An efficient separation method is crucial for recovering low-value iron from the spent pickling solutions as valuable materials. In this study, selective separation of Fe(III) from the spent pickling effluent was achieved through anti-synergistic solvent extraction, where Cyanex923 and TBP were used as the extractants. The extraction of both Fe(III) and Zn(II) was depressed owing to the molecular interaction between TBP and Cyanex923, but this anti-synergistic role is more evident for zinc. The separation coefficient of Fe(III)/Zn(II) can be improved from 125 to 525 when 0.2 mol/L TBP was mixed with 0.1 mol/L Cyanex923. The structures of the organic phase before and after extraction were disclosed by UV–vis, FT-IR, and SAXS spectroscopies. The addition of TBP can boost Fe(III) stripping because the molecular interaction impairs the combining capacity between Fe(III) and Cyanex923. Moreover, the loaded Fe(III) was recovered as the ferric phosphate precipitates. Therefore, the interaction between Cyanex923 and TBP enhances the separation of Fe(III)/Zn(II) and promotes Fe(III) stripping, thus realizing its efficient recovery and utilization. These results will contribute to the efficient treatment and recycling of spent pickling liquors.

The performance of Li-ion batteries (LIBs) at sub-ambient temperatures is limited by the resistive interphases due to electrolyte decomposition, particularly on the anode surface. In this study, lithium fluorosulfonate (LFS) was added to commercial electrolytes to enhance the low-temperature electrochemical performance of LiFePO4 (LFP)/graphite (Gr) pouch cells. The addition of LFS significantly reduced the charge transfer resistance of the anode, substantially extending the cycle life and discharge capacity of commercial LFP/Gr pouch cells at -10 and -30 degrees C. Compared with the capacity retention rate of the baseline electrolyte at -10 degrees C (80 % after 25cycles), the capacity retention rate of the LFS electrolyte after 100 cycles under 0.5 C/0.5 C was retained at 94 %. Further mechanistic studies showed that the LFS additive induced the formation of a solid electrolyte interphase (SEI) film comprising inorganic-rich LiF, Li2SO4, and additional organic fluorides and sulfides to maintain good stability at the Gr/electrolyte interface during low-temperature operation. LFS suppressed electrolyte decomposition by forming a robust and low-resistance SEI film on the anode. These results demonstrate that LFS is a promising electrolyte additive for low-temperature LFP/Gr pouch cells.

Safe and fast charging is important for graphite/lithium iron phosphate (Gr/LFP) batteries in the fast-growing electric vehicle industry. However, conventional carbonate-based electrolytes produce an obstructive solid-electrolyte interface (SEI), which hinders the fast charging of lithium-ion batteries (LIBs). In this study, a unique tri-methylsilyl-2-(fluorosulfonyl)difluoroacetate (TMSFS) additive was introduced to regulate the SEI of Gr/LFP batteries containing a lithium bis(fluorosulfonyl)imide-based electrolyte during fast charging. The addition of TMSFS significantly reduced the charge-transfer resistance of the anode, substantially extending the cycle life of commercial Gr/LFP batteries to over 1000 cycles at 2C rate, which was far superior to that of the baseline electrolyte (< 530 cycles). Further mechanistic studies showed that the inorganic fluorinated and sulfurized species formed on the SEI film stabilized the intermediate lithium carbonate from attack by the side-reaction products. TMSFS acts as a film-forming additive, curbing electrolyte decomposition, and fortifying the structural integrity of the electrode through the formation of a robust and low-impedance SEI film on the anode. These results provide a simple and effective strategy for combining F and S via electrolyte optimization to implement commercially safe fast-charging LIBs.

The massive combustion of non-renewable fossil fuels causing global warming has raised concerns. However, fuel cells, including proton exchange membrane fuel cells, face challenges such as short lifespan and high cost, hindering their large-scale commercialization. The objective of this paper is to explore the growth, practical utilization, concerns, and enhancement techniques of proton exchange membrane fuel cells, which are a promising source of renewable energy. Research indicates that the lifespan of Proton Exchange Membrane fuel cells (PEMFC) is influenced by the conditions of the reaction environment. The high expenses associated with these cells can be largely attributed to the inflammability and explosiveness of hydrogen, the primary raw material, which can present transportation challenges. Moreover, the use of precious metals as reaction catalysts can result in poisoning, which restricts their application to a narrow spectrum. In conclusion, further improvements are necessary for the future application of PEMFC. More innovations are needed to expand the application areas by using more efficient and safe materials that are easier to transport. To broaden the way for the future development of green new energy. This paper is a valuable resource for improving proton exchange membrane fuel cell technology.

CoCrFeNi HEAs have better ductility, while the strength and corrosion resistance need to be further improved, while metal materials for deep-sea operations put forward the requirement of excellent mechanical properties and very high corrosion resistance; however, CoCrFeNi HEAs have been less studied for the trade-off between mechanical properties and corrosion resistance. Therefore, the present study utilized the laser melting deposition (LMD) technique to fabricate a series of (CoCrFeNi)Tix (x = 0.2, 0.4, 0.6, 0.8, 1.0 at.%) HEAs and systematically investigated the influence of Ti content on the alloy’s microstructure, phase composition, mechanical properties, and electrochemical performance. The research findings revealed that as the Ti content increased, the alloy gradually transformed from a single face-centered cubic (FCC) phase to an FCC and body-centered cubic (BCC) dual-phase structure. The addition of Ti induced a transition in the alloy’s microstructure from an equiaxed to a dendritic morphology, accompanied by grain refinement. Energy dispersive spectroscopy analysis confirmed the uniform distribution of Ti within the alloy. The hardness of the alloy increased significantly with the increase in Ti content, reaching 804.5 HV when the Ti content was 1.0 at.%, which was 4.13 times higher than the Ti-free alloy. The tensile and compression test results showed that the (CoCrFeNi)Tix alloy with a Ti content of 0.4 at.% exhibited the best overall mechanical performance. The electrochemical test results indicated that the addition of Ti effectively enhanced the corrosion resistance of the alloy, with the 0.4 at.% Ti-containing alloy exhibiting the optimal corrosion resistance. This study provides a strong theoretical and experimental foundation for the design of high-performance CoCrFeNi-based HEAs.

Ni-rich LiNixCoyMn1_x_yO2/graphite batteries with Ni >= 0.8 have aroused great interest in high-energy-density Li-ion batteries. However, their practical applications still face huge challenges owing to severe capacity fading on unstable cathodic solid electrolyte interfaces (SEI). Herein, we propose an advanced electrolyte additive, tri(2-furyl)phosphine (FuP), to induce the simultaneous formation of robust SEI films on cathode and anode surfaces. This interphase can significantly improve the cyclability of commercial LiNi0.8Co0.1Mn0.1O2/graphite pouch cells at 45 degrees C and reduce cell impedance during cycling. The capacity retention rate of the cells with the FuP-based electrolyte can reach 90 % after 600 cycles, which is considerably better than that of baseline batteries (70 %). Mechanistic studies indicate that FuP suppresses the formation of fragile Li2CO3 to generate more stable LiF, LixPOyFz, and additional organic phosphorus species on the electrode surface, thereby preventing cation disorder and irreversible phase transitions. These results provide a facile and efficient strategy for enhancing the per-formance of Ni-rich Li-ion batteries.

The scaling of silicon-based transistors at sub-ten-nanometre technology nodes faces challenges such as interface imperfection and gate current leakage for an ultrathin silicon channel 1 , 2 . For next-generation nanoelectronics, high-mobility two-dimensional (2D) layered semiconductors with an atomic thickness and dangling-bond-free surfaces are expected as channel materials to achieve smaller channel sizes, less interfacial scattering and more efficient gate-field penetration 1 , 2 . However, further progress towards 2D electronics is hindered by factors such as the lack of a high dielectric constant ( κ ) dielectric with an atomically flat and dangling-bond-free surface 3 , 4 . Here, we report a facile synthesis of a single-crystalline high- κ ( κ of roughly 16.5) van der Waals layered dielectric Bi 2 SeO 5 . The centimetre-scale single crystal of Bi 2 SeO 5 can be efficiently exfoliated to an atomically flat nanosheet as large as 250 × 200 μm 2 and as thin as monolayer. With these Bi 2 SeO 5 nanosheets as dielectric and encapsulation layers, 2D materials such as Bi 2 O 2 Se, MoS 2 and graphene show improved electronic performances. For example, in 2D Bi 2 O 2 Se, the quantum Hall effect is observed and the carrier mobility reaches 470,000 cm 2 V −1 s −1 at 1.8 K. Our finding expands the realm of dielectric and opens up a new possibility for lowering the gate voltage and power consumption in 2D electronics and integrated circuits.

This work demonstrates the successful additive manufacturing of an in situ-alloyed CoCrFeNi HEA with a single phase (FCC) structure via the laser metal deposition (LMD) technique. In this work, bulk specimens of the CoCrFeNi high entropy alloy (HEA) of size 15 mm × 15 mm × 45 mm were additive-manufactured (AMed). An H320-type additive-subtractive manufacturing all-in-one system with a 2 kW fiber laser with a coaxial nozzle head integrated in a five-axis CNC machine was used. The effect of varying laser powers (1000 W, 1300 W, and 1600 W) on the microstructure and mechanical and electrochemical properties of the AMed HEA specimens was investigated. The AMed specimens were analyzed for their microstructure, elemental distributions, microhardness, and mechanical and electrochemical properties. An increase in the laser power led to a non-uniform cooling rate and non-steady solidification rates of the molten area during the AM process. As a result, the crystal constant decreased, and the microhardness fluctuated within a narrow range across the specimen. Among the three laser powers, the AMed CoCrFeNi HEA at 1300 W had the optimal mechanical properties and the best electrochemical behavior in 3.5 wt.% NaCl solution.

Soil–bentonite (S-B) materials are promising backfill materials for use as engineered barriers in heavy metal-contaminated sites. The effects of contaminant exposure on the retention performance of the S-B barrier remain unrevealed. In this study, based on the pollution status of an abandoned ferroalloy factory located in southern China, the retention performance of the S-B mixture toward Cr(VI) and Zn(II) was studied through adsorption and diffusion experiments sequentially; the separate effect of ionic strength (binary solution) and the combined effect of ionic strength and associated heavy metal ion (ternary solution) were discussed. In NaCl–Cr(VI)/Zn(II) binary solutions, the adsorption of Zn(II) onto the S-B mixture is larger than that of Cr(VI). K d , Q max , and ɛ acc (accessible porosity) of Cr(VI) increase through increasing ionic strength, while Zn(II) shows the opposite trend; D e (effective diffusion coefficient) values for both Cr(VI) and Zn(II) increased with increasing ionic strength and follow a sequence of Cr(VI) > Zn(II), indicating a better retention performance of the S-B mixture to Zn(II). For a given ionic strength, the adsorption of Zn(II) was larger than that of Cr(VI), which can be attributed to the retention specificity of the S-B mixture to anion and cation. In Cr(VI)–Zn(II)–NaCl ternary solutions, the adsorptions of Cr(VI) and Zn(II) are enhanced in varying degrees when compared with their binary solution, which probably could be attributed to the ion bridge role of Cr(VI)/Zn(II) to connect each other that relatively increased the adsorption capacity of S-B material. This work will contribute to an in-depth understanding of the retention performance of the S-B mixture in complicated chemical environments and facilitate the selection of future remediation strategies.

Graphene was introduced into C/C–SiC composites via pressureless impregnation to enhance the mechanical and thermal properties of the composites. The effects of various graphene contents on the mechanical and ablative performances of C/C–SiC composites were investigated. The results showed that the ultimate bending stress and compressive stress of the C/C–SiC composites increased by 28.98% and 23.64%, respectively, after adding 7.25% graphene. Moreover, the ablation rates of the composites were vastly decreased after adding a slight graphene content (2.13%). However, the ablation rates increased with increasing of graphene content, indicating that the benefit of introducing graphene on the ablation property decreased, which was mainly ascribed to the relative reduction in the SiC content. As a result, introducing slight graphene into C/C–SiC composites had the greatest benefit on the anti-ablation performance.

The spent hydroprocessing (HDP) catalysts containing a considerable quantity of oily pollutants and valuable metals including nickel (Ni), molybdenum (Mo), and vanadium (V) are hazardous wastes to be treated urgently. Herein, a sustainable process featuring vacuum pyrolysis and fast acidic elution was proposed to recycling the residual oils and metal values from the uncrushed spent HDP catalysts. The removal efficiency of oils by vacuum pyrolysis reached more than 85% at 400 C in 60 min. The Ni, Mo, and V deposited on the uncrushed catalysts were fast eluted and recovered by 1 mol/L sulfuric acid solution within 15 min. The ultrasound-assisted leaching could promote metal recovery within 10 min but then has no difference with stirring leaching. The leaching efficiencies of Ni, Mo, and V reached over 95% with few Al being dissolved (7.63%). The obtained uncrushed Al2O3 residue could be potentially recycled as the support for a fresh catalyst. The liquid film diffusion control mechanism was disclosed to represent the fast leaching process of metal values. These results provided a promising and green approach for the sustainable recovery of both residual oils and valuable metals from spent hydroprocessing catalysts.

Recovering metal values in hazardous spent hydrogenation catalysts is of vital economic and environmental importance. Herein, the selective recovery of valuable molybdenum (Mo), vanadium (V), and nickel (Ni) from spent hydroprocessing catalysts are achieved by using a sulfuric acid leaching-stepwise extraction process. After roasting in the air at 400 ?C, the valuable metals are effectively leached within 20 min by 1 mol/L sulfuric acid at 75 ?C. The leaching efficiency of Al, Ni, Mo, and V is 22.16%, 99.44%, 98.59%, and 100%, respectively. Based on the species analysis of the leachate, a stepwise extraction separation route was established for selective recovery of Mo, Ni, and V from the acidic leachate. Mo and V are preferentially co-extracted by the mixed TOA/Cyanex272 with a molar ratio of 7:3, which exhibits an excellent extraction selectivity over Ni and Al. Increasing the concentration of Cyanex272 in the mixed system can effectively improve the selective stripping of vanadium but slightly inhibit its extraction. Residual Ni in the raffinate can be selectively separated by 50%(V/V) commercial HBL110 with an extraction efficiency of 98.5%. Especially, the reductive sodium sulfite can greatly enhance the selective stripping of vanadium from the loaded organic phase. Residual Mo in the organic phase can be well stripped with an alkaline solution. The selective stripping mechanism of vanadium is revealed by the FT-IR and Raman spectra. This work proposes a sustainable stepwise separation route for recovering valuable metals in the spent hydroprocessing catalyst.

In the present work, we review the methods employed in the investigation of solvent extraction mechanism. The employment of slope-analysis traditional methods in extraction were accomplished based on chemical equilibrium, the stoichiometry of extracted complexes and gained no definitive structural information of the extracted complexes. The application of molecular vibration spectrum, electrospray ionization mass spectrometry, nuclear magnetic resonance, X-ray single crystal diffraction, synchrotron radiation X-ray absorption spectrometry, etc. modern analytical techniques in the investigation of solvent extraction also provide the coordination structure of the extracted species formed during the extraction process. However, not every analytical technique is available, such as synchrotron radiation X-ray absorption spectrometry, the most effective method to study the structure of short-range ordered systems such as amorphous samples and solutions, while others employed in the investigation of the solid structure which is not suitable for solvent extraction. The combination of X-ray single crystal diffraction and modern spectral techniques provide new directions in the investigation of solvent extraction mechanism.

采用沉淀法制备水合氧化锆吸附剂,研究水合氧化锆吸附模拟硫酸锰溶液中氟离子的性能.考察不同实验条件下水合氧化锆对氟的吸附效果的影响,并利用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)手段对吸附剂吸附前、后的形貌进行表征及对吸附机理进行分析.研究结果表明:在含锰90.39 g/L、氟50 mg/L的硫酸锰溶液中,水合氧化锆最佳吸附条件为pH=4.0,吸附剂用量为2 g/L,吸附时间为8 h,在吸附温度为20℃时,吸附后溶液中残留氟质量浓度为8.54 mg/L,锰损失与溶液中锆残留量均很低.实验数据与拟二级动力学模型及Freundlich吸附等温模型所得结果高度拟合.升温有利于吸附,35℃下理论最大平衡吸附容量为77.64 mg/g.氟离子通过与吸附剂上羟基发生离子交换而被去除.水合氧化锆是适用于电池级硫酸锰溶液中氟吸附脱除的有效材料.

With the use of a novel precursor, SiC granules together with nanofibers were grown in situ in C/C felt utilizing sol–gel and precursor impregnation and pyrolysis methods. The results showed that the precursor possessed low residual carbon after the carbothermal reduction reaction. Moreover, owing to the gas–gas reaction between SiO and CO, the generated SiC largely filled the microvoids in the regions of the non‐woven layer. Furthermore, the in situ grown SiC of the composites was more continuous than the nubby SiC of polycarbosilane because of the uniform filling of SiC particles and nanofibers. All these factors are conducive to the formation of a compact layer of SiO 2 during ablation by increasing the molten glass and impeding the infiltration of O 2 . As a result, the fabricated C/C–SiC composites exhibited better ablation resistance, and the linear and mass ablation rates were 7.284 ± 0.307 μm s −1 and 0.218 ± 0.023 mg s −1 , respectively, after ablation for 120 s.

Lately, a series of adsorbents with conjugated structures were developed and found to be efficient for the removal of seriously hazardous radionuclide iodine. Herein, we present designed two novel cyclophosphazene-based electron-enriched pi-conjugation hybrid polymers on the basis of the Friedel-Craft alkylation cross-linking strategy between hexachlorocyclotriphosphazene and thiophene or pyrrole, which was correspondingly abbre-viated as CPP-Tp and CPP-Pyr. CPP-Tp and CPP-Pyr displayed excellent volatile iodine capture capacity up to 346 wt% and 297 wt%, respectively. Remarkably, in spite of the poor porosity, CPP-Tp presented outstanding iodine capture capacity per unit BET surface area up to 68 wt% comparing to the known iodine adsorbents to date, due to the strong chemical affinity between iodine molecules and the electron-enriched groups (hetero -atoms and pi-conjugated heterocyclic rings) in the frameworks. Besides, both CPP-Tp and CPP-Pyr showed rapid adsorption rate and high removal efficiency towards iodine in hexane solutions, and the maximum iodine adsorption capacities were also correspondingly calculated to be 588 mg/g and 625 mg/g for CPP-Tp and CPP-Pyr according to the Langmuir model. In addition, both CPP-Tp and CPP-Pyr exhibited favorable regeneration and recycle ability, indicating the cyclophosphazene-based conjugated CPP-Tp and CPP-Pyr might become one of potential candidates for the removal of iodine in the future.

A novel precursor of SiC prepared by mixing boron phenolic resin and hydrolytic solution of tetraethyl orthosilicate was employed to fabricate the ablation-resistant C/C-SiC composites. The pyrolysis behaviors of pre cursor and the ablation properties of prepared composites were discussed. Results show that during the pyrolyzation process of the precursor, the carbon phase was evenly surrounded by the silica phase, benefitting the occurrence of the carbothermal reaction. The precursor was totally transformed into SiC with the carbon left (7.77-8.11 wt%) after heating at 1600 degrees C. Due to the unique surrounded structure between the carbon and silica phases, part of the residual carbon was encircled by the generated SiC ceramics. During ablation, the carbon nucleus played a positive role in enhancing ablation resistance of composites by hindering the flow of molten silica. Compared with the composites employed polycarbosilane as precursor, this prepared C/C-SiC composites exhibited a decent anti-ablation performance.

A cyclophosphazene-based amino functionalized hybrid polymer, NH2-CPP, was successfully prepared by a facile single-step refluxing method via the polycondensation of hexachlorocyclotriphosphazene and 1,4-benzenediamine. The synthesized NH2-CPP was characterized as various-sized microsphere with excellent positive charged surface. Taking account of the promising performance of NH2-CPP, it was lately applied for removing Cr (VI) from aqueous solutions, and the probable adsorption behavior towards Cr(VI) was successively investigated. The results demonstrated that Langmuir isotherm model and pseudo-second order kinetic model could be adequately fitted the adsorption process. The maximum adsorption capacity of NH2-CPP for Cr(VI) was correspondingly fitted to be up to 148.59 mg/g at initial pH 4.0 and 253.81 mg/g at initial pH 2.0, presenting comparable even superior Cr(VI) removal performance than majority of adsorbents reported up to date. Significantly, NH2-CPP exhibited relatively superior removal efficiency towards Cr(VI) and 40 min was enough to achieve adsorption equilibrium. Additionally, NH2-CPP can efficiently remediate low-concentration Cr(VI)containing solutions (0.5-50 mg/L) to satisfy the maximum discharge permission concentration (less than 0.1 mg/L).

The Cu(II) separation behaviors with polymer inclusion membranes (PIMs) are explored by modifying 2-aminomethylpyridine derivatives with hydrophobic alkyl chains, including 2-[N-(tert-butyloxycarbonylmethyl)- 2-picolyamino]acetate (AMB), N,N-dioctyl-2-aminomethylpyridine (AMD), tert-butyl 2-(N-octyl-2-picolyamino) acetate (AMC), and N,N-didecyl-2-aminomethylpyridine (AME). The transport flux and selectivity of Cu(II) are determined by optimizing composition and structure of carriers and plasticizers. The results show that the hydrophobic modification of 2-aminomethylpyridine derivatives can boost the selective transport of copper ions in PIMs and membrane stability. In the optimum composition of 30 wt.% PVC, 30 wt.% AME, and 40 wt.% NPOE, the initial flux of Cu(II) is 5.8×10−6 mol·m−2·s−1. The FT-IR and XPS spectra identify that the alkyl amine functional groups of AME involve in the transport of copper chloride species. The SAXS analysis demonstrates that the generated micro-channels in PIMs induced by the hydrophobic modification of 2-aminomethylpyridine derivatives can contribute to the enhanced Cu(II) flux.

Novel cyclophosphazene-based amino-linked porous polymers (CPP-1 and CPP-2) were successfully prepared via a facile one-step strategy, which involved the polycondensation between hexachlorocyclotriphosphazene and pphenylenediamine. Triethylamine and flake-like solid KOH were used as acid acceptor, respectively. Interestingly, it was demonstrated that KOH played a significant role during the fabrication of CPP-2, causing the formation of agglomerated hollow flakes with hierarchical porosity. Thus, the possible synthetic pathway of CPP-2 was discussed in detail and named as in-situ template strategy. The iodine capture performance was also systematically investigated. The results showed that CPP-2 presented favorable volatile iodine capture capacity reach up to 271 wt% and exhibited promising iodine removal efficiency in n-hexane solution. Moreover, the iodine-loaded CPPs@I2 can be easily regenerated by ethanol, and maintained with satisfactory iodine capture performance even after five cycles.