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1.
J Chem Phys ; 161(10)2024 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-39248239

RESUMO

Carbonyl groups (C=O) play crucial roles in the photophysics and photochemistry of biological systems. O1s x-ray photoelectron spectroscopy allows for targeted investigation of the C=O group, and the coupling between C=O vibration and O1s ionization is reflected in the fine structures. To elucidate its characteristic vibronic features, systematic Franck-Condon simulations were conducted for six common biomolecules, including three purines (xanthine, caffeine, and hypoxanthine) and three pyrimidines (thymine, 5F-uracil, and uracil). The complexity of simulation for these biomolecules lies in accounting for temperature effects and potential tautomeric variations. We combined the time-dependent and time-independent methods to efficiently account for the temperature effects and to provide explicit assignments, respectively. For hypoxanthine, the tautomeric effect was considered by incorporating the Boltzmann population ratios of two tautomers. The simulations demonstrated good agreement with experimental spectra, enabling differentiation of two types of carbonyl oxygens with subtle local structural differences, positioned between two nitrogens (O1) or between one carbon and one nitrogen (O2). The analysis provided insights into the coupling between C=O vibration and O1s ionization, consistently showing an elongation of the C=O bond length (by 0.08-0.09 Å) upon O1s ionization.


Assuntos
Espectroscopia Fotoeletrônica , Temperatura , Vibração , Pirimidinas/química , Purinas/química
2.
Biointerphases ; 19(5)2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39235276

RESUMO

In order to properly satisfy biomedical constraints for cardiovascular applications, additively manufactured NiTi scaffolds required further process and metallurgical engineering. Additively manufactured NiTi materials for cardiovascular use will have to undergo surface finishing in order to minimize negative surface interactions within the artery. In this study, we sought to understand biocompatibility from chemically etched additively manufactured NiTi scaffolds by laser powder bed fusion (LPBF). Although two distinct oxide films were created in the surface etching process (labeled CP-A and CP-B), no qualitative changes in microroughness were seen between the two conditions. CP-A possessed significantly less Ni at the surface (0.19 at. %) than the CP-B group (3.30 at. %), via x-ray photoelectron spectroscopy, alongside a concomitant shift in the O1 s peak presentation alluding to a greater formation of a Ni based oxide in the CP-B group. Our live dead staining revealed significant toxicity and reduced cellular attachment for the CP-B group, in addition to inducing more cell lysis (20.9 ± 5.1%), which was significantly increased when compared to CP-A (P < 0.01). Future practices of manufacturing NiTi scaffolds using LPBF should focus on producing surface films that are not only smooth, but free of cytotoxic Ni based oxides.


Assuntos
Materiais Biocompatíveis , Níquel , Propriedades de Superfície , Titânio , Titânio/química , Titânio/farmacologia , Níquel/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Humanos , Óxidos/química , Óxidos/farmacologia , Teste de Materiais , Sobrevivência Celular/efeitos dos fármacos , Espectroscopia Fotoeletrônica , Adesão Celular/efeitos dos fármacos , Alicerces Teciduais/química
3.
Int J Mol Sci ; 25(16)2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39201510

RESUMO

This study aims to improve the photocatalytic properties of titanium dioxide nanorods (TNRs) and other related nanostructures (dense nanorods, needle-like nanorods, nanoballs, and nanoflowers) by modifying them with silver nanoparticles (AgNPs). This preparation is carried out using a two-step method: sol-gel dip-coating deposition combined with hydrothermal crystal growth. Further modification with AgNPs was achieved through the photoreduction of Ag+ ions under UV illumination. The investigation explores the impact of different growth factors on the morphological development of TiO2 nanostructures by modulating (i) the chemical composition, the water:acid ratio, (ii) the precursor concentration involved in the hydrothermal process, and (iii) the duration of the hydrothermal reaction. Morphological characteristics, including the length, diameter, and nanorod density of the nanostructures, were analyzed using scanning electron microscope (SEM). The chemical states were determined through use of the X-ray photoelectron spectroscopy (XPS) technique, while phase composition and crystalline structure analysis was performed using the Grazing Incidence X-ray Diffraction (GIXRD) method. The results indicate that various nanostructures (dense nanorods, needle-like nanorods, nanoballs, and nanoflowers) can be obtained by modifying these parameters. The photocatalytic efficiency of these nanostructures and Ag-coated nanostructures was assessed by measuring the degradation of the organic dye rhodamine B (RhB) under both ultraviolet (UV) irradiation and visible light. The results clearly show that UV light causes the RhB solution to lose its color, whereas under visible light RhB changes into rhodamine 110, indicating a successful photocatalytic transformation. The nanoball-like structures' modification with the active metal silver (TNRs 4 Ag) exhibited high photocatalytic efficiency under both ultraviolet (UV) and visible light for different chemical composition parameters. The nanorod structure (TNRs 2 Ag) is more efficient under UV, but under visible-light photocatalyst, the TNRs 6 Ag (dense nanorods) sample is more effective.


Assuntos
Nanopartículas Metálicas , Prata , Titânio , Titânio/química , Prata/química , Nanopartículas Metálicas/química , Catálise , Nanoestruturas/química , Rodaminas/química , Processos Fotoquímicos , Nanotubos/química , Raios Ultravioleta , Fotólise , Difração de Raios X , Espectroscopia Fotoeletrônica
4.
Arch Oral Biol ; 167: 106062, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39094423

RESUMO

OBJECTIVE: Alveolar bone quality is essential for the maxillofacial integrity and function, and depends on alveolar bone mineralization. This study aims to investigate the in vivo changes in alveolar bone mineralization, from the perspective of mineral deposition and crystal transition in postnatal rats. DESIGN: Nine postnatal time points of Wistar rats, ranging from day 1 to 56, were set to obtain the maxillary alveolar bone samples. Each time point consisted of ninety rats, with 45 females and 45 males. Macromorphology of alveolar bone was reconducted by Micro-Computed Tomography and the mineral content was quantified via Thermogravimetric analysis, Scanning Electron Microscope, High-Resolution Transmission Electron Microscopy and vibrational spectroscopy. Furthermore, the crystallinity and composition were characterized by vibrational spectroscopy, X-ray Diffraction, X-ray Photoelectron Spectroscopy and Selected Area Electron Diffraction. RESULTS: The progressive increase of mineral deposition was accompanied by substantial growth in alveolar bone mass and volume in postnatal rats. Whereas the mineral percentage initially decreased and then increased, reaching a nadir on postnatal day 14 (P14) when tooth eruption was first observed. Besides, localized mineralization was initiated by the formation of amorphous precursors and then converted into mineral crystals, while there was no statistically significant change in the average crystallinity of the bone during growth. CONCLUSION: Mineralization of alveolar bone is ongoing throughout the early growth in postnatal rats. Mineral deposition increases with age, whereas the crystallinity remains stable within a certain range. Besides, the mineral percentage reaches its lowest point on P14, which may be attributed to tooth eruption.


Assuntos
Processo Alveolar , Calcificação Fisiológica , Microscopia Eletrônica de Varredura , Ratos Wistar , Microtomografia por Raio-X , Animais , Ratos , Feminino , Masculino , Calcificação Fisiológica/fisiologia , Processo Alveolar/crescimento & desenvolvimento , Processo Alveolar/diagnóstico por imagem , Processo Alveolar/metabolismo , Difração de Raios X , Microscopia Eletrônica de Transmissão , Termogravimetria , Densidade Óssea , Espectroscopia Fotoeletrônica , Maxila/crescimento & desenvolvimento
5.
Int J Biol Macromol ; 278(Pt 1): 134500, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39128765

RESUMO

The rich active hydroxyl groups on starch nanocrystals (SNC) surface limits its dispersion and stability in the aqueous phase. To address this issue, ozone modification for 0 (SNC), 0.5 (SNC-1), 1 (SNC-2), 1.5 (SNC-3), and 2 h (SNC-4) as compared to conventionally chemical methods was applied to functionally modify the SNC. The impact of ozone treatment on the structural and surface characteristics of waxy rice starch nanocrystals. The findings revealed that longer ozone treatment durations favored the formation of carbonyl groups in starch molecules. Initially, ozone oxidized the hydroxyl group of the macromolecule. Once the carbonyl groups formed, the cross-linking reaction occurred among starch nanocrystals through condensation reactions, leading to the increasing molecular orderliness. X-ray photoelectron spectroscopy, X-ray diffraction and Small-angle X-ray scattering analyses of SNC-2 supported this finding with a reduced O/C ratio, and implied that surface oxidation did not alter the crystal type but rather enhanced molecular hydration in an aqueous system, leading to increased interfacial thickness and fractal dimension. Additionally, ozone oxidation improved surface properties such as charge and hydrophobicity. Oxidized SNC also exhibited altered gelatinization properties due to surface degradation. This study offers a promising strategy for enhancing SNC surface properties, crucial for food science applications.


Assuntos
Nanopartículas , Oryza , Ozônio , Amido , Propriedades de Superfície , Ozônio/química , Amido/química , Oryza/química , Nanopartículas/química , Oxirredução , Difração de Raios X , Interações Hidrofóbicas e Hidrofílicas , Espectroscopia Fotoeletrônica
6.
Water Res ; 265: 122320, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39197392

RESUMO

The efficient capture of uranium from wastewater is crucial for environmental remediation and the sustainable development of nuclear energy, yet it poses considerable challenges. In this study, amphiphilic ionic covalent organic framework intercalated into graphene oxide (GO) nanosheets functionalized with polyethyleneimine (PEI) were used to construct hybrid membranes with ultrafast uranium adsorption. These hybrid membranes achieved equilibrium in just 10 min and the adsorption capacity was as high as 358.8 mg g-1 at pH = 6. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses revealed that the strong interaction between sulfonic acid groups and uranyl ions was the primary reason for the high adsorption capacity and selectivity. The extended transition state and natural orbitals for chemical valence (ETS-NOCV) analysis revealed that the interaction between the 7 s and 5f orbitals of uranyl and the 2p orbitals of S and O in the sulfonate was the primary reason for the strong interaction between the sulfonate and the uranyl ion. This research presents an effective method for the rapid extraction of uranium from wastewater.


Assuntos
Grafite , Urânio , Águas Residuárias , Urânio/química , Grafite/química , Águas Residuárias/química , Adsorção , Espectroscopia Fotoeletrônica , Membranas Artificiais , Estruturas Metalorgânicas/química , Poluentes Radioativos da Água/química
7.
Biosens Bioelectron ; 263: 116599, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39111251

RESUMO

Surface biofunctionalization is an essential stage in the preparation of any bioassay affecting its analytical performance. However, a complete characterization of the biofunctionalized surface, considering studies of coverage density, distribution and orientation of biomolecules, layer thickness, and target biorecognition efficiency, is not met most of the time. This review is a critical overview of the main techniques and strategies used for characterizing biofunctionalized surfaces and the process in between. Emphasis is given to scanning force microscopies as the most versatile and suitable tools to evaluate the quality of the biofunctionalized surfaces in real-time dynamic experiments, highlighting the helpful of atomic force microscopy, Kelvin probe force microscopy, electrochemical atomic force microscopy and photo-induced force microscopy. Other techniques such as optical and electronic microscopies, quartz crystal microbalance, X-ray photoelectron spectroscopy, contact angle, and electrochemical techniques, are also discussed regarding their advantages and disadvantages in addressing the whole characterization of the biomodified surface. Scarce reviews point out the importance of practicing an entire characterization of the biofunctionalized surfaces. This is the first review that embraces this topic discussing a wide variety of characterization tools applied in any bioanalysis platform developed to detect both clinical and environmental analytes. This survey provides information to the analysts on the applications, strengths, and weaknesses of the techniques discussed here to extract fruitful insights from them. The aim is to prompt and help the analysts to accomplish an entire assessment of the biofunctionalized surface, and profit from the information obtained to enhance the bioanalysis output.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Microscopia de Força Atômica , Técnicas de Microbalança de Cristal de Quartzo , Propriedades de Superfície , Técnicas Biossensoriais/métodos , Humanos , Técnicas Eletroquímicas/métodos , Técnicas de Microbalança de Cristal de Quartzo/métodos , Espectroscopia Fotoeletrônica , Animais
8.
ACS Sens ; 9(8): 4079-4088, 2024 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-39057835

RESUMO

Ambient pressure X-ray photoelectron spectroscopy (APXPS) is combined with simultaneous electrical measurements and supported by density functional theory calculations to investigate the sensing mechanism of tungsten disulfide (WS2)-based gas sensors in an operando dynamic experiment. This approach allows for the direct correlation between changes in the surface potential and the resistivity of the WS2 sensing active layer under realistic operating conditions. Focusing on the toxic gases NO2 and NH3, we concurrently demonstrate the distinct chemical interactions between oxidizing or reducing agents and the WS2 active layer and their effect on the sensor response. The experimental setup mimics standard electrical measurements on chemiresistors, exposing the sample to dry air and introducing the target gas analyte at different concentrations. This methodology applied to NH3 concentrations of 100, 230, and 760 and 14 ppm of NO2 establishes a benchmark for future APXPS studies on sensing devices, providing fast acquisition times and a 1:1 correlation between electrical response and spectroscopy data in operando conditions. Our findings contribute to a deeper understanding of the sensing mechanism in 2D transition metal dichalcogenides, paving the way for optimizing chemiresistor sensors for various industrial applications and wireless platforms with low energy consumption.


Assuntos
Amônia , Espectroscopia Fotoeletrônica , Amônia/análise , Amônia/química , Dióxido de Nitrogênio/análise , Dióxido de Nitrogênio/química , Compostos de Tungstênio/química , Teoria da Densidade Funcional , Pressão , Gases/análise , Gases/química , Tungstênio/química
9.
Environ Sci Pollut Res Int ; 31(36): 49172-49184, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39052116

RESUMO

As a most promising environmental technology, the substantial enhancement of photocatalytic efficiency is still a big challenge for practical applications. In this work, the surface of Bi2O2CO3 (BOC) nanotubes are modified by Cl and I. The as-obtained samples at different hydrothermal temperatures (T) are designated as T-X-BOC (X = Cl, I). X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS) prove that Cl and I merely chemically adsorb on the BOC surface, rather than dope into the crystal lattice. The surface modification of Cl and I slightly increases light absorption range, while significantly promotes the photoelectron migration from bulk to the surface that greatly enhances the carrier separation efficiency. Density functional theory (DFT) calculations further prove that surface Cl and I have adjusted band structure and surface charge distribution. Besides, the surface Cl and I favor the O2 adsorption and trap the surface photoelectrons, thus promoting the formation of •O2-; while the surface Cl and I impede the surface adsorption of H2O, thus refraining the generation of •OH. In the degradation of rhodamine B (RhB), holes and •O2- radicals play the crucial role. Under ultraviolet light irradiation (λ < 420 nm) for 45 min, the RhB degradation ratios over 150-Cl-BOC (94%) and 150-I-BOC (85%) are 4.2 and 3.7 times higher than that of original BOC (18%), respectively. This work demonstrates that the simple surface halogenation modification greatly improves the photocatalytic activity.


Assuntos
Oxigênio , Adsorção , Oxigênio/química , Espectroscopia Fotoeletrônica , Propriedades de Superfície , Íons/química , Rodaminas/química
10.
Adv Sci (Weinh) ; 11(32): e2405942, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38958529

RESUMO

A novel Fe2Mo3O8/MoO2@MoS2 nanocomposite is synthesized for extremely sensitive detection of NH3 in the breath of kidney disease patients at room temperature. Compared to MoS2, α-Fe2O3/MoS2, and MoO2@MoS2, it shows the optimal gas-sensing performance by optimizing the formation of Fe2Mo3O8 at 900 °C. The annealed Fe2Mo3O8/MoO2@MoS2 nanocomposite (Fe2Mo3O8/MoO2@MoS2-900 °C) sensor demonstrates a remarkably high selectivity of NH3 with a response of 875% to 30 ppm NH3 and an ultralow detection limit of 3.7 ppb. This sensor demonstrates excellent linearity, repeatability, and long-term stability. Furthermore, it effectively differentiates between patients at varying stages of kidney disease through quantitative NH3 measurements. The sensing mechanism is elucidated through the analysis of alterations in X-ray photoelectron spectroscopy (XPS) signals, which is supported by density functional theory (DFT) calculations illustrating the NH3 adsorption and oxidation pathways and their effects on charge transfer, resulting in the conductivity change as the sensing signal. The excellent performance is mainly attributed to the heterojunction among MoS2, MoO2, and Fe2Mo3O8 and the exceptional adsorption and catalytic activity of Fe2Mo3O8/MoO2@MoS2-900 °C for NH3. This research presents a promising new material optimized for detecting NH3 in exhaled breath and a new strategy for the early diagnosis and management of kidney disease.


Assuntos
Amônia , Testes Respiratórios , Dissulfetos , Molibdênio , Nanocompostos , Nanocompostos/química , Amônia/análise , Humanos , Molibdênio/química , Testes Respiratórios/métodos , Testes Respiratórios/instrumentação , Dissulfetos/química , Nefropatias/diagnóstico , Temperatura , Espectroscopia Fotoeletrônica/métodos , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/instrumentação
11.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 42(4): 452-461, 2024 Aug 01.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-39049632

RESUMO

OBJECTIVES: The aim of this study was to evaluate the effects of collagen modification on the osteogenic performance of different surface-modified titanium, including alkaline etching, alkaline etching followed by silanization, and alkaline etching followed by dopamine modification. The proliferation, adhesion, and osteogenic differentiation abilities of MC3T3-E1 cells on the surfaces with collagen modification were analyzed and compared. METHODS: Collagen was immobilized on the surfaces of pure titanium (Ti-C), alkaline-etched titanium (Ti-Na-C), alkaline-etched and silanized titanium (Ti-A-C), and alkaline-etched and dopamine-modified titanium (Ti-D-C), with pure titanium (Ti) as the control group. The surface morphology was observed by scanning electron microscopy (SEM), and the surface elemental composition was analyzed by X-ray photoelectron spectroscopy (XPS). Contact angle measurements were conducted to evaluate the hydrophilicity of the surfaces. MC3T3-E1 cells were cultured on the surfaces, and their proliferation, adhesion, and osteogenic differentiation abilities were assessed using CCK-8 assay, laser scanning confocal microscope, alkaline phosphatase (ALP) staining, Alizarin red staining and quantitative analysis, as well as real-time quantitative polymerase chain reaction (RT-qPCR) to evaluate the mRNA expression levels of osteogenic-related genes, including ALP, typeⅠcollagen (COL-1), osteocalcin (OCN), osteopontin (OPN). RESULTS: SEM and XPS results confirmed the successful immobilization of collagen on the titanium surfaces, with the Ti-Na-C group exhibiting a higher amount of collagen modification. Contact angle measurements showed improved hydrophilicity of the surfaces after collagen modification. CCK-8 results indicated good compatibility of the materials with MC3T3-E1, with enhanced cell proliferation on the collagen-modified surfaces. Cell fluorescence staining revealed better cell spreading on the collagen-modified surfaces, and ALP and Alizarin red staining results suggested that the Ti-Na-C group exhibited the best osteogenic performance, with significantly higher absorbance values in the Alizarin red quantification analysis. RT-qPCR analysis showed that the Ti-Na-C group had the highest expression of the osteogenic-related gene OPN. CONCLUSIONS: Among the different collagen modification approaches employed in this study, collagen modification on alkaline-etched titanium surfaces showed the most conducive effects on MC3T3-E1 cell adhesion, spreading, proliferation, and osteogenic differentiation. This approach can be considered as the optimal collagen modification strategy for enhancing osteogenesis on titanium surfaces.


Assuntos
Diferenciação Celular , Proliferação de Células , Colágeno , Osteoblastos , Osteogênese , Propriedades de Superfície , Titânio , Titânio/química , Animais , Camundongos , Adesão Celular , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Fosfatase Alcalina/metabolismo , Osteocalcina/metabolismo
12.
Sci Rep ; 14(1): 16112, 2024 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-38997319

RESUMO

In the present work, Verbena Officinalis (VO) leaf extract was used as potential corrosion inhibitor for the corrosion of carbon steel (CS) in 0.5 M H2SO4 medium. Further, the corrosion inhibiting nature of VO leaf extract towards the CS was evaluated using mass loss (ML), potentiodynamic polarization (PDP), electrical impedance spectroscopy (EIS) and surface morphological analyses using atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) techniques. Calculation of activation energy E a ∗ using Arrhenius equation shows the increase in activation energy when adding the VO leaf extract in 0.5 M H2SO4 medium and the maximum activation energy ( E a ∗ = 49.9 kJ mol-1) was observed for 1000 mg L-1 VO leaf extract in acid medium. The negative free energy values suggested the spontaneous and the stability of the adsorbed layer of VO leaf extract on the CS surface. Using EIS measurements, high percent inhibitory effectiveness of 91.1% for 1000 ppm solutions was achieved. With an increase in VO leaf extract dose, the double layer capacitance (Cdl) values fall while the values of charge transfer (Rct) increase. This showed that a protective layer of VO leaf extract on CS surface was formed. The polarization curves showed that the VO leaf extract acts as a mixed-type inhibitor. It is discovered that the adsorption of VO leaf extract molecules adhering to the CS surface followed the Langmuir isotherm. The anti-corrosion action of VO leaf extract is fully demonstrated by some surface techniques.


Assuntos
Extratos Vegetais , Folhas de Planta , Aço , Verbena , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Aço/química , Corrosão , Verbena/química , Microscopia de Força Atômica , Espectroscopia Fotoeletrônica , Carbono/química , Concentração de Íons de Hidrogênio , Propriedades de Superfície , Espectroscopia Dielétrica
13.
Int J Mol Sci ; 25(13)2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-39000062

RESUMO

The present work focuses on the synthesis of a vanadium nitride (VN)/carbon nanocomposite material via the thermal decomposition of vanadyl phthalocyanine (VOPC). The morphology and chemical structure of the synthesized compounds were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoemission spectroscopy (XPS). The successful syntheses of the VOPC and non-metalated phthalocyanine (H2PC) precursors were confirmed using FTIR and XRD. The VN particles present a needle-like morphology in the VN synthesized by the sol-gel method. The morphology of the VN/C composite material exhibited small clusters of VN particles. The XRD analysis of the thermally decomposed VOPC indicated a mixture of amorphous carbon and VN nanoparticles (VN(TD)) with a cubic structure in the space group FM-3M consistent with that of VN. The XPS results confirmed the presence of V(III)-N bonds in the resultant material, indicating the formation of a VN/C nanocomposite. The VN/C nanocomposite synthesized through thermal decomposition exhibited a high carbon content and a cluster-like distribution of VN particles. The VN/C nanocomposite was used as an anode material in LIBs, which delivered a specific capacity of 307 mAh g-1 after 100 cycles and an excellent Coulombic efficiency of 99.8 at the 100th cycle.


Assuntos
Carbono , Nanocompostos , Nanocompostos/química , Carbono/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Indóis/química , Vanádio/química , Compostos de Vanádio/química , Espectroscopia Fotoeletrônica
14.
Chemosphere ; 362: 142864, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39019184

RESUMO

Effective removal of phosphate from water is essential for preventing the eutrophication and worsening of water quality. This study aims to enhance phosphate removal by synthesizing starch-stabilized ferromanganese binary oxide (FMBO-S), discover the factors, and investigate adsorption mechanisms. FMBO and FMBO-S properties were studied using Scanning Electron Microscopy, BET analysis, Polydispersity Index (PDI), Fourier Transform Infrared Spectroscopy, and X-ray Photoelectron Spectroscopy (XPS). After starch loading, the average pore diameter increased from 14.89 Å to 25.16 Å, and significantly increased the pore volume in the mesopore region. FMBO-S showed a PDI value below 0.5 indicating homogeneous size dispersity and demonstrated faster and higher adsorption capacity: 61.24 mg g-1 > 28.57 mg g-1. Both FMBO and FMBO-S adsorption data fit well with the pseudo-second-order and Freundlich models, indicating a chemisorption and multilayered adsorption process. The phosphate adsorption by FMBO was pH-dependent, suggesting electrostatic attraction as the dominant mechanism. For the FMBO-S, phosphate adsorption was favored in a wide pH range, despite the weaker electrostatic attraction as evident from the point of zero charge and zeta potential values, indicating ligand exchange as a main mechanism. Moreover, the XPS analysis shows a significant change in the proportion of Fe species for FMBO-S than FMBO after phosphate adsorption, indicating significant involvement of Fe. Meanwhile, phosphate adsorption was almost unaffected by the presence of Cl-, NO3-, and SO42- anions, whereas CO32- significantly reduced the adsorption capacity. This study revealed that FMBO-S could be a promising, low-cost adsorbent for phosphate removal and recovery from water.


Assuntos
Óxidos , Fosfatos , Amido , Poluentes Químicos da Água , Purificação da Água , Adsorção , Amido/química , Fosfatos/química , Poluentes Químicos da Água/química , Óxidos/química , Purificação da Água/métodos , Espectroscopia Fotoeletrônica , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Bioresour Technol ; 407: 131124, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39025370

RESUMO

In this study, magnetic biochar was synthesized by doping Fe3O4 onto the biochar surface followed by analysis of its properties. The efficiency of methylene blue (MB) removal through the combined processes of adsorption and photolysis was assessed. The presence of Fe3O4 on the biochar surface was confirmed using Raman spectroscopy and X-ray photoelectron spectroscopy. The magnetic biochar, after MB adsorption, showed a magnetism of 39.50 emu/g leading to a 97.07 % recovery rate. The specific surface area of biochar was higher (380.68 m2/g) than that of magnetic biochar (234.46 m2/g), and the maximum adsorption capacity of MB was higher in the biochar (0.03 mg/g) than that in magnetic biochar (0.02 mg/g) under the optimal conditions for MB adsorption. The MB adsorption experiments using biochar or magnetic biochar were optimally conducted under 10-20 mg/L MB concentration, 1 g biochar dosage, pH 12, 200 rpm rotation speed, 25 °C temperature, and 30 min duration. Under dark conditions, biochar had a higher MB removal rate, at 83.91 %, compared to magnetic biochar, at 78.30 %. Under visible light (λ > 425 nm), magnetic biochar effectively removed MB within 10 min, highlighting the synergistic effect of adsorption and photolysis. MB is physically and chemically adsorbed by the monolayer on the surface of EB and EMB according to adsorption behavior.


Assuntos
Carvão Vegetal , Lignina , Azul de Metileno , Fotólise , Azul de Metileno/química , Carvão Vegetal/química , Adsorção , Lignina/química , Biomassa , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/química , Espectroscopia Fotoeletrônica
16.
Int J Mol Sci ; 25(13)2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38999979

RESUMO

This study presents a pioneering synthesis of a direct Z-scheme Y2TmSbO7/GdYBiNbO7 heterojunction photocatalyst (YGHP) using an ultrasound-assisted hydrothermal synthesis technique. Additionally, novel photocatalytic nanomaterials, namely Y2TmSbO7 and GdYBiNbO7, were fabricated via the hydrothermal fabrication technique. A comprehensive range of characterization techniques, including X-ray diffractometry, Fourier-transform infrared spectroscopy, Raman spectroscopy, UV-visible spectrophotometry, X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray energy-dispersive spectroscopy, fluorescence spectroscopy, photocurrent testing, electrochemical impedance spectroscopy, ultraviolet photoelectron spectroscopy, and electron paramagnetic resonance, was employed to thoroughly investigate the morphological features, composition, chemical, optical, and photoelectric properties of the fabricated samples. The photocatalytic performance of YGHP was assessed in the degradation of the pesticide acetochlor (AC) and the mineralization of total organic carbon (TOC) under visible light exposure, demonstrating eximious removal efficiencies. Specifically, AC and TOC exhibited removal rates of 99.75% and 97.90%, respectively. Comparative analysis revealed that YGHP showcased significantly higher removal efficiencies for AC compared to the Y2TmSbO7, GdYBiNbO7, or N-doped TiO2 photocatalyst, with removal rates being 1.12 times, 1.21 times, or 3.07 times higher, respectively. Similarly, YGHP demonstrated substantially higher removal efficiencies for TOC than the aforementioned photocatalysts, with removal rates 1.15 times, 1.28 times, or 3.51 times higher, respectively. These improvements could be attributed to the Z-scheme charge transfer configuration, which preserved the preferable redox capacities of Y2TmSbO7 and GdYBiNbO7. Furthermore, the stability and durability of YGHP were confirmed, affirming its potential for practical applications. Trapping experiments and electron spin resonance analyses identified active species generated by YGHP, namely •OH, •O2-, and h+, allowing for comprehensive analysis of the degradation mechanisms and pathways of AC. Overall, this investigation advances the development of efficient Z-scheme heterostructural materials and provides valuable insights into formulating sustainable remediation strategies for combatting AC contamination.


Assuntos
Luz , Toluidinas , Catálise , Toluidinas/química , Fotólise , Poluentes Químicos da Água/química , Processos Fotoquímicos , Espectroscopia Fotoeletrônica , Gadolínio/química
17.
J Dent Res ; 103(8): 820-829, 2024 07.
Artigo em Inglês | MEDLINE | ID: mdl-38867655

RESUMO

The water-rich nature of the dentin bonding microenvironment, coupled with the stresses on the bonding interface, contributes to the hydrolytic degradation of the hybrid layer, resulting in a decline in bonding durability and, ultimately, restoration failure. Currently, the 3-step etch-and-rinse technique remains the gold standard for dentin bonding, and the bonding mechanism mainly involves a physical interaction with little chemical bonding. In this study, we have developed a siloxane-modified polyurethane monomer (SPU) with acrylate and siloxane modifications that chemically binds to both collagen and hydroxyapatite in dentin. Formulated as a bisphenol A-glycidyl methacrylate alternative, the SPU monomer-based adhesive was designed to improve dentin bonding quality and durability. Attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscope, and hydroxyproline release assays were performed on SPU-treated collagen, hydroxyapatite, and acid-etched dentin slices to dentin. The physicochemical properties of the configured SPU adhesives were profiled for polymerization behavior, water contact angle, and tensile strain and strength. The bonding effectiveness was assessed through micro-tensile strength, nano-leakage tests conducted on the bonded samples before and after thermal cycle aging. Finally, we further conducted in vivo and in vitro experiments to assess the biocompatibility of adhesives. The results showed that the siloxane groups of SPU monomer could covalently bind to dentin collagen and hydroxyapatite. The incorporation of SPU in the adhesive led to a significant increase in adhesive polymerization (P < 0.05) and tensile strain at break up to 134.11%. Furthermore, the SPU adhesive significantly improved dentin bond strength (P < 0.05), reduced interfacial nano-leakage (P < 0.05), and displayed good biocompatibility. In conclusion, the application of SPU, which achieves dual chemical bonding with dentin, can improve the quality of the hybrid layer, buffer the interfacial stresses, enhance the interfacial resistance to hydrolysis, and provide a feasible strategy to extend the service life of adhesive restorations.


Assuntos
Colagem Dentária , Adesivos Dentinários , Dentina , Teste de Materiais , Microscopia Eletrônica de Varredura , Resistência à Tração , Dentina/química , Colagem Dentária/métodos , Adesivos Dentinários/química , Humanos , Espectroscopia de Infravermelho com Transformada de Fourier , Durapatita/química , Poliuretanos/química , Colágeno/química , Colágeno/metabolismo , Siloxanas/química , Espectroscopia Fotoeletrônica , Propriedades de Superfície , Termogravimetria , Microscopia Eletrônica de Transmissão , Bis-Fenol A-Glicidil Metacrilato/química , Condicionamento Ácido do Dente , Polimerização
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 321: 124720, 2024 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-38943756

RESUMO

Copper oxide nanosheets (CuO NSs) have been successfully obtained by exploiting an effective one-step approach of sugar-blowing method followed by calcination. The nanosheets were characterized by several techniques like X-ray powder diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Impressively, CuO NSs display haloperoxidase (HPO) like catalytic activity which catalyses the oxidation of chloride ions by H2O2 giving rise to reactive chlorine species (RCS). A sensitive and selective colorimetric sensor was then demonstrated via the oxidation of chromogenic substrate 3,3',5,5'- tetramethylbenzidine (TMB) by the novel nanoenzyme CuO NSs through the generation of RCS for H2O2 and glucose detection with limit of detection of 109 nM and 21 nM in the linear ranges of 4.6 µM to 769 µM and 0.22 µM to 19.57 µM respectively. Additionally, the methodology is validated for the analysis of glucose in real samples.


Assuntos
Colorimetria , Cobre , Glucose , Peróxido de Hidrogênio , Nanoestruturas , Cobre/química , Colorimetria/métodos , Peróxido de Hidrogênio/análise , Peróxido de Hidrogênio/química , Glucose/análise , Nanoestruturas/química , Limite de Detecção , Espectroscopia Fotoeletrônica , Oxirredução , Benzidinas/química , Catálise , Humanos , Difração de Raios X , Peroxidases/metabolismo , Peroxidases/química , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Micron ; 184: 103661, 2024 09.
Artigo em Inglês | MEDLINE | ID: mdl-38833994

RESUMO

The silver/magnesium doped hydroxyapatite (AgMgHAp, Ca10-x-yAgxMgy(PO4)6(OH)2, xAg=0.05 and yMg=0.02) nanocomposites coatings were deposited on Si substrate using the dip coating technique. The resulting coatings were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR-ATR) spectroscopy, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The EDS analysis highlighted the presence of the constitutive elements of the silver/magnesium doped hydroxyapatite (AgMgHAp) nanocomposites coatings. The surface microtexture of the AgMgHAp was assessed by atomic force microscopy (AFM) technique. The AFM data suggested the obtaining of a uniform deposited layer comprised of equally distributed nanoconglomerates. FT-IR studies highlighted the presence of vibrational modes associated with the phosphate and hydroxyl groups. No bands associated with silver or magnesium were observed. The XPS analysis highlighted the presence of the constituent elements of hydroxyapatite (Ca 2p, P 2 s, O 1 s), as well as dopants (Ag 3d, Mg 1 s and Mg 2p). The antifungal evaluation of AgMgHAp coatings was carried out using the Candida albicans ATCC 10231 fungal strain. The results of the antifungal assay revealed that the AgMgHAp coatings exhibited a strong inhibitory antifungal activity. Furthermore, the data highlighted that the AgMgHAp inhibited the development of biofilm on their surface. The results revealed that the antifungal activity of the coating varied based on the duration of incubation. On the other hand, the data also showed that AgMgHAp nanocomposites coatings inhibited the fungal cell adhesion and development from the early stages of the incubation. In addition to morphological analysis, we additionally take advantage of AFM images to investigate and explore the domain of fractal and multifractal analysis applied to the films under evaluation. Our studies indicates that nanocomposite coatings made from AgMgHAp demonstrate strong antifungal properties. Our studies indicates that nanocomposite coatings made from AgMgHAp demonstrate strong antifungal properties. These results suggest the potential of AgMgHAp nanocomposite coatings as a promising solution for developing innovative antifungal devices in biomedical applications.


Assuntos
Antifúngicos , Durapatita , Magnésio , Microscopia de Força Atômica , Nanocompostos , Prata , Durapatita/química , Durapatita/farmacologia , Antifúngicos/farmacologia , Prata/farmacologia , Prata/química , Nanocompostos/química , Magnésio/química , Magnésio/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Candida albicans/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Testes de Sensibilidade Microbiana , Espectrometria por Raios X , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Propriedades de Superfície
20.
Int J Biol Macromol ; 273(Pt 1): 133096, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38866267

RESUMO

Copper ions in wastewater pose a significant threat to human and ecological safety. Therefore, preparing macroscopic adsorbents with reusable and high adsorption performance is paramount. This paper used graphene oxide as the adsorbent and chitosan as the thickener. Additionally, a silane coupling agent was employed to enhance the acid resistance of chitosan, and amino-modification of graphene oxide was performed. Macroscopic adsorbents with high adsorption capacity were fabricated using 3D printing technology. The results show that all five proportions of inks exhibit good printability. Dissolution experiments revealed that all materials maintained structural integrity after 180 days across pH values. Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) confirmed the successful preparation of the materials. Adsorption experiments showed that the best performing material ratio was 8 wt% graphene oxide and 7 wt% chitosan. Adsorption kinetics and isothermal adsorption experiments demonstrated that the adsorption process occurred via monolayer chemisorption. The adsorption process was attributed to strong electrostatic forces, van der Waals forces, and nitrogen/oxygen-containing functional group coordination. Cycling experiments showed that the material retained good adsorption performance after 6 cycles, suggesting its potential for practical heavy metal treatment applications.


Assuntos
Quitosana , Cobre , Grafite , Quitosana/química , Grafite/química , Cobre/química , Adsorção , Cinética , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Águas Residuárias/química , Reagentes de Ligações Cruzadas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Espectroscopia Fotoeletrônica
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