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1.
Hum Genet ; 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38526745

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is a malignant tumor with poor prognosis and high mortality. Although a large number of studies have explored its potential prognostic markers using traditional RNA sequencing (RNA-Seq) data, they have not achieved good prediction effect. In order to explore the possible prognostic signaling pathways leading to the difference in prognosis, we identified differentially expressed genes from one scRNA-seq cohort and four GEO cohorts, respectively. Then Cox and Lasso regression analysis showed that 12 genes were independent prognostic factors for PDAC. AUC and calibration curve analysis showed that the prognostic model had good discrimination and calibration. Compared with the low-risk group, the high-risk group had a higher proportion of gene mutations than the low-risk group. Immune infiltration analysis revealed differences in macrophages and monocytes between the two groups. Prognosis related genes were mainly distributed in fibroblasts, macrophages and type 2 ducts. The results of cell communication analysis showed that there was a strong communication between cancer-associated fibroblasts (CAF) and type 2 ductal cells, and collagen formation was the main interaction pathway.

2.
BMC Neurol ; 24(1): 33, 2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38238684

RESUMO

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disease that affects neuromuscular junction. The literature suggests the involvement of circulating cytokines (CK), gut microbiota (GM), and serum metabolites (SM) with MG. However, this research is limited to observational trials, and comprehensive causal relationship studies have not been conducted. Based on published datasets, this investigation employed Mendelian Randomization (MR) to analyze the known and suspected risk factors and biomarkers causal association of MG and its subtypes. METHODS: This research used two-sample MR and linkage disequilibrium score (LDSC) regression of multiple datasets to aggregate datasets acquired from the genome-wide association studies (GWAS) to assess the association of MG with 41-CK, 221-GM, and 486-SM. For sensitivity analysis and to validate the robustness of the acquired data, six methods were utilized, including MR-Egger regression, inverse variance weighting (IVW), weighted median, and MR-PRESSO. RESULTS: The MR method identified 20 factors significantly associated with MG, including 2 CKs, 6 GMs, and 9 SMs. Further analysis of the factors related to the two MG subtypes, early-onset MG (EOMG) and late-onset MG (LOMG), showed that EOMG had a high overlap with MG in the intestinal flora, while LOMG had a greater similarity in CKs and SMs. Furthermore, LDSC regression analysis indicated that Peptococcaceae, oxidized biliverdin, and Kynurenine had significant genetic correlations with general MG, whereas EOMG was highly correlated with Intestinibacter, while LOMG had significant genetic associations with Kynurenine and Glucose. CONCLUSION: This research furnishes evidence for the potential causal associations of various risk factors with MG and indicates a heterogeneous relationship between CKs, GMs, and SMs with MG subtypes.


Assuntos
Estudo de Associação Genômica Ampla , Miastenia Gravis , Humanos , Cinurenina , Análise da Randomização Mendeliana , Miastenia Gravis/epidemiologia , Miastenia Gravis/genética , Fatores de Risco , Biomarcadores , Citocinas
3.
Environ Sci Technol ; 51(3): 1662-1669, 2017 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-28081362

RESUMO

A closed-loop process to recover lithium carbonate from cathode scrap of lithium-ion battery (LIB) is developed. Lithium could be selectively leached into solution using formic acid while aluminum remained as the metallic form, and most of the other metals from the cathode scrap could be precipitated out. This phenomenon clearly demonstrates that formic acid can be used for lithium recovery from cathode scrap, as both leaching and separation reagent. By investigating the effects of different parameters including temperature, formic acid concentration, H2O2 amount, and solid to liquid ratio, the leaching rate of Li can reach 99.93% with minor Al loss into the solution. Subsequently, the leaching kinetics was evaluated and the controlling step as well as the apparent activation energy could be determined. After further separation of the remaining Ni, Co, and Mn from the leachate, Li2CO3 with the purity of 99.90% could be obtained. The final solution after lithium carbonate extraction can be further processed for sodium formate preparation, and Ni, Co, and Mn precipitates are ready for precursor preparation for cathode materials. As a result, the global recovery rates of Al, Li, Ni, Co, and Mn in this process were found to be 95.46%, 98.22%, 99.96%, 99.96%, and 99.95% respectively, achieving effective resources recycling from cathode scrap of spent LIB.


Assuntos
Carbonato de Lítio , Lítio , Fontes de Energia Elétrica , Eletrodos , Peróxido de Hidrogênio
4.
Front Immunol ; 15: 1300457, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38686387

RESUMO

Background: Extensive evidence suggests a link between alterations in serum metabolite composition and various autoimmune diseases (ADs). Nevertheless, the causal relationship underlying these correlations and their potential utility as dependable biomarkers for early AD detection remain uncertain. Objective: The objective of this study was to employ a two-sample Mendelian randomization (MR) approach to ascertain the causal relationship between serum metabolites and ADs. Additionally, a meta-analysis incorporating data from diverse samples was conducted to enhance the validation of this causal effect. Materials and methods: A two-sample MR analysis was performed to investigate the association between 486 human serum metabolites and six prevalent autoimmune diseases: systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), dermatomyositis (DM), type 1 diabetes (T1D), and celiac disease (CeD). The inverse variance weighted (IVW) model was employed as the primary analytical technique for the two-sample MR analysis, aiming to identify blood metabolites linked with autoimmune diseases. Independent outcome samples were utilized for further validation of significant blood metabolites. Additional sensitivity analyses, including heterogeneity test, horizontal pleiotropy test, and retention rate analysis, were conducted. The results from these analyses were subsequently meta-integrated. Finally, metabolic pathway analysis was performed using the KEGG and Small Molecule Pathway Databases (SMPD). Results: Following the discovery and replication phases, eight metabolites were identified as causally associated with various autoimmune diseases, encompassing five lipid metabolism types: 1-oleoylglycerophosphoethanolamine, 1-arachidonoylglycerophosphoethanolamine, 1-myristoylglycerophosphocholine, arachidonate (20:4 n6), and glycerol. The meta-analysis indicated that three out of these eight metabolites exhibited a protective effect, while the remaining five were designated as pathogenic factors. The robustness of these associations was further confirmed through sensitivity analysis. Moreover, an investigation into metabolic pathways revealed a significant correlation between galactose metabolism and autoimmune diseases. Conclusion: This study revealed a causal relationship between lipid metabolites and ADs, providing novel insights into the mechanism of AD development mediated by serum metabolites and possible biomarkers for early diagnosis.


Assuntos
Doenças Autoimunes , Biomarcadores , Análise da Randomização Mendeliana , Humanos , Doenças Autoimunes/sangue , Doenças Autoimunes/diagnóstico , Biomarcadores/sangue , Metaboloma , Metabolômica/métodos
5.
Waste Manag ; 161: 245-253, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36905812

RESUMO

A one-step system based on mechanochemical activation and the use of grape skins (GS) was proposed to recover metals from lithium-ion batteries (LIBs) cathode waste. The effects of the ball-milling (BM) speed, BM time, and quantity of added GS on the metal leaching rate were explored. The spent lithium cobalt oxide (LCO) and its leaching residue before and after mechanochemistry were characterized by SEM, BET, PSD, XRD, FT-IR, and XPS analysis. Our study shows that mechanochemistry promotes the leaching efficiency of metals from LIBs battery cathode waste by changing the cathode material properties (that is, reducing the LCO particle size (12.126 µm âˆ¼ 0.0928 µm), increasing the specific surface area (0.123 m2/g âˆ¼ 15.957 m2/g), enhancing the hydrophilicity and surface free energy (57.44 mN/m2 âˆ¼ 66.18 mN/m2), promoting the generation of mesoporous structures, refining grains, disrupting the crystal structure, and increasing the microscopic strain, while deflecting the binding energy of the metal ions). A green, efficient and environmentally friendly process for the harmless and resource-friendly treatment of spent LIBs has been developed in this study.


Assuntos
Lítio , Reciclagem , Espectroscopia de Infravermelho com Transformada de Fourier , Reciclagem/métodos , Metais/química , Fontes de Energia Elétrica
6.
Waste Manag ; 156: 247-254, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36502638

RESUMO

Recycling of spent lithium-ion batteries (LIBs) has attracted widespread attention because of their dual attributes to environmental protection and resource conservation. Utilization of strong corrosive acids is currently the preferred way to recover valuable metals from spent LIBs, but the extensive use of chemical reagents can pose serious environmental risks. Herein, this research proposes a green process for selective recovery of lithium using the material of spent LIBs itself without adding exogenous reagents, mechanochemistry induced phase transition. The leaching efficiency of Li can reach 94% by employing the copper foil separated from spent LIBs as the co-grinding additive during the mechanochemical reaction process. Then, the high value LiOH·H2O can be prepared through direct evaporation and crystallization without adding any precipitant. Meanwhile, cobalt is almost remained in the leaching residue which can be recovered through a step-by-step separation process. XRD, XPS, and SEM-EDS characterizations show that LiCoO2 and copper foil are transformed into the soluble Li2O, and insoluble CuO and CoO under the mechanical force. Finally, the soluble Li2O is dissolved in water to prepare the LiOH solution, and the insoluble CuO and CoO are transformed into Cu2O and Co(OH)2. On the basis of the experimental investigation, it is proven that the proposed process is suitable for selectively recovering Li from all types of cathode materials without generating salty wastewater or introducing chemical reagents. Thus, the proposed approach can ensure the efficient recovery of valuable metals from spent LIBs while avoiding the potential threat to the environment and human health.


Assuntos
Cobre , Lítio , Humanos , Fontes de Energia Elétrica , Reciclagem , Eletrodos , Metais , Íons
7.
Waste Manag ; 171: 463-472, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37801873

RESUMO

With the rapid growth of electric vehicles in China, the number of spent power lithium-ion batteries is dramatically increased. Considering the environmental risk, security risk, and potential resource value, China has issued a series of laws and regulations to manage the spent power lithium-ion batteries. This work employs the material flow analysis method to evaluate the material flows of Li, Ni, Co, and Mn during the life cycle of power lithium-ion batteries under the framework of China's recycling policy system. The results show that the demand for primary Li, Ni, Co, and Mn can achieve 26.9, 68.1, 20.4, and 21.9 kt in 2021, and a lot of primary critical resources will inburst the in-use stage. Moreover, the number of secondary Li, Ni, Co, and Mn can achieve 6.1, 15.4, 4.6, and 5 kt in 2021, accounting for 22.7%, 22.6%, 22.5%, and 22.8% of their corresponding demand. Based on the economic evaluation under the framework of China's recycling policy system, it is found that the potential recycling values of Li, Ni, Co, and Mn are approximately 966, 523, 414, and 43 million RMB yuan, which are 66.4%, 71%, 59.6%, and 66.4% higher than those in the absence of China's recycling policy system. It is implied that China's recycling policy system could markedly improve the collection rate by reducing losses and indirectly enhancing the recycling and reuse of spent power lithium-ion batteries. This work is expected to provide guidance for policymakers to improve the management of spent power lithium-ion batteries in China.

8.
Sci Bull (Beijing) ; 67(24): 2541-2549, 2022 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-36604032

RESUMO

Chemically exfoliated nanosheets have exhibited great potential for applications in various electronic devices. Solution-based processing strategies such as inkjet printing provide a low-cost, environmentally friendly, and scalable route for the fabrication of flexible devices based on functional inks of two-dimensional nanosheets. In this study, chemically exfoliated high-k perovskite nanosheets (i.e., Ca2Nb3O10 and Ca2NaNb4O13) are well dispersed in appropriate solvents to prepare printable inks, and then, a series of microcapacitors with Ag and graphene electrodes are printed. The resulting microcapacitors, Ag/Ca2Nb3O10/Ag, graphene/Ca2Nb3O10/graphene, and graphene/Ca2NaNb4O13/graphene, demonstrate high capacitance densities of 20, 80, and 150 nF/cm2 and high dielectric constants of 26, 110, and 200, respectively. Such dielectric enhancement in the microcapacitors with graphene electrodes is possibly attributed to the dielectric/graphene interface. In addition, these microcapacitors also exhibit good insulating performance with a moderate electrical breakdown strength of approximately 1 MV/cm, excellent flexibility, and thermal stability up to 200 â„ƒ. This work demonstrates the potential of high-k perovskite nanosheets for additive manufacturing of flexible high-performance dielectric capacitors.

9.
ACS Appl Mater Interfaces ; 14(16): 18690-18696, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35420779

RESUMO

Metal wires are of great significance in applications such as three-dimensional (3D) printing, soft electronics, optics, and metamaterials. Ga-based liquid metals (e.g., EGaIn), though uniquely combining metallic conductivity, fluidity, and biocompatibility, remain challenging to be spun due to their low viscosity, high surface tension, and Rayleigh-Plateau instability. In this work, we showed that EGaIn as a working electrode could induce the oxidization of EGaIn and interfacial electrochemical polymerization of electroactive monomers (e.g., acrylic acid, dopamine, and pyrrole), thus spinning itself from an opening of a blunt needle. During the spinning process, the high surface tension of EGaIn was reduced by electrowetting and electrocapillarity and stabilized by polymer shells (tunable thickness of ∼0.6-30 µm on wires with a diameter of 90-300 µm), which were chelated with metal ions. The polymeric shells offered EGaIn wires with an enhanced endurance to mechanical force and acidity. By further encapsulating into elastomers through a facile impregnation process, the resultant elastic EGaIn wires showed a combination of high stretchability (up to 800%) and metallic conductivity (1.5 × 106 S m-1). When serving as wearable sensors, they were capable of sensing facial expressions, body movements, voice recognition, and spatial pressure distributions with high sensitivity, good repeatability, and satisfactory durability. Machine-learning algorithms further assisted to detect gestures with high accuracy.

10.
Environ Sci Pollut Res Int ; 28(33): 45867-45878, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33884548

RESUMO

With the rapid promotion of new energy vehicles, in-use electric vehicle batteries (EVBs) are becoming an important component of urban mining. This paper analyzed the metal stocks in EVBs in China from 2009 to 2019 using a bottom-up method, which focused on the in-use stock of seven main metals, namely, nickel, cobalt, manganese, lithium, copper, aluminum, and iron, in primary use stage and secondary use stage of three EVB types, namely, lithium nickel manganese cobalt oxide battery (NMC), lithium iron phosphate battery (LFP), and lithium manganese oxide battery (LMO). It was found that the rapid development of electric vehicles (EVs) contributed to a dramatic increase in in-use metal stocks from 0.7 kt in 2009 to 1.1 Mt in 2019. To assess the increase, three scenarios simulating metal stocks in EVBs from 2020 to 2030 were analyzed, namely, baseline, NMC-dominated, and LFP-dominated, and results indicated that metal stocks will reach 20.6 Mt, 23.2 Mt, and 17.9 Mt, respectively, by 2030. Across the scenarios there is little proportional difference in metal stocks between the two use stages. The proportion of the three EVB types correlates to the development trend of EVB technology under each corresponding scenario. Besides, the in-use metal stocks in EVBs have high implied recycling potential and environmental benefit. The recycling potential of these seven metals is 1.0 Mt in 2019, and it will reach 20.0 Mt, 22.6 Mt, and 17.4 Mt, respectively, in 2030 under the three scenarios. The results reveal the current status and evolution characteristics of metal stocks in EVBs in China, and provide data for material flow analysis and life cycle management of EVBs.


Assuntos
Fontes de Energia Elétrica , Lítio , Eletricidade , Íons , Níquel , Reciclagem
11.
J Colloid Interface Sci ; 556: 239-248, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446337

RESUMO

In this work, carbon-coated manganese silicate (MnSiO3/C) nanocomposite with excellent cycling stability was fabricated via a cost-effective process. The carbon coating followed with a CO2 heat treatment process on the manganese silicate results in mixed-valent hierarchically-porous nanoparticles, which tightly connects with an ultrathin (∼1.5 nm) and ordered carbon coating layer. This composite features rectangular-like cyclic voltammetry curve with two couples of redox peaks, suppressing the irreversible reactions and thus providing a broad and stable working voltage. By fitting the CV curves, the MnSiO3/C demonstrates a capacitive energy-storage behavior. The as-assembled activated carbon//MnSiO3/C asymmetric supercapacitor in 1 M Na2SO4 aqueous electrolyte is found to have excellent cycling stability, with 95.5% retention of initial after 10,000 cycles. This device could deliver 25.8 W h kg-1 energy density at the power density of 1 kW kg-1 with ∼10 mg cm-2 high mass loading, suggesting a bright prospect in practical application.

12.
Waste Manag ; 84: 54-63, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30691913

RESUMO

The production of lithium-ion battery is around 9100 million sets in 2016 and is believed to further increase consecutively. This fact triggers the generation of spent cathode materials which contain metals of both valuable and hazardous. Their recycling corresponding to life cycle sustainability of lithium-ion battery has attracted significant attention. However, most technologies for recycling waste lithium-ion batteries are dependent on metallurgical based processes where secondary pollution is inevitable. This research demonstrates a process to directly regenerate LiNi1-x-yCoxMnyO2 cathode material by incorporating methods of mechanochemical activation and solid-state sintering, which can restore the layered structure and improve the lithium ion diffusion without introducing extra impurities. By understanding the effects of sintering temperature, the optimal conditions for direct regeneration of cathode materials with obvious improvement on electrochemical performance can be obtained. As a result, this research proves the possibility of direct regeneration of nickel-containing waste cathode materials with minimized chemical consumption.


Assuntos
Fontes de Energia Elétrica , Lítio , Eletrodos , Metais , Reciclagem
13.
Waste Manag ; 64: 190-201, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28318961

RESUMO

Lead is classified to be one of the top heavy metal pollutants in China. The corresponding environmental issues especially during the management of spent lead-acid battery have already caused significant public awareness and concern. This research gives a brief overview on the recycling situation based on an investigation of the lead industry in China and also the development of technologies for spent lead-acid batteries. The main principles and research focuses of different technologies including pyrometallurgy, hydrometallurgy and greener technologies are summarized and compared. Subsequently, the circulability of lead based on the entire life cycle analyses of lead-acid battery is calculated. By considering different recycling schemes, the recycling situation of spent lead-acid battery in China can be understood semi-quantitatively. According to this research, 30% of the primary lead production can be shut down that the lead production can still ensure consecutive life cycle operation of lead-acid battery, if proper management of the spent lead-acid battery is implemented according to current lead industry situation in China. This research provides a methodology on the view of lead circulability in the whole life cycle of a specific product and is aiming to contribute more quantitative guidelines for efficient organization of lead industry in China.


Assuntos
Fontes de Energia Elétrica , Chumbo , Reciclagem , China , Metais Pesados
14.
Waste Manag ; 60: 680-688, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27993441

RESUMO

Recycling of spent lithium-ion batteries has attracted wide attention because of their high content of valuable and hazardous metals. One of the difficulties for effective metal recovery is the separation of different metals from the solution after leaching. In this research, a full hydrometallurgical process is developed to selectively recover valuable metals (Ni, Co and Li) from cathode scrap of spent lithium ion batteries. By introducing ammonia-ammonium sulphate as the leaching solution and sodium sulphite as the reductant, the total selectivity of Ni, Co and Li in the first-step leaching solution is more than 98.6% while it for Mn is only 1.36%. In detail understanding of the selective leaching process is carried out by investigating the effects of parameters such as leaching reagent composition, leaching time (0-480min), agitation speed (200-700rpm), pulp density (10-50g/L) and temperature (323-353K). It was found that Mn is primarily reduced from Mn4+ into Mn2+ into the solution as [Formula: see text] while it subsequently precipitates out into the residue in the form of (NH4)2Mn(SO3)2·H2O. Ni, Co and Li are leached and remain in the solution either as metallic ion or amine complexes. The optimised leaching conditions can be further obtained and the leaching kinetics is found to be chemical reaction control under current leaching conditions. As a result, this research is potentially beneficial for further optimisation of the spent lithium ion battery recycling process after incorporating with metal extraction from the leaching solution.


Assuntos
Amônia/química , Fontes de Energia Elétrica , Metais/isolamento & purificação , Reciclagem/métodos , Eletrodos , Cinética , Lítio , Metais/química , Sulfitos , Temperatura , Fatores de Tempo , Difração de Raios X
15.
Biointerphases ; 11(3): 031006, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27440396

RESUMO

Calcium phosphate coatings were prepared on the surface of self-designed Mg-Zn-Ca-Mn alloy using microarc oxidization technology. To characterize the microstructures, cross-section morphologies, and compositions of the coatings, the authors used scanning electron microscopy equipped with an energy-disperse spectrometer, x-ray diffraction, and Fourier transform infrared spectroscopy. Potentiodynamic polarization in the simulated body fluid (SBF) was used to evaluate the corrosion behaviors of the samples. An SBF immersion test was used to evaluate the coating bioactivity and degradability. After the immersion tests, some bonelike apatite formed on the coating surfaces indicate that bioactivity of the coatings is excellent. The coating prepared in electrolyte containing (NaPO3)6 had slower degradation rate after immersion test for 21 days.


Assuntos
Ligas/química , Cimentos Ósseos/química , Materiais Revestidos Biocompatíveis/química , Fosfatos/análise , Propriedades de Superfície , Ligas/farmacologia , Cimentos Ósseos/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
16.
Chemosphere ; 152: 415-22, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26999751

RESUMO

The NiFe layered double hydroxides (LDHs) with different mole ratio of Ni/Fe (4:1, 3:1, 7:3 and 1:1) were prepared by a simple coprecipitation method. The adsorption performance were evaluated by the removal of methyl orange (MO) dye and hexavalent chromium(VI) heavy metal ion. It is found that Ni4Fe1-LDH can remove more than 92% of MO in 10 min at the 10 mg/L MO initial concentration, and 97% of Cr(VI) in 1 h at 4 mg/L Cr2O7(2-) initial concentration. The saturated adsorption capacity of Ni4Fe1-LDH is found to be as large as 205.76 mg/g for MO and 26.78 mg/g for Cr(VI). The adsorption behavior of this new adsorbent is fitted well with Langmuir isotherm and the pseudo-second-order kinetic model, indicative of a monolayer and chemical adsorption that synergistically originates from exchangeable anions mechanism and layer charge density. Due to the excellent removal capacity of MO and Cr(VI), the NiFe-LDHs could be a promising adsorbent for wastewater treatment.


Assuntos
Compostos Azo/química , Cromo/química , Hidróxidos/química , Ferro/química , Níquel/química , Poluentes Químicos da Água/química , Adsorção , Cinética , Modelos Teóricos , Eliminação de Resíduos Líquidos/métodos
17.
Talanta ; 134: 16-23, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25618635

RESUMO

Carbon dots capped with polyethyleneimine (CD-PEI) were synthesized and applied in selective separation and preconcentration of trace Cr(VI). Dispersed particle extraction (DPE) slurry sampling with flame atomic absorption spectrometry (FAAS) was used to selectively and sensitively determine Cr(VI) in water samples. The as-synthesized CD-PEI was confirmed by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, elemental analysis, fluorescence and zeta potential measurement. The adsorption of Cr(VI) on CD-PEI was evaluated. Its isothermal adsorption was studied and fitted in the Langmuir model. Nearly 85% of Cr(VI) was adsorbed within 10 min showed that the CD-PEI exhibited fairly fast kinetics for the sorption of Cr(VI). Experimental conditions, including the content and size of CD-PEI, sample pH, adsorption time, sample volume, slurry volume and interfering ions, were further optimized to obtain efficient preconcentration and high-precision determination of Cr(VI). CD-PEI with small size turned to be a good candidate for the preparation of slurry. CD-PEI served not only as a promising adsorbent for separation and preconcentration of Cr, but also a signal-enhancing agent in FAAS. The method achieved an enhancement factor of 30 and a detection limit (S/N=3) of 0.21 µg L(-1) Cr(VI) with a consumption of 14.0 mL sample and an adsorption time of 5 min, which provided two times of signal enhancement. The RSD for 11 replicate measurements of 5.0 µg L(-1) Cr(VI) was 2.8%. The possible signal enhancement mechanism was proposed. The developed method has been applied to determine trace Cr(VI) in a variety of water samples.

18.
Anal Chim Acta ; 861: 12-24, 2015 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-25702270

RESUMO

Five-way high performance liquid chromatography-diode array detection (HPLC-DAD)-kinetic-pH data were obtained by recording the kinetic evolution of HPLC-DAD signals of samples at different pH values and a new fourth-order calibration method, alternating quinquelinear decomposition (AQQLD) based on pseudo-fully stretched matrix forms of the quinquelinear model, was developed. Simulated data were analyzed to investigate the performance of AQQLD in comparison with five-way parallel factor analysis (PARAFAC). The tested results demonstrated that AQQLD has the advantage of faster convergence rate and being insensitive to the excess component number adopted in the model. Then, they have been successfully applied to investigate quantitatively the kinetics of naptalam (NAP) hydrolysis in two practical systems. Additionally, the serious chromatographic peak shifts were accurately corrected by means of chromatographic peak alignment method based on abstract subspace difference. The good recoveries of NAP were obtained in these samples by selecting the time region of chromatogram. The elution time, spectral, kinetic time and pH profiles resolved by the chemometric techniques were in good agreement with experimental observations. It demonstrates the potential for the utilization of fourth-order data for some complex systems, opening up a new approach to fourth-order data generation and subsequent fourth-order calibration.

19.
Waste Manag ; 34(9): 1715-24, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24973865

RESUMO

To solve the recycling challenge for aqueous binder based lithium-ion batteries (LIBs), a novel process for recycling and resynthesizing LiNi1/3Co1/3Mn1/3O2 from the cathode scraps generated during manufacturing process is proposed in this study. Trifluoroacetic acid (TFA) is employed to separate the cathode material from the aluminum foil. The effects of TFA concentration, liquid/solid (L/S) ratio, reaction temperature and time on the separation efficiencies of the cathode material and aluminum foil are investigated systematically. The cathode material can be separated completely under the optimal experimental condition of 15vol.% TFA solution, L/S ratio of 8.0 mL g(-1), reacting at 40°C for 180 min along with appropriate agitation. LiNi1/3Co1/3Mn1/3O2 is successfully resynthesized from the separated cathode material by solid state reaction method. Several kinds of characterizations are performed to verify the typical properties of the resynthesized LiNi1/3Co1/3Mn1/3O2 powder. Electrochemical tests show that the initial charge and discharge capacities of the resynthesized LiNi1/3Co1/3Mn1/3O2 are 201 mAh g(-)(1) and 155.4 mAh g(-1) (2.8-4.5 V, 0.1C), respectively. The discharge capacity remains at 129 mAh g(-1) even after 30 cycles with a capacity retention ratio of 83.01%.


Assuntos
Resíduo Eletrônico , Óxidos/síntese química , Reciclagem/métodos , Alumínio , Cobalto , Eletrodos , Lítio , Manganês , Níquel , Temperatura , Ácido Trifluoracético
20.
Adv Mater ; 24(17): 2349-52, 2012 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-22499287

RESUMO

Random composites with nickel networks hosted randomly in porous alumina are proposed to realize double negative materials. The random composite for DNMs (RC-DNMs) can be prepared by typical processing of material, which makes it possible to explore new DNMs and potential applications, and to feasibly tune their electromagnetic parameters by controlling their composition and microstructure. Hopefully, various new RC-DNMs with improved performance will be proposed in the future.


Assuntos
Óxido de Alumínio/química , Níquel/química , Campos Magnéticos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Porosidade
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