricated by one-step hydrothermal synthesis strategy using carbon sphere and Ni-Al LDH as monomer molecules. The CS@LDH nanocomposites were then applied as adsorbents to eliminate U(VI) from aqueous solutions and showed excellent elimination performance to U(VI) from aqueous solutions because of its strong synergistic effects between metal-oxygen functional groups (Ni-O and Al-O) and free-metal functional groups (C O, C O C, and O C O). The removal of U(VI) on CS@LDH was mainly dominated by inner-sphere surface complexation, which was confirmed with batch sorption experiments, FTIR and XPS analysis. Furthermore, the maximum sorption capacity of U(VI) on CS@LDH (0.6 mmol/g) was 2.0 times higher than that of U(VI) on Ni-Al LDH (0.3 mmol/g) and approximately 1.5 times higher than that of U(VI) on CS (0.4 mmol/g) at pH = 5.0 and T  = 298 K. The thermodynamic parameters suggested that the sorption of U(VI) was a typical spontaneous and endothermic process. The sorption isotherms were well simulated by Langmuir model, suggesting that the sorption was monolayer coverage. The CS@LDH can be used as superior adsorbent for efficient elimination of radionuclides in environmental pollution remediation. This study also demonstrated a new strategy to improve the physicochemical properties of other low efficiency adsorbents through polymerization reaction. [ABSTRACT FROM AUTHOR]

The nanoscaled zero-valent iron (nZVI) supported zeolite MCM-41 composites (nZVI/MCM) were synthesized, and applied for the immobilization of Cr(VI) from aqueous solutions. The precise role of MCM-41 and nZVI in the immobilization and reduction of Cr(VI) was characterized using SEM, TEM, HRTEM, HRTEM-EDS, XPS and EXAFS techniques. Comparing to the bare nZVI nanoparticles, the as-synthesized nZVI/MCM composites showed higher efficiency on Cr(VI) immobilization due to the high synergistic effect of Cr(VI) reduction by nZVI and sorption by MCM-41. The morphology and visualizing analysis indicated that nZVI was uniformly distributed on the surfaces of MCM-41, which reduced the aggregation of nZVI apparently and thereby increased the reduction activity. XPS and EXAFS analysis showed that nZVI could promote Cr(VI) reduction into Cr(III), and the sorption and reduction reactions were occurred on bare nZVI. MCM-41 acted as a scavenger for the insoluble products, which could improve the reduction activity of nZVI. The high performance of nZVI/MCM composites showed the promising strategy for the efficient decontamination of Cr(VI) pollution in environmental pollution cleanup. [ABSTRACT FROM AUTHOR]

Uranium has attracted sustained attention due to its high mobility and biotoxicity. Among various techniques, sorption is considered as the most effective technique to treat the U(VI)-containing wastewater. In serving for low-cost adsorbents, layered double hydroxides (LDHs) have been proved to be promising candidates. However, the interaction mechanism of U(VI) with LDHs is still unclear, although plenty of LDHs have been used in this field. Herein, we developed two novel methods to fabricate ternary LDHs (MgFeAl LDHs and NiFeAl LDHs) and applied the ternary LDHs as adsorbents to investigate their sorption performance towards U(VI). The results showed that the sorption was endothermic and followed the pseudo-second-order kinetics through the formation of inner-sphere surface complexes, and the sorption isotherms were simulated by the Langmuir model well. Furthermore, systematic spectroscopy characterization indicated that the sorption occurred on the surface sites of Mg-OH and Ni 2+ –OH, while the CO 3 2− in the gallery space also played an important role. This work highlighted the synthesis of high-efficient materials and their application in wastewater treatment. [ABSTRACT FROM AUTHOR]

Herein, a practical and simple calcination method was used to synthesize layered double oxides (denoted as LDO) and layered double oxides/carbon dots nanocomposites (denoted as LDO-C) for U(VI) efficient removal. The U(VI) adsorption on LDO and LDO-C were investigated under various experimental conditions, and the results indicated that U(VI) uptake on LDO and LDO-C were consumingly dependent on pH and ionic strength at pH > 6, and independent of ionic strength at pH < 6. The adsorption processes of U(VI) on LDO and LDO-C were spontaneous and endothermic, and well simulated by pseudo-second-order model. The maximum adsorption capacity of U(VI) on LDO-C was calculated to be 354.2 mg/g at pH = 5.0 and T = 298 K, which was significantly higher than that of U(VI) on LDO (237.6 mg/g). Particularly, BET, F T-IR, XPS and EXAFS analysis suggested that the higher adsorption capacity of LDO-C was mainly attributed to higher specific surface area and more abundant surface oxygen-containing functional groups (e.g. C-OH), and the main interaction mechanisms were surface complexation and electrostatic interactions. In addition, LDO-C also showed higher adsorption capacity of 241 Am(III) than LDO. All in all, the efficient removal performance and superior versatility of LDO-C indicated that it could be applied as promising candidate for efficient immobilization of radioactive pollutant in environmental pollution management. [ABSTRACT FROM AUTHOR]

Graphical abstract A novel arginine modified hydroxyapatite carbon microsphere (C@HAp/Arg) composite were synthesized by a facile and green method and exhibited superior adsorption efficiency for removal of U(VI). Abstract Uranium was not only the main source of nuclear energy but also one of the long-lived radionuclide. Herein, a novel arginine modified hydroxyapatite carbon microsphere composites (defined as C@HAp/Arg) obtained promptly via a one-step mild hydrothermal method, was applied to remove U(VI) from aqueous solutions. Based on the characterization of transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), the synthesized C@HAp/Arg presented globular morphology and abundant functional groups (e.g., COO−), which were beneficial to its combination with U(VI). The interaction mechanism and removal capability of U(VI) on C@HAp/Arg were studied by batch adsorption technique and spectroscopy analysis. The results implied that U(VI) can form strong surface complexes on C@HAp/Arg. The kinetics adsorption of U(VI) followed pseudo-second-order kinetic model with high removal efficiency (∼95% within 5 h at pH 5.0). The adsorption isotherms were well fitted by Langmuir model, implying that U(VI) uptake on C@HAp/Arg was monolayer coverage. It was found that the maximum adsorption capacities of CSs, C@HAp and C@HAp/Arg toward U(VI) were calculated to be 23.16, 72.09 and 569.66 mg/g, respectively, at 298.15 K and pH 5.0, and thermodynamic parameters revealed that the adsorption processes of U(VI) were spontaneous and endothermic. In addition, effect of co-existed ions and CO 3 2− concentrations demonstrated that U(VI) adsorption on C@HAp/Arg was weakly interfered by foreign ions and carbonate concentrations. More importantly, the adsorption performance of U(VI) on C@HAp/Arg was still over ∼87% after five cycles. Therefore, it was noted that the versatile C@HAp/Arg could be potentially used as a powerful building block for the enrichment and disposal of U(VI) from aqueous solutions, which could efficiently reduce the potential toxicity of U(VI) in the U(VI)-contaminated water. [ABSTRACT FROM AUTHOR]

A novel low-cost, effective and environmental-friendly laminated carbon nitride decorated with polydopamine (PDA) and grafted with polyethyleneimine (PEI) brush ( l -C 3 N 4 /PDA/PEI 3 ) was successfully synthesized and applied as environmental cleaner for removing U(VI) ions from aqueous solutions under various environmental conditions. The adsorption isotherms fitted well by the Langmuir model, suggesting that the removal of U(VI) on l -C 3 N 4 /PDA/PEI 3 was monolayer coverage. The effects of different PEI contents were also investigated and the results demonstrated that the adsorption capacity of U(VI) on l -C 3 N 4 /PDA/PEI x decreased at higher content of PEI. Typically, various cations (Ca 2+ and Mg 2+ ) and SO 4 2− could inhibit the adsorption through competitive coordination with U(VI), while CO 3 2− promoted U(VI) sorption owing to the formation of indissolvable complexes. The main driving force between U(VI) and l -C 3 N 4 /PDA/PEI 3 was surface complexation with various functional groups (C C, C O, N C C, and C C or C H) and electrostatic attraction. According to the analysis of EXAFS spectra, the occurrence of U-C and U-U shell revealed that inner-sphere complexation and surface co-precipitation dominated the adsorption of U(VI) on l -C 3 N 4 /PDA/PEI 3 at pH 5.0. The composites were also applied to remove 243 Am(III), Cu(II) and Pb(II) ions at different pH values, and similar results were also found for these metal ions. Such a facile synthesis method and efficient removal performance suggested that the l -C 3 N 4 /PDA/PEI 3 materials might be a promising adsorbent for efficient elimination of radionuclides and heavy metal ions in environmental pollution management. [ABSTRACT FROM AUTHOR]

Hierarchical silicon dioxide-@-layered double hydroxide (SiO 2 @LDH) nanocomposites were synthesized by a facile in situ co-precipitation method, and characterized by XRD, FESEM, FT-IR and XPS in detail. The sorption of uranium (U(VI)) and methyl orange (MO) on SiO 2 @LDH were investigated as a function of pH, ionic strength, contact time and temperature. The results indicated that the sorption of U(VI) and MO were strongly dependent on pH, and weakly dependent on ionic strength, demonstrating that the interaction of U(VI) was mainly dominated by inner-sphere surface complexation and the sorption of MO was mainly attributed to electrostatic attraction due to the high removal efficiency (∼98% within 4 h for U(VI) ions, and ∼92% within 10 min for MO). The kinetics sorption of U(VI) and MO both followed the pseudo-second-order model well, suggesting that the sorption processes were chemical sorption. The sorption isotherms of U(VI) and MO on SiO 2 @LDH were well fitted by the Langmuir model, and the maximum sorption capacities of SiO 2 @LDH were calculated to be 303.1 mg·g −1 for U(VI) and 166.1 mg·g −1 for MO. The thermodynamic parameters revealed that the sorption of U(VI) and MO was spontaneous process. Integrating the experimental result analysis, the hierarchical SiO 2 @LDH may be a promising material for the efficient elimination of radionuclides and dyes from aqueous solutions in natural environmental pollution cleanup. [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]

[Display omitted] • TC-AO were used to adsorb U(VI) and Eu(III). • Abundant functional groups and good selectivity endowed TC-AO excellent property. • The practical application potential of TC-AO was confirmed. • The mechanisms were surface complexation and electrostatic interaction. Although two-dimensional transition metal carbides and carbonitrides (MXenes) are becoming increasingly popular in contaminant remediation field, the preparation of MXene nanosheets that can efficiently eliminate the target pollutants still deserves in-depth investigation. Here we produced amidoxime Ti 3 C 2 T x nanosheets (TC-AO), which were efficient radionuclide adsorbents with high stability and positive affinity, by introducing the amidoxime group into the Ti 3 C 2 T x MXene surface through grafting by diazonium salt. The high stability and abundant functional groups of TC-AO were demonstrated by different characterization techniques such as scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA), and X-ray photoelectron spectroscopy (XPS). Multiple factors affecting the radionuclide removal performance were explored, including reaction time, temperature, pH, ionic strength, anions and cations. The experimental results demonstrated that the radionuclide uptake by TC-AO was a heat-absorbing, spontaneous single-molecule chemisorption process and was consistent with the pseudo-secondary and Langmuir models. When pH < 6, the mechanism of uranium removal was inner complexation, and as the pH continued to increase, uranium removal shifted to outer complexation. Furthermore, the results certificated that TC-AO exhibited fast reaction kinetics (reaching equilibrium in about 20 min), excellent removal efficiency (279.57 mg U·g−1 and 73.99 mg Eu·g−1), outstanding selectivity and good stability. The studies showed that TC-AO had good stability and functionality, which was not only valuable for the design of MXene based adsorbents, but also provided a meaningful option for the extraction of radioactive pollutants from wastewater. [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]

[Display omitted] • SNZVI was synthesized and exhibited excellent affinity towards DCP. • Surface sulfidation enhanced the physicochemical properties of pristine NZVI. • The efficiencies of DCP by degradation were much higher than adsorptive processes. • Fenton-like reaction and generated ROS dominated the degradation processes of DCP. Surface sulfidation has become a desirable technique to enhance the physicochemical properties of nanoscale zero-valent iron (NZVI) and improve the decontamination efficiency for organic pollutants. However, the macroscopic elimination performance and microscopic reaction mechanism of sulfide NZVI (SNZVI) towards organic matters remains uncovered. Herein, we fabricated SNZVI via one-step dithionite-method and applied it for heterogeneous Fenton-like elimination of 2,4-Dichlorophenol (DCP). The sulfidation technique greatly improved the stability, specific area, oxidized resistance, hydrophobicity, and functionality. The efficiency of degradation (86.3%) was approximately 7 times higher than adsorption (12.6%) under N 2 condition, indicating the promising potential of SNZVI in environmental governance. Moreover, Fenton-like reaction and reactive oxygen species (ROS) were confirmed to dominate the degradation process, and the generated radicals had priority to degrade DCP rather than corroded SNZVI. Furthermore, the result of gas chromatography-mass spectrometry (GC–MS) confirmed that DCP was mainly decomposed into harmless alkanes and inorganic matters, which significantly reduced the perniciousness of DCP. Overall, this research bridged the knowledge gap between organic pollutant removal and the advanced oxidation reaction of NZVI-based materials after surface sulfidation. [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]

• The synthesis strategies of ZIFs are briefly introduced and summarized. • Batch experiment, spectral analysis and DFT are used to explore mechanisms. • The mechanisms mainly ascribe to coordination and electrostatic interaction. • Large SSA and sufficient functional groups endow ZIFs excellent performance. • Multi-factor influences demonstrate the practical application potential of ZIFs. With the rapid economic globalization and energy development, heavy metal ions/radionuclides are inevitably discharged into aqueous system and cause pollution, which seriously endanger human health and environmental sustainability. In recent years, zeolitic imidazolate frameworks (ZIFs) with huge specific surface area, excellent pore structure and abundant surface functional groups show great potential in the elimination of heavy metal ions/radionuclides. This review systematically summarizes the research progress of ZIFs and ZIF-based materials for capturing heavy metal ions/radionuclides. Firstly, the preparation and modification of ZIF-based materials are briefly introduced. Then, the removal behaviors and possible interaction mechanisms between ZIF-based materials and pollutants are explored through macro-batch experiments, micro-spectroscopy analyses and theoretical calculations. In addition, the partition coefficient as evaluation indicator was employed to objectively compare the removal performance of ZIFs and other commonly used traditional adsorbents for heavy metal ions/radionuclides. Finally, the challenges and prospects of ZIF materials in environmental governance are briefly discussed so as to provide references for future research and practical applications. [ABSTRACT FROM AUTHOR]

Highly porous zeolitic imidazolate frameworks (ZIFs), with disparate metal ions (ZIF-8 and ZIF-67), disparate organic ligands (ZIF-9 and ZIF-67), single or double central metal atoms (ZIF-8, Zn/Co-ZIF and ZIF-67) were prepared and used in the elimination of typical radionuclide U(VI). The detailed interaction mechanisms were studied by batch experiments, spectral analyses and DFT calculation. Langmuir isotherms model revealed a decreasing tendency to remove U(VI): ZIF-8 (540.4 mg/g) > Zn/Co-ZIF (527.5 mg/g) > ZIF-9 (448.6 mg/g) > ZIF-67 (368.2 mg/g). Based on the effects of pH and foreign ions, FTIR and XPS spectra analyses, the possible interaction mechanisms of U(VI) onto ZIFs were surface complexation and electrostatic interaction. Among them, ZIF-8 with Zn metal center and 2-methylimidazolate organic ligand had the best elimination capacity for U(VI) because of its large surface area, active metal ion and abundant nitrogen-containing groups (e.g., C–N, Zn–N and C N). Specially, the adsorption energy of ZIF-8-Zn2-UO 2 2+ structure was −2.299 eV obtained by DFT calculation, illustrating that U(VI) and N atoms were formed the most stable bidentate coordination compounds. This paper highlights the effects of the hydroxylated metals, the functional groups of the imidazole ring on the elimination of U(VI), which can provide constructive suggestions for further adsorbent materials amelioration. Image 1 • ZIF-8, ZIF-9, ZIF-67 and Zn/Co-ZIF were fabricated by stirring at room temperature. • Excellent structural performances endowed four ZIFs outstanding sorption capacity. • The differences in adsorption mechanism of four ZIFs were investigated in detail. • The N atoms of ZIF-8 formed bidentate coordination compounds with U(VI). [ABSTRACT FROM AUTHOR]

• Water stable Fe 3 O 4 @ZIF-8 was fabricated through a facile modification strategy. • Excellent structural performances endowed Fe 3 O 4 @ZIF-8 outstanding absorbability. • Multi-factors influence demonstrated the practical application potential. • The mechanisms were electrostatic attraction and inner-sphere surface complexation. • The excellent uptake capabilities made Fe 3 O 4 @ZIF-8 a promising adsorbent. The water stable core-shell microspheres (Fe 3 O 4 @ZIF-8) with strong magnetism were successfully fabricated through a facile modification strategy. Concrete procedures included firstly pretreatment of Fe 3 O 4 core with anionic polyelectrolyte to acquire negatively charged Fe 3 O 4 particle surface, followed by nucleation through attracting Zn2+ cation, and then growth of a thin layer of ZIF-8 (~25 nm). Various characterization techniques (SEM, TEM, FT-IR, XRD, VSM, BET and XPS) indicated that the Fe 3 O 4 @ZIF-8 microspheres were highly stable and magnetic with a large specific surface area (606.91 m2/g) and fairly sufficient functional groups (NH , OH, COOH, Zn O, N O and C N). Multi-factors affecting the radionuclides removal performance on Fe 3 O 4 @ZIF-8 was adequately explored, comprising contact time, temperature, pH, ionic strength, co-existing ions and extreme conditions. And the results showed that Fe 3 O 4 @ZIF-8 exhibited fast reaction kinetics (~30 min to achieve equilibrium), excellent uptake capabilities (539.7 mg U/g and 255.6 mg Eu/g), remarkable selectivity and favorable physicochemical stability. These researches suggested that Fe 3 O 4 @ZIF-8 could not only simultaneously achieve favorable stability and functionality, but also easily to be separated by external magnetic field after used in radioactive sewage treatment, which was of considerable practical utility in extracting radioactive wastes though in harsh circumstance. [ABSTRACT FROM AUTHOR]