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1.
Chemistry ; 30(13): e202303424, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38116816

RESUMO

High-efficacy recycling of spent lithium cobalt oxide (LiCoO2 ) batteries is one of the key tasks in realizing a global resource security strategy due to the rareness of lithium (Li) and cobalt (Co) resources. However, it is of great significance to develop the innovative recycle methods for spent LiCoO2 , simultaneously realizing the efficient recovery of valuable elements and the regeneration of high-performance LiCoO2 . Herein, a novel strategy of regenerating LiCoO2 cathode is proposed, which involves the preparation of micro-spherical aluminum (Al)-doped lithium-lacked precursor (Li2x Co1-x-y Al2/3y CO3, remarked as "PLCAC") via ammonium bicarbonate coprecipitation. The comprehensive conditions affecting particle growth kinetics, morphology and particle size the has been investigated in detail by physical characterizations and electrochemical measurements. And the optimized Al-doped LiCoO2 materials with high-density sphericity (LiCo1-z Alz O2 , remarked as "LCAO") shows a high initial specific capacity of 161 mAh g-1 at 0.1 C and excellent capacity retention of 99.5 % within 100 cycles at 1 C in the voltage range of 2.8 to 4.3 V. Our work provides valuable insights into the featured design of LiCoO2 precursors and cathode materials from spent LiCoO2 batteries, potentially guaranteeing the high-efficacy recycling and utilization of strategic resources.

2.
Chemphyschem ; 25(13): e202400064, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38575386

RESUMO

Layered Ni-rich oxides (LiNi1-x-yCoxMnyO2) cathode materials are of current interest in high-energy-demanding applications, such as electric vehicles because of high discharge capacity and high intercalation potential. Here, the effect of co-doping a small amount of Ti and Ta on the crystal structure, morphology, and electrochemical properties of high Ni-rich cathode material LiNi0.8Mn0.1Co0.1-x-yTixTayO2 (0.0≤x+y≤0.2) was systematically investigated. This work demonstrates that an optimum level of Ti and Ta doping is beneficial towards enhancing electrochemical performance. The optimal Ti4+ and Ta5+ co-doped cathode LiNi0.8Mn0.1Co0.09Ti0.005Ta0.005O2 exhibits a superior initial discharge capacity of 161.1 mAh g-1 at 1 C, and excellent capacity retention of 87.1 % after 250 cycles, compared to the pristine sample that exhibits only 59.8 % capacity retention. Moreover, the lithium-ion diffusion coefficients for the co-doped cathode after the 3rd and 50th cycles are 9.9×10-10 cm2 s-1 and 9.3×10-10 cm2 s-1 respectively, which is higher than that of the pristine cathode (3.3×10-10 cm2 s-1 and 2.5×10-10 cm2 s-1 respectively). Based on these studies, we conclude that Ti and Ta co-doping enhances structural stability by mitigating irreversible phase transformation, improving Li-ion kinetics by expanding interlayer spacing, and nanosizing primary particles, thereby stabilizing high-nickel cathode materials and significantly enhancing cyclability.

3.
Nanotechnology ; 35(23)2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38364270

RESUMO

Iron oxide nanoparticles (IONPs) exhibit unique magnetic properties and possess a high surface-to-volume ratio, making them ideal candidates for the conjugation of substances, including enzymes. Laccase (EC 1.10.3.2), an oxidative enzyme with diverse applications, presents an opportunity for enhancing stability and reusability through innovative immobilization techniques, thus reducing overall process costs. In this study, we employed a direct binding procedure via carbodiimide activation to conjugate laccase onto IONPs synthesized using thermal chemical coprecipitation. Stabilization of the nanoparticles was achieved using thioglycerol and polyvinyl alcohol (PVA) as capping agents. Characterization of the synthesized nanoparticles was conducted using UV-spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy. FTIR spectroscopy analysis confirmed successful laccase binding to magnetic nanoparticles, with binding efficiencies of 90.65% and 73.02% observed for thioglycerol and PVA capped IONPs, respectively. Furthermore, the conjugated enzyme exhibited remarkable stability, retaining nearly 50% of its initial activity after 20 reuse cycles. This research demonstrates that immobilizing laccase onto IONPs enhances its activity, stability, and reusability, with the potential for significant cost savings and expanded applications in various fields.

4.
J Fluoresc ; 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38888658

RESUMO

Metal nanoparticles and their binary oxides are well-known for their interactions with biomolecules and their applications in the biomedical field. However, the potential of ternary oxide nanophosphors remains underexplored in these fields due to challenges associated with high-temperature synthesis procedures and the use of toxic chemicals. ZnAl2O4, a ternary oxide matrix, being recognized for its adjustable wide bandgap, impressive surface properties, mechanical strength, thermal stability, and high quantum yield, is chosen for the present work. This study aims to comprehensively investigate the structural, morphological, optical, and cytotoxic properties of zinc aluminate nano phosphors synthesized through a co-precipitation method followed by low-temperature calcination. Analysis using X-ray diffraction spectroscopy (XRD) and Fourier-transform infrared spectroscopy (FTIR) revealed that the formation of the ZnAl2O4 spinel phase initiates at 300 °C and completes at 750 °C.SEM-EDAX measurements provided further confirmation of the compositional integrity of the synthesized sample. The average crystallite size, determined to be 11.47 nm through a W-H plot, along with a higher bandgap value of 4.49 eV compared to bulk ZnAl2O4 from the diffuse reflectance spectra (DRS), attests to the success of the nanophosphor synthesis. The self-activated blue luminescent centers of ZnAl2O4 can be fine-tuned to emit light in the green and red regions of the electromagnetic spectrum through appropriate rare earth (RE) doping, utilizing Tb3+ and Eu3+ respectively. Furthermore, the particles underwent short-term in-vitro cytotoxicity testing using Dalton's Lymphoma Ascites cells (DLA) and normal cells, demonstrating high activity against DLA cells while maintaining compatibility with normal cells.

5.
Ecotoxicol Environ Saf ; 281: 116631, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38941658

RESUMO

The contamination of arsenic (As) in aqueous environments has drawn widespread attention, and iron compounds may largely alter the migration ability of As. However, the stability of As(III) in Fe-As system with the intervention of organic matter (OM) remains unclear. Herein, we had explored the co-precipitation and co-oxidation processes of As-Fe system by using batch experiments combined with Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) in this research. The precipitation quantity of As(III) increased (28.85-92.41 %) when the As/Fe ratio decreased, and increased (24.20-64.20 %) with pH increased. The main active substance for oxidizing As(III) was H2O2, which was produced in the As-Fe system. FTIR and XPS revealed that As(III) was first oxidized in neutral, and then absorbed and enteredthe interior of Fe(OH)3 colloids. But under alkaline conditions, As(III) was adsorbed by Fe (Oxyhydr) oxides firstly, and then oxidized. The intervention of OM would inhibit the redistribution process of As(III) in aqueous environments. Functional groups and unsaturation of the carbon chain were the dominant factors that affected the precipitation and oxidation processes of As(III), respectively. Co-existing ions (especially PO43-) also signally affected the precipitation quantity of As(Ⅲ) in the system and, when coexisting with OM, could exacerbate this process. The influence of co-existing ions on the redistributive process of As(III) in the As-Fe system with/without OM were as follows: PO43- > SO42- > mixed ions > SiO32-. Moreover, high concentration of OM and PO43- might lead to morphological alterations of As, acting as a threat to aqueous environments. In summary, the present findings were to further understand and appreciate the changes of As toxicity in the aqueous environments. Particularly, the coexistence of OM and As can potentially increase the risk to drinking water safety.


Assuntos
Arsênio , Ferro , Oxirredução , Poluentes Químicos da Água , Poluentes Químicos da Água/química , Arsênio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Ferro/química , Peróxido de Hidrogênio/química , Precipitação Química , Concentração de Íons de Hidrogênio , Espectroscopia Fotoeletrônica , Compostos Férricos/química , Adsorção
6.
Luminescence ; 39(2): e4693, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38403841

RESUMO

The construction of SnO2 nanoparticles (NPs), specifically Te-doped SnO2 NPs, using a simple and economical co-precipitation technique has been thoroughly described in this work. NH3 served as the reducing agent in this procedure, whilst polyethylene glycol served as the capping agent. The primary goals of our work were to investigate the physicochemical properties of the synthesized SnO2 NPs and assess their potential use as antibacterial agents and photocatalysts. Scanning electron microscopy-energy dispersive X-ray, ultraviolet light, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and other analytical techniques were used to thoroughly analyze the NPs. Based on the full width at half maximum of the most noticeable peaks in the XRD spectrum, the Debye-Scherrer equation was used to calculate the crystallite sizes, which indicated the presence of a single tetragonal SnO2 phase. Particularly noteworthy was the exceptional photocatalytic activity of graphene-assisted Te-doped SnO2 NPs, achieving an impressive decomposition efficiency of up to 98% in the photo-oxidation of methylene blue. Furthermore, our investigation delved into the antibacterial attributes of the synthesized SnO2 NPs against Escherichia coli and Staphylococcus aureus, demonstrating inhibitory effects on both bacteria strains. This suggests potential applications for these NPs in various environmental and medical contexts.


Assuntos
Nanopartículas Metálicas , Azul de Metileno , Fotólise , Azul de Metileno/química , Telúrio , Nanopartículas Metálicas/química , Antibacterianos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
7.
Luminescence ; 39(4): e4736, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38590043

RESUMO

In recent trends, radiation falls under the narrowband ultraviolet-B region (305-315 nm) widely used in phototherapy lamp applications in the treatment of skin diseases. In this paper, we report a Gd3+-doped NaYF4 luminescent material synthesized for the first time using the low-temperature co-precipitation method. It crystallized into a face-centred cubic structure, as confirmed by X-ray diffraction characterization techniques and Rietveld refinement. The photoluminescence property of the as-prepared sample shows a highly intense, sharp emission band obtained at 311 nm, which belongs to the narrowband ultraviolet-B region and corresponds to the transition of the 6P7/2→8S7/2 level of the Gd3+ ions under 272 nm excitation (8S7/2 to 6IJ). The transitions of the Gd3+ ions are detected entirely with different concentrations of Gd3+ ions. Scanning electron microscopy analysis indicated that the average particle was 288 nm. The critical distance for energy transfer was calculated to be equal to 11.5017 Å. Dipole-dipole interaction is responsible for energy transfer, as analyzed by Dexter theory. These excellent optical characteristics, together with their highly efficient and low-cost synthesis approach, indicate that synthesized NaYF4:Gd3+ phosphors have excessive potential for phototherapeutic lamp applications.


Assuntos
Luminescência , Fototerapia , Transferência de Energia , Difração de Raios X , Íons
8.
J Environ Manage ; 365: 121300, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38955041

RESUMO

Chromium contamination from abandoned industrial sites and inadequately managed waste disposal areas poses substantial environmental threat. Microbially induced carbonate precipitation (MICP) has shown promising, eco-friendly solution to remediate Cr(VI) and divalent heavy metals. In this study, MICP was carried out for chromium immobilization by an ureolytic bacterium Arthrobacter creatinolyticus which is capable of reducing Cr(VI) to less toxic Cr(III) via extracellular polymeric substances (EPS) production. The efficacy of EPS driven reduction was confirmed by cellular fraction analysis. MICP carried out in aqueous solution with 100 ppm of Cr(VI) co-precipitated 82.21% of chromium with CaCO3 and the co-precipitation is positively correlated with reduction of Cr(VI). The organism was utilized to remediate chromium spiked sand and found that MICP treatment decreased the exchangeable fraction of chromium to 0.54 ±â€¯0.11% and increased the carbonate bound fraction to 26.1 ±â€¯1.15% compared to control. XRD and SEM analysis revealed that Cr(III) produced during reduction, influenced the polymorph selection of vaterite during precipitation. Evaluation of MICP to remediate Cr polluted soil sample collected from Ranipet, Tamil Nadu also showed effective immobilization of chromium. Thus, A. creatinolyticus proves to be viable option for encapsulating chromium contaminated soil via MICP process, and effectively mitigating the infiltration of Cr(VI) into groundwater and adjacent water bodies.


Assuntos
Arthrobacter , Carbonatos , Cromo , Arthrobacter/metabolismo , Cromo/química , Carbonatos/química , Poluentes do Solo/metabolismo , Poluentes do Solo/química , Carbonato de Cálcio/química
9.
Molecules ; 29(15)2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-39124887

RESUMO

This article presents a new method for preparing multifunctional composite biomaterials with applications in advanced biomedical fields. The biomaterials consist of dicalcium phosphate (DCPD) and bioactive silicate glasses (SiO2/Na2O and SiO2/K2O), containing the antibiotic streptomycin sulfate. Materials were deeply characterized by X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopy, and zeta potential analysis, UV-visible spectrophotometry, and ion-exchange measurement were applied in a simulating body fluid (SBF) solution. The main results include an in situ chemical transformation of dicalcium phosphate into an apatitic phase under the influence of silicate solutions and the incorporation of the antibiotic. The zeta potential showed a decrease in surface charge from ζ = -24.6 mV to ζ = -16.5 mV. In addition, a controlled and prolonged release of antibiotics was observed over a period of 37 days, with a released concentration of up to 755 ppm. Toxicity tests in mice demonstrated good tolerance of the biomaterials, with no significant adverse effects. Moreover, these biomaterials have shown potent antibacterial activity against various bacterial strains, including Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, suggesting their potential use in tissue engineering, drug delivery, and orthopedic and dental implants. By integrating the antibiotic into the biomaterial composites, we achieved controlled release and prolonged antibacterial efficacy. This research contributes to advancing biomaterials by exploring innovative synthetic routes and showcasing their promise in regenerative medicine and controlled drug delivery.


Assuntos
Antibacterianos , Materiais Biocompatíveis , Medicina Regenerativa , Materiais Biocompatíveis/química , Materiais Biocompatíveis/síntese química , Medicina Regenerativa/métodos , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Animais , Camundongos , Sistemas de Liberação de Medicamentos , Difração de Raios X , Testes de Sensibilidade Microbiana , Preparações de Ação Retardada/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Fosfatos de Cálcio/química , Fosfatos de Cálcio/síntese química , Liberação Controlada de Fármacos , Estreptomicina/farmacologia , Dióxido de Silício/química
10.
Molecules ; 29(15)2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39125112

RESUMO

The physicochemical properties of natural bentonite and its sorbents were studied. It has been established the modification of natural bentonites using polyhydroxoxides of iron (III) (mod.1_Fe_5-c) and aluminum (III) (mod.1_Al_5-c) by the "co-precipitation" method led to changes in their chemical composition, structure, and sorption properties. It was shown that modified sorbents based on natural bentonite are finely porous (nanostructured) objects with a predominance of pores of 1.5-8.0 nm in size. The modification of bentonite with iron (III) and aluminum compounds by the "co-precipitation" method also leads to an increase in the sorption capacity of the obtained sorbents with respect to bichromate and arsenate anions. A kinetic analysis showed that, at the initial stage, the sorption process was controlled by an external diffusion factor, that is, the diffusion of the sorbent from the solution to the liquid film on the surface of the sorbent. The sorption process then began to proceed in a mixed diffusion mode when it limited both the external diffusion factor and the intra-diffusion factor (diffusion of the sorbent to the active centers through the system of pores and capillaries). To clarify the contribution of the chemical stage to the rate of adsorption of bichromate and arsenate anions by the sorbents under study, kinetic curves were processed using equations of chemical kinetics (pseudo-first-order, pseudo-second-order, and Elovich models). It was found that the adsorption of the studied anions by the modified sorbents based on natural bentonite was best described by a pseudo-second-order kinetic model. The high value of the correlation coefficient for the Elovich model (R2 > 0.9) allows us to conclude that there are structural disorders in the porous system of the studied sorbents, and their surfaces can be considered heterogeneous. Considering that heterogeneous processes occur on the surface of the sorbent, it is natural that all surface properties (structure, chemical composition of the surface layer, etc.) play an important role in anion adsorption.

11.
Environ Monit Assess ; 196(5): 492, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38691228

RESUMO

Bisphenol A (BPA) is an essential and extensively utilized chemical compound with significant environmental and public health risks. This review critically assesses the current water purification techniques for BPA removal, emphasizing the efficacy of adsorption technology. Within this context, we probe into the synthesis of magnetic biochar (MBC) using co-precipitation, hydrothermal carbonization, mechanical ball milling, and impregnation pyrolysis as widely applied techniques. Our analysis scrutinizes the strengths and drawbacks of these techniques, with pyrolytic temperature emerging as a critical variable influencing the physicochemical properties and performance of MBC. We explored various modification techniques including oxidation, acid and alkaline modifications, element doping, surface functional modification, nanomaterial loading, and biological alteration, to overcome the drawbacks of pristine MBC, which typically exhibits reduced adsorption performance due to its magnetic medium. These modifications enhance the physicochemical properties of MBC, enabling it to efficiently adsorb contaminants from water. MBC is efficient in the removal of BPA from water. Magnetite and maghemite iron oxides are commonly used in MBC production, with MBC demonstrating effective BPA removal fitting well with Freundlich and Langmuir models. Notably, the pseudo-second-order model accurately describes BPA removal kinetics. Key adsorption mechanisms include pore filling, electrostatic attraction, hydrophobic interactions, hydrogen bonding, π-π interactions, and electron transfer surface interactions. This review provides valuable insights into BPA removal from water using MBC and suggests future research directions for real-world water purification applications.


Assuntos
Compostos Benzidrílicos , Carvão Vegetal , Fenóis , Águas Residuárias , Poluentes Químicos da Água , Purificação da Água , Carvão Vegetal/química , Compostos Benzidrílicos/química , Compostos Benzidrílicos/análise , Fenóis/análise , Fenóis/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Águas Residuárias/química , Eliminação de Resíduos Líquidos/métodos
12.
BMC Biotechnol ; 23(1): 23, 2023 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-37474922

RESUMO

BACKGROUND: Infectious diseases prompted by micro-organisms such as fungi, parasites, or microbes, have influenced many countries' public health causing death. Scientists declared that metal oxide composites have various advantages in the medical field such as the antimicrobial feature has freshly been revealed as well as its role in suppressing mosquito population. METHODS: In this work silver doped zinc oxide nanorods (Ag/ZnO NRs, 10 wt.%) were prepared by simple chemical route, and their microstructural characteristics were investigated by XRD, EDX, SEM, and TEM techniques. The antimicrobial, larvicidal, and ovicidal of the synthesized nanocomposites were examined. RESULTS: The synthesized nanocomposite exhibited binary phase of crystallite size 112 nm was calculated from Williamson-Hall method. EDX spectrum revealed the purity of the composite consists of Zn, O, and Ag elements. The SEM and TEM micrographs showed the particles in nanorods with high density on the surface. The energy gap [Formula: see text] was evaluated from the UV-Vis absorbance in the range from 2.90 [Formula: see text] 3.08 eV inside the visible spectrum. The antimicrobial activity of the nanorods was examined against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) with inhibition zones 10.5 and 14.5 mm, respectively. Whereas gram-negative bacteria (Escherichia coli, Salmonella Typhimurium, and Pseudomonas aeruginosa) were 14 and 17 mm, respectively. Further, Candida albicans was investigated with inhibition zone 7.5 mm. Besides, the insecticidal impact of the nanocomposite against Culex pipiens larvae was performed at 30 mg/l causing 100% larval mortality with LC50 (11.78 mg/l). The micrograph images showed deformations in the larval body as well as egg resulting in zero egg hatchability. CONCLUSION: The findings approved that synthesized nanorods have a significant impact on controlling pathogens that impart different diseases to humans and the environment.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Nanotubos , Óxido de Zinco , Animais , Humanos , Antibacterianos/farmacologia , Óxido de Zinco/farmacologia , Óxido de Zinco/química , Prata/farmacologia , Prata/química , Anti-Infecciosos/farmacologia , Nanotubos/química , Íons , Nanopartículas Metálicas/química
13.
Small ; 19(32): e2301680, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37026654

RESUMO

Rare earth-doped metal oxide nanocrystals have a high potential in display, lighting, and bio-imaging, owing to their excellent emission efficiency, superior chemical, and thermal stability. However, the photoluminescence quantum yields (PLQYs) of rare earth-doped metal oxide nanocrystals have been reported to be much lower than those of the corresponding bulk phosphors, group II-VI, and halide-based perovskite quantum dots because of their poor crystallinity and high-concentration surface defects. Here, an ultrafast and room-temperature strategy for the kilogram-scale synthesis of sub-5 nm Eu3+ -doped CaMoO4 nanocrystals is presented, and this reaction can be finished in 1 min under ambient conditions. The absolute PLQYs for sub-5 nm Eu3+ -doped CaMoO4 nanocrystals can reach over 85%, which are comparable to those of the corresponding bulk phosphors prepared by the high-temperature solid state reaction. Moreover, the as-produced nanocrystals exhibit a superior thermal stability and their emission intensity unexpectedly increases after sintering at 600 °C for 2 h in air. 1.9 kg of Eu3+ -doped CaMoO4 nanocrystals with a PLQY of 85.1% can be obtained in single reaction.

14.
Photochem Photobiol Sci ; 22(1): 241-250, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36156208

RESUMO

Ce2(MoO4)3 was prepared using dielectric barrier discharge (DBD) plasma method, co-precipitation method and hydrothermal method, respectively, with water/ethanol (W/O) as solvent, oleylamine (OAm) and oleic acid (OAc) as additives. Preparation method showed significant influence on the morphological and structural properties, as well as photocatalytic performance. Ce2(MoO4)3 synthesized with DBD plasma (MO-P) was mainly flowerlike nanosheets, which were beneficial to promoting electron transfer and providing more space for catalytic activity. Also, MO-P samples exhibited more oxygen vacancies, which were conducive to the photocatalytic performance. What's more, MO-P showed lower PL intensity and narrow energy gap, which implied a slow photoelectron-hole pair recombination rate and an increased electron transfer rate. The degradation rate of methyl orange (50 mg/L) could achieve 98% within 12 min with 0.5 g/L MO-P. Hydroxyl radicals (·OH) and superoxide radicals (·O2-) played a major effect. Plasma synthesis method exhibited potential application prospect in photocatalysts preparation.


Assuntos
Aminas , Ácido Oleico , Água , Radical Hidroxila
15.
Nanotechnology ; 35(1)2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37748475

RESUMO

Highly crystalline BiFeO3(BFO), Bi0.97Sm0.03FeO3(Sm-BFO) and BiFe0.97Co0.03O3(Co-BFO) nanoparticles (NPs) were utilized as potential magnetic hyperthermia agents at two different frequencies in the radiofrequency (RF) range, and the effect of Sm3+and Co2+ion doping on the physical properties of the material was examined. The thermal behaviour of the as-prepared powders disclosed that the crystallization temperature of the powders is affected by the incorporation of the dopants into the BFO lattice and the Curie transition temperature is decreased upon doping. Vibrational analysis confirmed the formation of the R3c phase in all compounds through the characteristic FT-IR absorbance bands assigned to O-Fe-O bending vibration and Fe-O stretching of the octahedral FeO6group in the perovskite, as well as through Raman spectroscopy. The shift of the Raman-active phonon modes in Sm-BFO and Co-BFO NPs indicated structural distortion of the BFO lattice, which resulted in increased local polarization and enhanced visible light absorption. The aqueous dispersion of Co-BFO NPs showed the highest magnetic hyperthermia performance at 30 mT/765 kHz, entering the therapeutic temperature window for cancer treatment, whereas the heating efficiency of all samples was increased with increasing frequency from 375 to 765 kHz, making our doped nanoparticles to be suitable candidates for potential biomedical applications.

16.
J Fluoresc ; 2023 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-37897516

RESUMO

In our work, a novel series of europium (III) (Eu3+) (5, 10 and 15 wt %) doped cobalt tetroxide@cupric oxide (Co3O4@CuO) nanomaterials (NMs) were synthesized by facile coprecipitation method. The synthesized NMs were characterized by XRD (X-ray diffraction), FT-IR (Fourier transform infrared), UV (ultraviolet)-visible absorption spectra, XPS (X-ray photoelectron), BET (Brunauer-Emmett-Teller) analytical methods. Crystal structure studies revealed the formation of polycrystalline nature with monoclinic and cubic phase. The morphology studies of Eu3+x:Co3O4@CuO (x = 5, 10 and 15 wt %) showed petal shape nanoparticles (NPs) with agglomeration. Redshift in optical absorption spectra appeared with a significant impact on the optical band gap as Eu3+ concentration increases on Co3O4@CuO bimetallic oxide NMs. The chemical composition and valence state of the elements confirmed from XPS studies detected the presence of Eu, Cu, Co, O and C elements. An increase in the pore size and surface area resulted as the Eu3+ concentration increased on Co3O4@CuO NMs. However, room temperature photoluminescence (RTPL) spectra of Co3O4@CuO bimetallic oxide NMs at two different excitations (λ excitation = 280 nm, 320 nm) showed sharp, strong emission intensities located at near ultraviolet (NUV) region and weak emissions detected at far ultraviolet (FUV) regions of the RTPL spectrum. Further, visible range emission intensities were displayed by Eu3+:Co3O4@CuO (5, 10 and 15 wt %) NMs when exited at 280 nm. The characteristic white light emission peaks in the visible range of the RTPL spectra showed intense blue, green and orange colours. Emission intensity increases with an increase in Eu3+ concentration on Co3O4@CuO bimetallic oxide NMs. The fluorescence (FL) decay spectra of Eu3+ 10wt% and 15 wt%: Co3O4@CuO NMs showed a decay lifetime of 2.54 and 2.31 ns (ns) attributed to the dynamic, ultrafast excitation energy transfer between Eu3+ (dopant) and Co3O4@CuO (host) NMs. It is proposed that enhanced RTPL emission intensity and FL decay behavior of Eu3+x:Co3O4@CuO NMs closely related to the change in the optical band gap, variation in the crystallite size, formation of more number of oxygen vacancies in the crystal structure of hybrid nanomaterials.

17.
Environ Res ; 217: 114621, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36347396

RESUMO

The rapid industrialization of the world is disparagingly manipulating our environment and natural ecosystem. The researchers are taking keen interest to invent novel material as photocatalyst for non-degradable organic pollutants. Solar energy-driven practices employing semiconductors are a novel approach towards wastewater remediation. Here in, we successfully synthesized a vigorous photocatalysts comprising of g-C3N4 and doped ZnO-W/M (M = Co, Ce, Yb, Sm) by co-precipitation followed by metals doping via calcination approach. The structural, morphological, and photocatalytic applications for organic pollutants of synthesized heterostructure nanocomposites were examined by XRD, FTIR, SEM, EDX and UV visible spectrophotometer. Diffraction peaks attributed to both g-C3N4 and ZnO-W were detected in the XRD spectra. The FTIR spectra also inveterate the formation of g-C3N4/ZnO-W/M composites. The SEM images reveal an agglomerated morphology and EDS analysis also confirmed close contact between g-C3N4, ZnO-W and doped metals. The abridged energy band gap of g-C3N4/ZnO-W/M (M = Ce, Yb, Sm, Co) nanocomposites calculated via Tauc plot are 2.68, 2.88, 3.24 and 3.29 eV respectively. Narrowing of bandgap is considered an imperative triumph for the degradation of industrial effluents. The photocatalytic activity was performed against four different dyes and follows the trend Ce > Yb > Sm > Co. The recyclability tests were carried out for different dyes and no substantial catalytic activity loss was observed even after the fourth experimental run, which proves that reported ternary heterojunctions exhibit high mechanical stability and reusability.The species trapping experiment exposed that generated h+ are the principal active specie for dye photodegradation reactions. This work disseminates a novel photocatalyst for the removal of synthetic dyes.


Assuntos
Nanocompostos , Óxido de Zinco , Óxido de Zinco/química , Ecossistema , Catálise , Nanocompostos/química , Corantes
18.
Environ Res ; 229: 115964, 2023 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-37100363

RESUMO

Wood is an insulator material, using its porous structure to endow it with efficient microwave absorption and broaden its application range is still a major challenge. Here, wood-based Fe3O4 composites with excellent microwave absorption properties and high mechanical strength were prepared by alkaline sulfite method, in-situ co-precipitation method and compression densification method. The results showed that the magnetic Fe3O4 was densely deposited in the wood cells, and the prepared wood-based microwave absorption composites had both high electrical conductivity, magnetic loss, excellent impedance matching performance and attenuation performance, as well as effective microwave absorption properties. In the frequency range of 2-18 GHz, the minimum reflection loss value was -25.32 dB. At the same time, it had high mechanical properties. Compared with the untreated wood, its modulus of elasticity (MOE) in bending increased by 98.77%, and modulus of rapture (MOR) in bending improved by 67.9%. The developed wood-based microwave absorption composite is expected to be used in electromagnetic shielding fields such as anti-radiation and anti-interference.


Assuntos
Óxido Ferroso-Férrico , Madeira , Campos Eletromagnéticos , Micro-Ondas , Porosidade
19.
Environ Res ; 220: 115272, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36634893

RESUMO

The conversion of agricultural waste into high-value carbon products has been an attractive area in waste management strategy. This study highlighted the synthesis and effectiveness of green pea peels (GPP), green pea biochar (GPBC), and nano-ferromagnetic green pea biochar (NFGPBC) by the ferrous/ferric co-precipitation synthesis method for eliminating cationic dyes molecules from solutions. The morphological, physicochemical, and structural properties of GPP, GPBC, and NFGPBC were approved by Scanning Electron Microscopy (SEM), Transmission Emission Microscopy (TEM), Energy Dispersive X-ray (EDX), Bruneau Emmett Teller (BET), Fourier Transform Infrared spectroscopy (FTIR), and X-ray Diffraction (XRD) techniques. Vibrating Sample Magnetometry (VSM) analysis confirmed the NFGPBC magnetization performance. The capacity of each adsorbent for methylene blue removal was evaluated at various parameters of material dosage (50-250 mg/150 mL), pH (2-12), initial concentration (50-250 mg/L), contact time (0-90 min) and temperature (20-60 °C). The three developed adsorbent materials GPP, GPBC, and NFGPBC, possessed reasonable BET surface areas of 0.6836, 372.54, and 147.88 m2g-1, and the corresponding monolayer adsorption capacities of 163.93, 217.40, and 175.44 mg/g, respectively. The superior performances of GPBC and NFGPBC were due to their increased surface area compared with the parent green pea peels (GPP). The results from adsorption kinetics studies of all prepared materials were pseudo-second-order and Elovich kinetics models. The thermodynamic parameters exhibited MB sorption's favorability, spontaneity, and endothermic nature. The NFGPBC material experienced Vander Waal forces, electrostatic interaction, hydrogen bonding, and hydrophobic interactions as predominant modes of the solid-liquid interaction. The regeneration, recycling, and reusability of the synthesized GPP, GPBC, and NFGPBC performed at five adsorption cycles revealed that NFGPBC demonstrated excellent cyclical performances attaining a minimum 8.9% loss in capacity due to paramagnetic properties. Thus, NFGPBC is a green, efficient, and eco-friendly material recommended for large-scale production and application in wastewater.


Assuntos
Azul de Metileno , Poluentes Químicos da Água , Pisum sativum , Descontaminação , Carvão Vegetal/química , Adsorção , Cinética , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Int J Mol Sci ; 24(16)2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37629040

RESUMO

Zinc ferrite nanoparticles (ZFO NPs) are a promising magneto-crystalline platform for nanomedicine-based cancer theranostics. ZFO NPs synthesized using co-precipitation method are characterized using different techniques. UV-visible spectroscopy exhibits absorption peaks specific for ZFO. Raman spectroscopy identifies Raman active, infrared active, and silent vibrational modes while Fourier transforms infrared spectroscopic (FTIR) spectra display IR active modes that confirm the presence of ZFO. X-ray diffraction pattern (XRD) exhibits the crystalline planes of single-phase ZFO with a face-centered cubic structure that coincides with the selected area electron diffraction pattern (SAED). The average particle size according to high-resolution transmission electron microscopy (HR-TEM) is 5.6 nm. X-ray photoelectron spectroscopy (XPS) signals confirm the chemical states of Fe, Zn, and O. A superconducting quantum interference device (SQUID) displays the magnetic response of ZFO NPs, showing a magnetic moment of 45.5 emu/gm at 70 kOe. These ZFO NPs were then employed for comparative cytotoxicity evaluation using MTT, crystal violet, and LDH assays on breast adenocarcinoma epithelial cell (MCF-7), triple-negative breast cancer lines (MDA-MB 231), and human embryonic kidney cell lines (HEK-293). Flow cytometric analysis of all the three cell lines were performed in various concentrations of ZFO NPs for automated cell counting and sorting based on live cells, cells entering in early or late apoptotic phase, as well as in the necrotic phase. This analysis confirmed that ZFO NPs are more cytotoxic towards triple-negative breast cancer cells (MDA-MB-231) as compared to breast adenocarcinoma cells (MCF-7) and normal cell lines (HEK-293), thus corroborating that ZFO can be exploited for cancer therapeutics.


Assuntos
Adenocarcinoma , Antineoplásicos , Neoplasias de Mama Triplo Negativas , Humanos , Violeta Genciana , Zinco , Células HEK293 , Apoptose
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