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Airbus UpNext has launched an Advanced Superconducting and Cryogenic Experimental powertraiN Demonstrator (ASCEND) project in 2021 to develop a superconducting electric aircraft propulsion system. The demonstrator system power is rated at 500 kW with the dc voltage of 300 V. A dc networks can achieve smaller footprint and improved distribution efficiency. However, fault management in dc networks is much more challenging than ac systems because: firstly, there is no natural zero-crossing of the current to isolate the fault; and secondly, the rate of rise of fault currents is often significantly higher due to lower system impedances. Resistive superconducting fault current limiter (RSFCL) is a passive device that provides protection without requiring external input, making it inherently reliable. Non-inductive bifilar pancake RSFCL coils supported by G10 former are designed and built based on ASCEND system specification. This paper will present the design of RSFCL using 2G high temperature superconductor tapes for ASCEND demonstrator. A dc fault current testing circuit is built for testing of RSFCL. RSFCL is experimentally tested from 65 K to 77 K in the sub-cooled liquid nitrogen cryostat. The current limitation and recovery time are compared for different operating temperatures. In conclusion, RSFCL using HTS tapes demonstrates effective and fast current limitation within 1ms, which significantly improves the reliability of the system.

Large-scale electric aircraft are a promising technology that could revolutionise air travel to reduce the environmental impact. Fault current limitation and interruption technology is crucial to realise the safety and reliability of the electric aircraft, in particular for large-scale electric aircraft using a DC distribution network. This article proposes to integrate a resistive superconducting fault current limiter (SFCL) with a cryogenic DC solid-state circuit breaker (SSCB) so that the SFCL limits the fault current to acceptable levels in DC networks allowing the SSCB to operate quickly and reliably. A sub-cooled liquid nitrogen cryostat, which can be controlled from 65 K to 77 K, is designed and built for the integration of SFCL and DC SSCB. An SFCL and SSCB prototype is designed and experimentally tested at cryogenic temperatures, which successfully demonstrates the ability to limit and interrupt currents at cryogenic environment.

Mercury (Hg) contamination in groundwater poses significant environmental and health risks, necessitating effective remediation strategies. Recently, molybdenum disulfide (MoS2) nanosheets have emerged as a promising nanomaterial for the remediation of Hg-associated contaminated groundwater. However, the complex interactions between ubiquitous natural organic matter (NOM) and MoS2may play a significant role in controlling the removal of Hg from groundwater. In this study, we investigated the mechanisms underlying the role of NOM in Hg(ii) removal by MoS2. Our findings demonstrated that NOM inhibited the Hg(ii) removal by MoS2from groundwater at a high molar ratio of Hg/MoS2. However, at a low molar ratio of Hg/MoS2, NOM hardly affected the removal performance of MoS2on Hg(ii) because NOM was unable to compete with sufficient MoS2to complex with Hg(ii). The inhibitory effect of NOM on Hg(ii) removal was found to be determined by both the molecular weight (MW) and functional groups of NOM: the NOM fraction with higher MW exhibited a higher degree of inhibition, and the –SH groups displayed preferential binding of Hg(ii) rather than the –COOH group. It was concluded that the reduction of MoS2to Hg(ii) gradually decreased with increasing addition of NOM, attributed to NOM complexation with Hg(ii). Overall, this study provides insights into the significance of NOM characteristics in controlling the removal of Hg(ii) from groundwater.

The economic value of recovering gold from electronic waste (e-waste) has generated significant interest, but selective capture of gold from complex acidic electronic leaching solutions remains challenging. Here, we synthesized poly-m-phenylenediamine (PmPD) nanoparticles with a positively charged surface and amino functional groups, resulting in an adsorption capacity of 2063 mg/g for Au(III) in acidic solutions, superior to most traditional adsorbents. Electrostatic adsorption and reduction were identified as the adsorption mechanism for Au(III) by zeta potential, X-ray diffraction, transmission electron microscope, Fourier transform infrared, and X-ray photoelectron spectroscopy analyses. To enable adsorbent recycling, PmPD nanoparticles were assembled into adsorptive membranes and used for gold recovery from e-wastewater via a continuous-flow membrane separation process. The PmPD membrane achieved a dynamic gold recovery capacity of approximately 530 mg/g and could be effectively regenerated after washing with a mixture of thiourea and HCl. We demonstrated the practical application of the adsorptive membranes by recovering about 100% of gold from the leaching solution of waste printed circuit boards of computers. Finally, the recovered gold nanoparticles on the PmPD membrane were used to catalyze the degradation of p-nitrophenol, showcasing the catalytic property of gold. The Au@PmPD membrane loaded with 4 mg gold exhibited a high catalytic reduction performance with an apparent rate constant of 0.59 min–1, one of the highest catalytic degradation rate constants of p-nitrophenol reported to date. Our study presents an effective and economical approach for recovering gold from e-waste, providing a prototype of resource recovery and reuse.

Cerium oxide (CeO2) nanoparticles are one of the most important engineered nanomaterials with demonstrated applications in industry. Although numerous studies have reported the plant uptake of CeO2, its fate and transformation pathways and mechanisms in plant-related conditions are still not well understood. This study investigated the stability of CeO2in the presence of organic ligands (maleic and citric acid) and light irradiation. For the first time, we found that organic ligands and visible light had a synergistic effect on the reductive dissolution of CeO2with up to 30% Ce releases after 3 days, which is the highest release reported so far under environmental conditions. Moreover, the photoinduced dissolution of CeO2in the presence of citrate was much higher than that in maleate, which are adsorbed on the surface of CeO2through inner-sphere and outer-sphere complexation, respectively. A novel ligand-dependent photodissolution mechanism was proposed and highlighted: upon electron–hole separation under light irradiation, the inner-sphere complexed citrate is more capable of consuming the hole, prolonging the life of electrons for the reduction of Ce(IV) to Ce(III). Finally, reoxidation of Ce(III) by oxygen was observed and discussed. This comprehensive work advances our knowledge of the fate and transformation of CeO2in plant surroundings.

The aggregation–redispersion behavior of nanomaterials determines their transport, transformation, and toxicity, which could be largely influenced by the ubiquitous natural organic matter (NOM). Nonetheless, the interaction mechanisms of two-dimensional (2D) MoS2and NOM and the subsequent influences on the redispersion behavior are not well understood. Herein, we investigated the redispersion of single-layer MoS2(SL-MoS2) nanosheets as influenced by Suwannee River NOM (SRNOM). It was found that SRNOM played a decisive role on the redispersion of MoS22D nanosheets that varied distinctly from the 3D nanoparticles. Compared to the poor redispersion of MoS2aggregates in the absence or post-addition of SRNOM to the aggregates, co-occurrence of SRNOM in the dispersion could largely enhance the redispersion and mobility of MoS2by intercalating into the nanosheets. Upon adsorption to SL-MoS2, SRNOM enhanced the hydration force and weakened the van der Waals forces between nanosheets, leading to the redispersion of the aggregates. The SRNOM fractions with higher molecular mass imparted better dispersity due to the preferable sorption of the large molecules onto SL-MoS2surfaces. This comprehensive study advances current understanding on the transport and fate of nanomaterials in the water system and provides fresh insights into the interaction mechanisms between NOM and 2D nanomaterials.

The hot deformation behavior of 18CrNiMo7-6 steel at temperatures of 900 ~ 1150 °C and strain rate of 0.01 ~ 5 s−1was studied by isothermal single-pass compression experiment. The critical recrystallization model was used to determine the relationship between the critical stress and the peak stress as σc/σp=0.89. Meanwhile, the dynamic recrystallization mechanism of the samples at different deformation stages was analyzed by electron backscatter diffraction (EBSD) and metallographic microscope. The microstructure evolution shows the following: when the strain is 0.05, the work hardening is the main mechanism, and the lattice distortion near the grain boundary leads to the accumulation of dislocations, which provides the impetus for the recrystallization nucleation at the grain boundary; when the strain is 0.2, the dynamic recrystallization mechanism crystal has just started, and the small-sized recrystallized grains are formed at the grain boundary; in the meantime, dislocation rearrangement occurs in the coarse grain.When the strain is 0.5, the dynamic recrystallization consumes a large number of low-angle grain boundaries into high-angle grain boundaries by means of subgrain rotation and finally forms fine recrystallized grains in the coarse grains. This process will continue until the end of recrystallization, and the dislocations in the material matrix will tend to homogenize.

The demand for highly permeable and selective thin-film composite (TFC) nanofiltration membranes, which are essential for seawater and brackish water softening and resource recovery, is growing rapidly. However, improving and tuning membrane permeability and selectivity simultaneously remain highly challenging owing to the lack of thickness control in polyamide films. In this study, we fabricated a high-performance interlayered TFC membrane through classical interfacial polymerization on a MoS2-coated polyethersulfone substrate. Due to the enhanced confinement effect on the interface degassing and the improved adsorption of the amine monomer by the MoS2interlayer, the MoS2-interlayered TFC membrane exhibited enhanced roughness and crosslinking. Compared to the control TFC membrane, MoS2-interlayered TFC membranes have a thinner polyamide layer, with thickness ranging from 60 to 85 nm, which can be tuned by altering the MoS2interlayer thickness. A multilayer permeation model was developed to delineate and analyze the transport resistance and permeability of the MoS2interlayer and polyamide film through the regression of experimental data. The optimized MoS2-interlayered TFC membrane (0.3-inter) had a 96.8% Na2SO4rejection combined with an excellent permeability of 15.9 L m–2h–1bar–1(LMH/bar), approximately 2.4 times that of the control membrane (6.6 LMH/bar). This research provides a feasible strategy for the rational design of tunable, high-performance NF membranes for environmental applications.

ABSTRACTThe magnetically driven fluid flow and solidification process in a curved round bloom continuous caster for production of a highstrength low-alloy steel grade (Q345) with the diameter of ø600mm by a combined rotary electromagnetic stirring including the mold, the strand and the final electromagnetic stirring (M+S+F-EMS) is numerically described. The strand surface temperature and the solidified shell thickness are compared and validated by the available measured data. The magnetic field, fluid flow, temperature field and macrosolidification behaviors under the combined electromagnetic stirring are analyzed. The effects of casting speed and the position of the FEMS on the solidification and electromagnetic stirring are focused. Results show that the variation of casting speed is very important to control the length of liquid core and the solidification pool thickness for a large-size round bloom. The pool thickness and liquid fraction of the melt determines the range of the optimum stirring location and the effectiveness of the final electromagnetic stirring.

The magnetically driven fluid flow and solidification process in a curved round bloom continuous caster for production of a highstrength low-alloy steel grade (Q345) with the diameter of ø600mm by a combined rotary electromagnetic stirring including the mold, the strand and the final electromagnetic stirring (M+S+F-EMS) is numerically described. The strand surface temperature and the solidified shell thickness are compared and validated by the available measured data. The magnetic field, fluid flow, temperature field and macrosolidification behaviors under the combined electromagnetic stirring are analyzed. The effects of casting speed and the position of the FEMS on the solidification and electromagnetic stirring are focused. Results show that the variation of casting speed is very important to control the length of liquid core and the solidification pool thickness for a large-size round bloom. The pool thickness and liquid fraction of the melt determines the range of the optimum stirring location and the effectiveness of the final electromagnetic stirring.

Aggregation significantly influences the transport, transformation and bioavailability of engineered nanomaterials in aquatic environments. As one of the most well-studied two-dimensional transition metal dichalcogenide nanomaterials, the colloidal stability of molybdenum disulfide (MoS2) has been reported under different environmental conditions. Nonetheless, the intrinsic aggregation behavior of this material as influenced by its physicochemical properties is not well understood. This study investigated the correlation of the phase composition and geometric structure of MoS2with the aggregation behavior, aggregate stability and transport behavior of the nanomaterials. The results revealed that soft Lewis acid Pb2+exhibits higher destabilization for metallic 1T MoS2, whereas the semiconducting 2H phase has a higher tendency to aggregate in the presence of hard Lewis acid Ca2+. The different colloidal stabilities in response to cations could be well explained by the inner-sphere complexation of Pb2+and outer-sphere interaction of Ca2+with the surface of MoS2, respectively. With respect to the influences of geometric structure on the colloidal stability, the suspension of flower-like MoS23D nanoparticles is more stable compared to its 2D nanosheet counterpart, as reflected by the higher critical coagulation concentrations of cations and lower aggregation rate at the same MoS2mass concentration. Finally, redispersion and column experiments were conducted to evaluate the stabilities and remigration behavior of MoS2aggregates. Deposition of MoS2nanomaterials occurred in the presence of cations and the aggregates of MoS23D nanoparticles were shown to be unstable and susceptible to redispersion/remigration due to the loose aggregate structure. This study comprehensively evaluated the intrinsic aggregation behaviors of engineered MoS2nanomaterials with important implications for environmental fate and risk.

Aggregation significantly influences the transport, transformation, and bioavailability of engineered nanomaterials. Two–dimensional MoS2nanosheets are one of the most well-studied transition-metal dichalcogenide nanomaterials. Nonetheless, the aggregation behavior of this material under environmental conditions is not well understood. Here, we investigated the aggregation of single-layer MoS2(SL-MoS2) nanosheets under a variety of conditions. Trends in the aggregation of SL-MoS2are consistent with classical Derjaguin–Landau–Verwey–Overbeek (DLVO) colloidal theory, and the critical coagulation concentrations of cations follow the order of trivalent (Cr3+) < divalent (Ca2+, Mg2+, Cd2+) < monovalent cations (Na+, K+). Notably, Pb2+and Ag+destabilize MoS2nanosheet suspensions much more strongly than do their divalent and monovalent counterparts. This effect is attributable to Lewis soft acid–base interactions of cations with MoS2. Visible light irradiation synergistically promotes the aggregation of SL-MoS2nanosheets in the presence of cations, which was evident even in the presence of natural organic matter. The light-accelerated aggregation was ascribed to dipole–dipole interactions due to transient surface plasmon oscillation of electrons in the metallic 1T phase, which decrease the aggregation energy barrier. These results reveal the phase-dependent aggregation behaviors of engineered MoS2nanosheets with important implications for environmental fate and risk.

Defect engineering of metal organic frameworks offers potential prospects for tuning their features toward particular applications. Herein, two series of defective UiO-66 frameworks were synthesized via changing the concentration of the linker and synthetic temperature of the reaction. These defective materials showed a significant improvement in the capability of Pb(II) removal from wastewater. This strategy for defect engineering not only created additional active sites, more open framework, and enhanced porosity but also exposed more oxygen groups, which served as the adsorption sites to improve Pb(II) adsorption. A relationship among degree of defects, texture features, and performances for Pb(II) removal was successfully developed as a proof-of-concept, highlighting the importance of defect engineering in heavy metal remediation. To investigate the kinetic and adsorption isotherms, we performed adsorption experiments influenced by the time and concentration of the adsorbate, respectively. For the practicality of the materials, the most significant parameters such as pH, temperature, adsorbent concentration, selectivity, and recyclability as well as simulated natural surface water were also examined. This study provides a clue for the researchers to design other advanced defective materials for the enhancement of adsorption performance by tuning the defect engineering.

Point-of-use (POU) devices with satisfactory lead (Pb2+) removal performance are urgently needed in response to recent outbreaks of lead contamination in drinking water. This study experimentally demonstrated the excellent lead removal capability of two-dimensional (2D) MoS2nanosheets in aqueous form and as part of a layer-stacked membrane. Among all materials ever reported in the literature, MoS2nanosheets exhibit the highest adsorption capacity (740 mg/g), and the strongest selectivity/affinity toward Pb2+with a distribution coefficient Kdthat is orders of magnitude higher than that of other lead adsorption materials (5.2 × 107mL/g). Density functional theory (DFT) simulation was performed to complement experimental measurements and to help understand the adsorption mechanisms. The results confirmed that the cation selectivity of MoS2follows the order Pb2+> Cu2+≫ Cd2+> Zn2+, Ni2+> Mg2+, K+, Ca2+. The membrane formed with layer-stacked MoS2nanosheets exhibited a high water flux (145 L/m2/h/bar), while effectively decreasing Pb2+concentration in drinking water from a few mg/L to less than 10 μg/L. The removal capacity of the MoS2membrane is a few orders of magnitude higher than that of other literature-reported membrane filters. Therefore, the layer-stacked MoS2membrane has great potential for POU removal of lead from drinking water.

Core–shell structure of SiO2@MgAl-layered double hydroxide (SiO2@LDH) as a novel filler was prepared and incorporated into solution-polymerized styrene butadiene rubber/butadiene rubber (SSBR/BR) matrix to prepare SiO2@LDH–SSBR/BR composites. The results revealed the advanced structure of SiO2@LDH in the application of elastomer and the strongly interaction between SiO2and LDH. The investigation of the fracture surface scanning and the study of ‘Payne effect’ to the SSBR/BR compounds indicated a good dispersity of filler in the rubber matrix. In addition, the SiO2@LDH–SSBR/BR composites showed an increased modulus (300% strain) and a decreased modulus (100% strain) compared with commercialized Zeosil 1165MP highly-dispersed SiO2nanoparticles. The synergistic enhancement of SiO2and LDH in rubber matrix was discussed. The remarkable comprehensive properties enhancement of all the SiO2@LDH–SSBR/BR was obviously observed in the dynamic mechanical analysis compared with the SiO2–SSBR/BR samples. The results in this study strongly illustrate that SiO2@LDH nanocomposites could be a good candidate as a kind of reinforcement filler for the green tires.

Recent studies have demonstrated that the significant benefit can be achieved by using mobile sinks for data gathering in wireless sensor networks (WSNs). However, most of them employed a typical scheme that the mobile collector pauses at the anchor points on its moving tour for a period time to collect the data from nearby sensors. In this paper, the data gathering process is divided into two stages named parking communication (PC) and moving communication (MC). We focus on maximising the total amount of data gathering by the mobile sink, and formulate the problem as two different optimisation models under several constraints for these two different communication stages. Accordingly, dual decomposition and simplex methods are dexterously exploited to derive the optimal communication time and flow rates allocation schemes. Computational results demonstrate the efficiency of the proposed algorithms.

We investigated the removal of heavy metals from water by two-dimensional MoS2nanosheets suspended in aqueous solution, and restacked as thin film membranes, respectively. From these studies we elucidated a new heavy metal ion removal mechanism that involves a reduction–oxidation (redox) reaction between heavy metal ions and MoS2nanosheets. Ag+was used as a model species and MoS2nanosheets were prepared via chemical exfoliation of bulk powder. We found that the Ag+removal capacity of suspended MoS2nanosheets was as high as ∼4000 mg/g and adsorption accounted for less than 20% of removal, suggesting the reduction of Ag+to metallic silver as a dominant removal mechanism. Furthermore, we demonstrated that MoS2membranes were able to retain a similar high removal capacity, and attribute this capability to the formation of a conductive, permeable multilayer MoS2structure, which enables a corrosion-type reaction involving electron transfer from a MoS2site inside the membrane (anode) to another site on membrane surface (cathode) where heavy metal ions are reduced to metallic particles. The membrane surface remains active to efficiently recover metallic particles, because the primary oxidation products are soluble, nontoxic molybdate and sulfur species, which do not form an insulating oxide layer to passivate the membrane surface. Therefore, MoS2membranes can be used effectively to remove and recover precious heavy metals from wastewater.

The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been shown to be valuable prognostic markers for a variety of pathological conditions including solid tumors, sepsis, and others. However, the prognostic values of the NLR and PLR in patients with acute mesenteric arterial embolism (AMAE) and acute mesenteric arterial thrombosis (AMAT) have not been elucidated. The aim of this study was to determine the predictive value of the NLR and PLR for poor prognosis in patients with AMAE and AMAT.

Confined assembly in the intersheet gallery spaces of two-dimensional (2D) materials is an emerging templating route for creation of ultrathin material architectures. Here, we demonstrate a general synthetic route for transcribing complex wrinkled and crumpled topographies in graphene oxide (GO) films into textured metal oxides. Intercalation of hydrated metal ions into textured GO multilayer films followed by dehydration, thermal decomposition, and air oxidation produces Zn, Al, Mn, and Cu oxide films with high-fidelity replication of the original GO textures, including “multi-generational”, multiscale textures that have been recently achieved through extreme graphene compression. The textured metal oxides are shown to consist of nanosheet-like aggregates of interconnected particles, whose mobility, attachment, and sintering are guided by the 2D template. This intercalation templating approach has broad applicability for the creation of complex, textured films and provides a bridging technology that can transcribe the wide variety of textures already realized in graphene into insulating and semiconducting materials. These textured metal oxide films exhibit enhanced electrochemical and photocatalytic performance over planar films and show potential as high-activity electrodes for energy storage, catalysis, and biosensing.

Generating nanovoids/nanochannels in the polyamide rejection layer is an effective method to enhance the separation performance of thin-film composite (TFC) membranes. However, the excessive nanovoids/nanochannels formed in the rejection layer will cause defects and reduce the selectivity. Here we report a secondary interfacial polymerization (SIP) method to decorate the defects caused by one-dimensional (1D) nanochannels, which were generated by etching 1D copper hydroxide nanorods (CuNRs). The obtained SIP-1D NF membrane had a pure water permeability of 8.2 L·m−2·h−1bar−1, while the divalent salts rejection was 92.0 ± 2.6% of Na2SO4, 91.3 ± 0.3% of MgCl2, and 91.8 ± 0.2% of MgSO4. Our work provides experimental basis for 1D nanochannels regulate the structures and properties of NF membrane.

Copper-based nanoparticles are an important class of materials with applications as catalysts, conductive inks, and antimicrobial agents. Environmental and safety issues are particularly important for copper-based nanomaterials because of their potential large-scale use and their high redox activity and toxicity reported from in vitrostudies. Elemental nanocopper oxidizes readily upon atmospheric exposure during storage and use, so copper oxides are highly relevant phases to consider in studies of environmental and health impacts. Here we show that copper oxide nanoparticles undergo profound chemical transformations under conditions relevant to living systems and the natural environment. Copper oxide nanoparticle (CuO-NP) dissolution occurs at lysosomal pH (4–5), but not at neutral pH in pure water. Despite the near-neutral pH of cell culture medium, CuO-NPs undergo significant dissolution in media over time scales relevant to toxicity testing because of ligand-assisted ion release, in which amino acid complexation is an important contributor. Electron paramagnetic resonance (EPR) spectroscopy shows that dissolved copper in association with CuO-NPs are the primary redox-active species. CuO-NPs also undergo sulfidation by a dissolution–reprecipitation mechanism, and the new sulfide surfaces act as catalysts for sulfide oxidation. Copper sulfide NPs are found to be much less cytotoxic than CuO-NPs, which is consistent with the very low solubility of CuS. Despite this low solubility of CuS, EPR studies show that sulfidated CuO continues to generate some ROS activity due to the release of free copper by H2O2oxidation during the Fenton-chemistry-based EPR assay. While sulfidation can serve as a natural detoxification process for nanosilver and other chalcophile metals, our results suggest that sulfidation may not fully and permanently detoxify copper in biological or environmental compartments that contain reactive oxygen species.

The widespread use of silver nanoparticles (Ag-NPs) in consumer and medical products provides strong motivation for a careful assessment of their environmental and human health risks. Recent studies have shown that Ag-NPs released to the natural environment undergo profound chemical transformations that can affect silver bioavailability, toxicity, and risk. Less is known about Ag-NP chemical transformations in biological systems, though the medical literature clearly reports that chronic silver ingestion produces argyrial deposits consisting of silver-, sulfur-, and selenium-containing particulate phases. Here we show that Ag-NPs undergo a rich set of biochemical transformations, including accelerated oxidative dissolution in gastric acid, thiol binding and exchange, photoreduction of thiol- or protein-bound silver to secondary zerovalent Ag-NPs, and rapid reactions between silver surfaces and reduced selenium species. Selenide is also observed to rapidly exchange with sulfide in preformed Ag2S solid phases. The combined results allow us to propose a conceptual model for Ag-NP transformation pathways in the human body. In this model, argyrial silver deposits are not translocated engineered Ag-NPs, but rather secondary particles formed by partial dissolution in the GI tract followed by ion uptake, systemic circulation as organo-Ag complexes, and immobilization as zerovalent Ag-NPs by photoreduction in light-affected skin regions. The secondary Ag-NPs then undergo detoxifying transformations into sulfides and further into selenides or Se/S mixed phases through exchange reactions. The formation of secondary particles in biological environments implies that Ag-NPs are not only a product of industrial nanotechnology but also have long been present in the human body following exposure to more traditional chemical forms of silver.

The decomposed regularity of rare‐earth nitrates in octadecylamine (ODA) is discussed. The experimental results show that these nitrates can be divided into four types. For rare‐earth nitrates with larger RE3+ions (RE=rare earth, La, Pr, Nd, Sm, Eu, Gd), the decomposed products exhibited platelike nanostructures. For those with smaller RE3+ions (RE=Y, Dy, Ho, Er, Tm, Yb), the decomposed products exhibited beltlike nanostructures. For terbium nitrate with a middle RE3+ion, the decomposed product exhibited a rodlike nanostructure. The corresponding rare‐earth oxides, with the same morphologies as their precursors, could be obtained when these decomposed products were calcined. For cerium nitrate, which showed the greatest differences, flowerlike cerium oxide could be obtained directly from decomposition of the nitrate without further calcination. This regularity is explained on the basis of the lanthanide contraction. Owing to their differences in electron configuration, ionic radius, and crystal structure, such a nitrate family therefore shows different thermolysis properties. In addition, the potential application of these as‐obtained rare‐earth oxides as catalysts and luminescent materials was investigated. The advantages of this method for rare‐earth oxides includes simplicity, high yield, low cost, and ease of scale‐up, which are of great importance for their industrial applications.

AbstractA simple, quick and sensitive spectrophotometric method for pipemidic acid, norfloxacin and ciprofloxacin lactate is described, based on a reaction with p-nitrophenol in water medium, apparently by a charge-transfer mechanism, to yield 1:1 complexes with analytically useful maximum absorption at 404 nm, 407nm and 403nm. Optimum conditions for determination, linear calibration range and apparent molar absorptivities have been reported. The methods are highly accurate and have been successfully applied to the determination of pipemidic acid, norfloxacin and ciprofloxacin lactate in tablets. The results are in good agreement with the official methods.

Nanofiltration (NF) with high water flux and precise separation performance with high Li+/Mg2+selectivity is ideal for lithium brine recovery. However, conventional polyamide-based commercial NF membranes are ineffective in lithium recovery processes due to their undesired Li+/Mg2+selectivity. In addition, they are constrained by the water permeance selectivity trade-off, which means that a highly permeable membrane often has lower selectivity. In this study, we developed a novel nonpolyamide NF membrane based on metal-coordinated structure, which exhibits simultaneously improved water permeance and Li+/Mg2+selectivity. Specifically, the optimized Cu–m-phenylenediamine (MPD) membrane demonstrated a high water permeance of 16.2 ± 2.7 LMH/bar and a high Li+/Mg2+selectivity of 8.0 ± 1.0, which surpassed the trade-off of permeance selectivity. Meanwhile, the existence of copper in the Cu–MPD membrane further enhanced anti-biofouling property and the metal-coordinated nanofiltration membrane possesses a pH-responsive property. Finally, a transport model based on the Nernst–Planck equations has been developed to fit the water flux and rejection of uncharged solutes to the experiments conducted. The model had a deviation below 2% for all experiments performed and suggested an average pore radius of 1.25 nm with a porosity of 21% for the Cu–MPD membrane. Overall, our study provides an exciting approach for fabricating a nonpolyamide high-performance nanofiltration membrane in the context of lithium recovery.

Pollutant degradation via periodate (IO4–)-based advanced oxidation processes (AOPs) provides an economical, energy-efficient way for sustainable pollution control. Although single-atomic metal activation (SMA) can be exploited to optimize the pollution degradation process and understand the associated mechanisms governing IO4–-based AOPs, studies on this topic are rare. Herein, we demonstrated the first instance of using SMA for IO4–analysis by employing atomically dispersed Co active sites supported by N-doped graphene (N-rGO-CoSA) activators. N-rGO-CoSA efficiently activated IO4–for organic pollutant degradation over a wide pH range without producing radical species. The IO4–species underwent stoichiometric decomposition to generate the iodate (IO3–) species. Whereas Co2+and Co3O4could not drive IO4–activation; the Co–N coordination sites exhibited high activation efficiency. The conductive graphene matrix reduced the contaminants/electron transport distance/resistance for these oxidation reactions and boosted the activation capacity by working in conjunction with metal centers. The N-rGO-CoSA/IO4–system exhibited a substrate-dependent reactivity that was not caused by iodyl (IO3·) radicals. Electrochemical experiments demonstrated that the N-rGO-CoSA/IO4–system decomposed organic pollutants via electron-transfer-mediated nonradical processes, where N-rGO-CoSA/periodate* metastable complexes were the predominant oxidants, thereby opening a new avenue for designing efficient IO4–activators for the selective oxidation of organic pollutants.