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1.
Biosens Bioelectron ; 142: 111594, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31430612

RESUMO

We report a novel anode electrocatalyst, iron carbide nanoparticles dispersed in porous graphitized carbon (Nano-Fe3C@PGC), which is synthesized by facile approach involving a direct pyrolysis of ferrous gluconate and a following removal of free iron, but provides microbial fuel cells with superior performances. The physical characterizations confirm the unique configuration of iron carbide nanoparticles with porous graphitized carbon. Electrochemical measurements demonstrate that the as-synthesized Nano-Fe3C@PGC exhibits an outstanding electrocatalytic activity toward the charge transfer between bacteria and anode. Equipped with Nano-Fe3C@PGC, the microbial fuel cells based on a mixed bacterium culture yields a power density of 1856 mW m-2. The resulting excellent performance is attributed to the large electrochemical active area and the high electronic conductivity that porous graphitized carbon provides and the enriched electrochemically active microorganisms and enhanced activity towards the redox reactions in microorganisms by Fe3C nanoparticles.


Assuntos
Fontes de Energia Bioelétrica , Compostos Inorgânicos de Carbono/química , Grafite/química , Compostos de Ferro/química , Nanoestruturas/química , Fontes de Energia Bioelétrica/economia , Fontes de Energia Bioelétrica/microbiologia , Compostos Inorgânicos de Carbono/economia , Catálise , Condutividade Elétrica , Eletrodos , Desenho de Equipamento , Grafite/economia , Compostos de Ferro/economia , Nanopartículas/química , Nanopartículas/economia , Nanopartículas/ultraestrutura , Nanoestruturas/economia , Nanoestruturas/ultraestrutura , Porosidade
2.
J Photochem Photobiol B ; 197: 111515, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31255939

RESUMO

An extraordinary arrangement of research is as yet going on in the area of orthopedic implants advancement to determine different issues being looked by the engineering today. In spite of a few detriments of the orthopedic metallic inserts, they keep on being utilized, essentially as a result of their unrivaled mechanical properties. We investigated the conceivable utilization of silicon carbide (SiC) as a nano-ceramic covering material of titanium (Ti)-based all out femoral substitution implants. The thought is to keep wear garbage arrangement from the delicate titanium exterior. Silicon carbide is a hard and firmly holding bio-ceramic surface substance, and in light of these physico-chemical properties, it isn't actually degradable, just like the case with apatite (HA). To improve cytocompatibility and osseous-integration, we deposited anodized titanium nanotubes (TiO2) inserts, by electrochemical deposition method (EDM), with silicon carbide (SiC) with apatite (SiC@HA). The deposition was affirmed by SEM, while phase composition properties were assessed by XRD. Calcium affidavit, osteocalcin creation, and articulation of bone genes were essentially higher in rodent osteoblast cell culture on SiC@HA-covered anodized titanium nanotubes than in cells cultured on uncoated anodized titanium nanotubes. Implantation into rodent femurs likewise demonstrated that the SiC@HA-covered substance had unrivaled osseous-integration movement in correlation with that of customary inserts, as evaluated by in vivo tomography and histology. Therefore, anodized titanium nanotubes covered with SiC@HA holds guarantee as an orthopedic implant substance.


Assuntos
Regeneração Óssea , Compostos Inorgânicos de Carbono/química , Materiais Revestidos Biocompatíveis/química , Durapatita/química , Nanopartículas/química , Compostos de Silício/química , Titânio/química , Animais , Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Adesão Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/uso terapêutico , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Fraturas do Fêmur/terapia , Regulação da Expressão Gênica/efeitos dos fármacos , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteocalcina/metabolismo , Próteses e Implantes , Ratos
3.
Anal Chim Acta ; 1073: 30-38, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31146833

RESUMO

Highly N-doped SiC was presented as an optimal electrode for electrochemical immunoassays with a far higher sensitivity than chemiluminescence detection. As the first step, the electrochemical properties of highly N-doped SiC, such as the double-layer capacitance (Cdl), rate constant for electron transfer (kapp) and ideal polarizable potential range (electrochemical window) were analyzed and compared with those of Au, Pt, and graphite electrodes. The highly N-doped SiC electrode was used for the quantification of oxidized 3,3',5,5'-tetramethylbenzidine (TMB) which was widely used as chromogenic substrate for commercialized immunoassay kits. In order to enhance the sensitivity for the quantification of the oxidized TMB the chronoamperometry was applied to avoid the background current of i-V measurement. Finally, the chronoamperometry based on the highly N-doped SiC electrode was applied to commercial immunoassay kits for the medical diagnosis of the human immunodeficiency virus (HIV) and the human hepatitis B surface antigen (hHBsAg). The chronoamperometric measurement based on the highly N-doped SiC electrode was proved to detect at far lower limits in comparison with the conventional optical density measurement as well as the chemiluminescence assay based on luminol as a chemiluminescent probe.


Assuntos
Benzidinas/análise , Técnicas Biossensoriais , Compostos Inorgânicos de Carbono/química , Técnicas Eletroquímicas , HIV/isolamento & purificação , Antígenos de Superfície da Hepatite B/isolamento & purificação , Imunoensaio , Compostos de Silício/química , Eletrodos , Humanos
4.
Artigo em Inglês | MEDLINE | ID: mdl-30938573

RESUMO

A study was conducted to characterize the raw wastewater entering a modern cost effective municipal WWTP in Poland using two approaches; 1) a combination of modeling and carbonaceous oxygen demand (COD) fractionation using respirometric test coupled with model estimation (RT-ME) and 2) flocculation/filtration COD fractionation method combined with BOD measurements (FF-BOD). It was observed that the particulate fractions of COD obtained using FF-BOD method was higher than those estimated by RT-ME approach. Contrary to the above, the values of inert soluble fraction evaluated by FF-BOD method was significantly lower than RT-ME approach (2.4% and 3.9% respectively). Furthermore, the values for low colloidal and particulate fractions as well as soluble inert fractions were different than expected from a typical municipal wastewater. These observations suggest that even at low load (10% of the total wastewater treatment inflow), the industrial wastewater composition can significantly affect the characteristics of municipal wastewater which could also affect the performance and accuracy of respirometric tests. Therefore, in such cases, comparison of the respirometric tests with flocculation/filtration COD/BOD measurements are recommended. Oxygen uptake rate profile with settled wastewater and/or after coagulation-flocculation, however, could still be recommended as a "rapid" control method for monitoring/optimising modern cost-effective wastewater treatment plants.


Assuntos
Análise da Demanda Biológica de Oxigênio , Esgotos/química , Eliminação de Resíduos Líquidos/economia , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Análise da Demanda Biológica de Oxigênio/métodos , Análise da Demanda Biológica de Oxigênio/normas , Calibragem , Compostos Inorgânicos de Carbono/química , Fracionamento Químico/métodos , Cidades , Análise Custo-Benefício , Monitoramento Ambiental/métodos , Monitoramento Ambiental/normas , Filtração , Floculação , Humanos , Oxigênio/química , Polônia , Purificação da Água/economia , Purificação da Água/métodos , Purificação da Água/normas
5.
Environ Sci Process Impacts ; 21(3): 564-574, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30723847

RESUMO

The global SiC market is projected to grow in the coming years, and research on potential health effects as well as epidemiological studies is therefore of importance. A detailed characterization in terms of the phase composition, morphology and mixing state of airborne PM is still missing, though highly necessary to identify sources and to understand the risk factors in this industry. Particles in the size range of 10 nm to 10 µm were collected with a 13-stage NanoMOUDI impactor in the Acheson Furnace Hall as well as in processing departments during two sampling campaigns. Particle mass concentrations, including the fraction of ultrafine particles (UFPs), were lower in the processing departments in comparison to those in the Acheson Furnace Hall. The particle number size distribution measured with a scanning mobility particle sizer confirmed the low amount of UFPs in the processing departments compared to the furnace hall. Significant differences in the particle mass concentration and distribution were observed in the Acheson Furnace Hall during the two sampling campaigns. The PM size distribution depends upon the sampling location, on the cycle of the nearby furnaces and on special incidents occurring during a furnace run. Scanning and transmission electron microscopy (SEM and TEM) showed that the size range of 0.32-10 µm (aerodynamic diameter) is dominated by carbon (C)-rich particles, which were identified as petroleum coke, graphite, soot and amorphous spherical C-rich particles. Soot was further classified into three types based on the primary particle size, morphology and composition. Diesel-powered vehicles, pyrolysis of petroleum coke and incomplete combustion of volatile components from this pyrolysis are suggested as sources of different soot particle types. Amorphous spherical C-rich particles were also sub-classified based on their morphology and composition as tar balls (TBs) and C-spherical type 2. The amount of SiC fibers and crystalline SiO2 was found to be low. In the size fraction below 0.32 µm (aerodynamic diameter), sulphur (S)-rich particles dominate. This knowledge of the particle size distribution, and chemical and physical properties of the PM occurring in the SiC production is fundamental for an appropriate risk assessment, and these findings should have implications for future epidemiological studies and for the mitigation of worker exposure.


Assuntos
Poluentes Ocupacionais do Ar/análise , Compostos Inorgânicos de Carbono/química , Indústria Química , Monitoramento Ambiental/métodos , Material Particulado/análise , Compostos de Silício/química , Noruega , Tamanho da Partícula , Fuligem/química
6.
Int J Biol Macromol ; 128: 941-947, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30716367

RESUMO

In the present study, a novel and high efficient magnetic alginate beads containing Fe5C2@SiO2 nanoparticles (NPs) were synthesized and applied to remove Cu (II) ions from water. The synthesized Fe5C2@SiO2 NPs were characterized by scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The elemental content of the magnetic/alginate beads before and after Cu(II) adsorption was analyzed using energy dispersive X-ray spectroscopy (EDS). The influence of important factors such as pH, contact time and initial Cu (II) concentration on the adsorption capacity of magnetic/alginate beads was investigated. The maximum adsorption percent (97.4%) was attained in the pH range of 3-4 and the adsorbent dosage of 0.41 g/L in the Cu (II) concentration of 200 mg/L. Moreover, the maximum capacity of adsorption was compared with silica coated iron carbide alginate and alginate alone. The results showed with adding a 1 mg of silica coated iron carbide NPs to sodium alginate enhanced the adsorption capacity of copper ions to ca. 2 times. The Sips isotherm model was best fitted to the experimental data with the maximum adsorption capacity of 37.73 mg/g for each layer. The adsorption kinetic followed the pseudo-second order kinetic model. These results reveal that the alginate Fe5C2@SiO2 beads could be a candidate for copper ions removal from aqueous solutions.


Assuntos
Alginatos/química , Compostos Inorgânicos de Carbono/química , Cobre/química , Compostos de Ferro/química , Imãs/química , Microesferas , Dióxido de Silício/química , Água/química , Adsorção , Cobre/isolamento & purificação , Concentração de Íons de Hidrogênio , Soluções , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
7.
Artigo em Inglês | MEDLINE | ID: mdl-30720755

RESUMO

Previous studies on the water quality of surface runoff often focused on the chemical oxygen demand (COD), nitrogen, phosphorus, and total suspended solid (TSS), but little is known in terms of the inorganic suspended solids (ISS). This research investigated the effects of ISS carried by surface runoff on the treatment efficiency of the pretreatment facilities and the ratio of mixed liquor volatile suspended solid to mixed liquor suspended solid (MLVSS/MLSS) of the activated sludge in a wastewater treatment plant (WWTP) with the anaerobic-anoxic-oxic (AAO) process in Chongqing city, China. The results showed that the surface runoff had a long-lasting impact on the grit removal capacity of the grit chamber, affecting the normal operation after the rainfall. In contrast, the primary sedimentation tank showed strong impact resistance with higher removal rates of COD, TSS, and ISS. Nonetheless, the primary settling tank aggravates the removal of organic carbon in sewage during rainfall, having a negative impact on subsequent biological treatment. The ISS in the surface runoff could increase the sludge concentration and decrease the MLVSS/MLSS ratio. After repeated surface runoff impact, the MLVSS/MLSS ratio in the activated sludge would drop below even 0.3, interrupting the normal operation of WWTP.


Assuntos
Compostos Inorgânicos de Carbono/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes da Água/química , China
8.
Sci Total Environ ; 666: 155-164, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30798226

RESUMO

This study evaluated the feasibility of using a silicon carbide (SiC) anaerobic ceramic membrane bioreactor (AnCMBR) to co-manage domestic wastewater (DWW) and food waste recycling wastewater (FRW). A pilot-scale SiC-AnCMBR was put into operation for 140 days under two different organic loading rates (OLRs): 5 kg COD m-3 d-1 (OLR 5) and 3 kg COD m-3 d-1 (OLR 3). The organic removal efficiency was 93.5 ±â€¯3.7% over the operational period. Methane production increased significantly after sludge re-seeding at OLR 3. rDNA and rRNA microbial results showed that the active archaeal community was affected by sludge re-seeding, whereas the active bacterial community was not, indicating that a shift in the active archaeal community was responsible for the increased methane production. Our results thus suggest that SiC-AnCMBRs are a promising option for co-managing DWW and FRW.


Assuntos
Reatores Biológicos/microbiologia , Compostos Inorgânicos de Carbono/química , DNA Ribossômico/análise , Microbiota , RNA Ribossômico/análise , Compostos de Silício/química , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Cerâmica , Membranas Artificiais
9.
ACS Sens ; 4(2): 406-412, 2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30663312

RESUMO

Gas sensors, which play an important role in the safety of human life, cover a wide range of applications including intelligent systems and detection of harmful and toxic gases. It is known that graphene is an ideal and attractive candidate for gas sensing due to its high surface area and excellent mechanical, electrical, optical, and thermal properties. However, in order to fully realize its potential as a commercial gas sensor, demand for a graphene-based device of low-limit detection, high sensitivity, and fast response time needs to be met. Here, we demonstrate a metal/insulator/semiconductor (MIS) based gas sensor consisting of as-grown epitaxial graphene nanowalls (EGNWs)/silicon carbide (SiC)/silicon (Si) structure. The unique edge dominant three-dimensional (3D) EGNWs based MIS device achieved an extraordinarily low limit of detection (0.5 ppm) and unprecedented sensitivity (82 µA/ppm/cm2 for H2) with a fast response of shorter than 500 ms. These unique properties of our MIS device are attributed to the abundance of vertically oriented nanographitic edges and structural defects that act as extra-favorable adsorption sites and exhibit fast electron-transfer kinetics through the edges. Our experimental findings can pave the way for the realization of high-performance 3D graphene-based gas sensor devices.


Assuntos
Compostos Inorgânicos de Carbono/química , Técnicas de Química Analítica/instrumentação , Gases/análise , Grafite/química , Limite de Detecção , Nanoestruturas/química , Compostos de Silício/química , Silício/química , Pressão Atmosférica , Hidrogênio/análise , Oxigênio/análise , Temperatura
10.
Anal Chim Acta ; 1049: 188-195, 2019 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-30612650

RESUMO

An electrochemical immunosensor for ultrasensitive detection of acrylamide (AA) in water and food samples was developed. SnO2-SiC hollow sphere nanochains with high surface area and gold nanoparticles with good electroconductivity were fabricated onto the surface of a glassy carbon electrode pre-coated with chitosan. The coating antigen (AA-4-mercaptophenylacetic acid-ovalbumin conjugate, AA-4-MPA-OVA) was immobilized on the electrode. Polyclonal antibody specific for AA-4-MPA was conjugated to gold nanorod (AuNR) as primary antibody (AuNR-Ab1). Horseradish peroxidase labelled anti-rabbit antibody produced in goat was conjugated to AuNR as secondary antibody (HRP-AuNR-Ab2). For detection, the analyte (AA-4-MPA) in sample competed with coating antigen for binding with AuNR-Ab1. After washing, HRP-AuNR-Ab2 was added to capture the AuNR-Ab1, and the electrical signal was obtained by addition of hydroquinone and H2O2. After investigation of the binding ability on nanomaterials and optimization of competitive immunoassay conditions, the proposed immunosensor exhibited a sensitive response to AA with a detection limit of 45.9 ±â€¯2.7 ng kg-1, and working range of 187 ±â€¯12.3 ng kg-1 to 104 ±â€¯8.2 µg kg-1 for drinking water samples. Recoveries of AA from spiked samples were ranged from 86.0% to 115.0%. The specificity, repeatability and stability of the immunosensor were also proved to be acceptable, indicating its potential application in AA monitoring.


Assuntos
Acrilamida/análise , Técnicas Eletroquímicas/métodos , Imunoensaio/métodos , Nanotubos/química , Acrilamida/imunologia , Anticorpos/imunologia , Técnicas Biossensoriais/métodos , Compostos Inorgânicos de Carbono/química , Quitosana/química , Café/química , Água Potável/análise , Contaminação de Alimentos/análise , Ouro/química , Limite de Detecção , Ovalbumina/imunologia , Fenilacetatos/imunologia , Compostos de Silício/química , Solanum tuberosum/química , Compostos de Sulfidrila/imunologia , Compostos de Estanho/química
11.
ACS Nano ; 12(11): 11000-11012, 2018 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-30339353

RESUMO

Therapeutic nanosystems which can be triggered by the distinctive tumor microenvironment possess great selectivity and safety to treat cancers via in situ transformation of nontoxic prodrugs into toxic therapeutic agents. Here, we constructed intelligent, magnetic targeting, and tumor microenvironment-responsive nanocatalysts that can acquire oxidation therapy of cancer via specific reaction at tumor site. The magnetic nanoparticle core of iron carbide-glucose oxidase (Fe5C2-GOD) achieved by physical absorption has a high enzyme payload, and the manganese dioxide (MnO2) nanoshell as an intelligent "gatekeeper" shields GOD from premature leaking until reaching tumor tissue. Fe5C2-GOD@MnO2 nanocatalysts maintained inactive in normal cells upon systemic administration. On the contrary, after endocytosis by tumor cells, tumor acidic microenvironment induced decomposition of MnO2 nanoshell into Mn2+ and O2, meanwhile releasing GOD. Mn2+ could serve as a magnetic resonance imaging (MRI) contrast agent for real-time monitoring treatment process. Then the generated O2 and released GOD in nanocatalysts could effectively exhaust glucose in tumor cells, simultaneously generating plenty of H2O2 which may accelerate the subsequent Fenton reaction catalyzed by the Fe5C2 magnetic core in mildly acidic tumor microenvironments. Finally, we demonstrated the tumor site-specific production of highly toxic hydroxyl radicals for enhanced anticancer therapeutic efficacy while minimizing systemic toxicity in mice.


Assuntos
Antineoplásicos/farmacologia , Terapia de Campo Magnético , Nanopartículas/química , Microambiente Tumoral/efeitos dos fármacos , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/patologia , Animais , Antineoplásicos/química , Compostos Inorgânicos de Carbono/química , Compostos Inorgânicos de Carbono/farmacologia , Catálise , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Células HeLa , Humanos , Compostos de Ferro/química , Compostos de Ferro/farmacologia , Imagem por Ressonância Magnética , Compostos de Manganês/química , Compostos de Manganês/farmacologia , Camundongos , Camundongos Endogâmicos , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/patologia , Óxidos/química , Óxidos/farmacologia , Tamanho da Partícula , Propriedades de Superfície
12.
Molecules ; 23(9)2018 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-30205564

RESUMO

Silicon carbide (SiC) has a large number of polytypes of which 3C-, 4H-, 6H-SiC are most common. Since different polytypes have different energy gaps and electrical properties, it is important to identify and characterize various SiC polytypes. Here, Raman scattering is performed on 6H-SiC micro/nanocrystal (MNC) films to investigate all four folded transverse optic (TO) and longitudinal optic (LO) modes. With increasing film thickness, the four folded TO modes exhibit the same frequency downshift, whereas the four folded LO modes show a gradually-reduced downshift. For the same film thickness, all the folded modes show larger frequency downshifts with decreasing MNC size. Based on plasmons on MNCs, these folded modes can be attributed to strong coupling of the folded phonons with plasmons which show different strengths for the different folded modes while changing the film thickness and MNC size. This work provides a useful technique to identify SiC polytypes from Raman scattering.


Assuntos
Compostos Inorgânicos de Carbono/química , Hidrogênio/química , Fônons , Compostos de Silício/química , Nanopartículas , Tamanho da Partícula , Análise Espectral Raman , Propriedades de Superfície
13.
Environ Pollut ; 243(Pt A): 218-227, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30176495

RESUMO

The increased release and accumulation of Bisphenol A (BPA) in contaminated wastewater has resulted in the world wide concerns because of its potential negative effects on human health and aquatic ecosystems. Starting with metal-organic frameworks, we present a simple method to synthesize magnetic porous microcubes (N-doped Fe0/Fe3C@C) with graphitized shell and highly dispersed active kernel via the pyrolysis process under N2 atmosphere. Batch adsorption experimental results showed that N-doped Fe0/Fe3C@C had high adsorption capacity for BPA (∼138 mg g-1 at pH = 7 and 298 K). Degradation of BPA adsorbed on N-doped Fe0/Fe3C@C was further investigated as a function of BPA concentration, persulfate amount, temperature and solution pH. It was found that potassium peroxodisulfate could be activated by N-doped Fe0/Fe3C@C, and a large number of free radicals were generated which was crucial for the degradation of BPA. The concentration of BPA was barely changed in the individual persulfate system. BPA (10 mg L-1) was almost completely degraded within 60 min in the presence of N-doped Fe0/Fe3C@C (∼0.2 g L-1). When the BPA content increased to 25 mg L-1, the removal efficiency of BPA achieved to 98.4% after 150 min. From the XRD, Raman, and XPS analysis, the main adsorption mechanism of BPA was π-π interactions between the π orbital on the carbon basal planes and the electronic density in the BPA aromatic rings. While the superior degradation was attributed to the radical generation and evolution in phenol oxidation. This work not only proved the potential application of N-doped Fe0/Fe3C@C in the adsorption and degradation of BPA, but also opened the new possibilities to eliminate organic pollutants using this kind of magnetic materials in organic pollutants' cleanup.


Assuntos
Adsorção , Compostos Benzidrílicos/análise , Compostos Inorgânicos de Carbono/química , Carbono/química , Recuperação e Remediação Ambiental/métodos , Compostos de Ferro/química , Nanopartículas de Magnetita/química , Oxirredução , Fenóis/análise , Humanos , Ferro/química , Compostos de Potássio/química , Sulfatos/química
14.
J Photochem Photobiol B ; 187: 113-119, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30121421

RESUMO

Sulfate reducing bacteria (SRB) wreaks havoc in the oil industry by being an agent for oil souring and building corrosion in pipelines and thereby degrade the quality of crude oil. Palladium nanoparticles decorated silicon carbide nanomaterial (Pd-SiC) was synthesized by a facile single step synthesis process and this nanomaterial as a photo-catalyst, as compared to pure silicon carbide (SiC) nanoparticles showed a significant enhancement in the photo-catalytic efficiency in the process of the photo-catalytic deactivation of hazardous SRB. The morphological characterization studies such as Field emission scanning electron microscopy, Transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy unambiguously revealed that SiC surface was successfully decorated with palladium (Pd) nanoparticles. Also the Pd nanoparticles decorated on the SiC surface was further substantiated by EDX and elemental mapping analysis, which clearly revealed the presence of Pd along with Si and O. The band gap energy estimated using Diffuse reflectance spectra (DRS) showed the reduction of band gap energy from 2.82 eV to 2.72 eV. The observed enhancement in the efficiency of photo-catalytic deactivation of SRB with Pd-SiC can be attributed to the significant reduction in the recombination of photo-generated charge carriers, characteristically resulting from the metal (Pd) semiconductor (SiC) junction established by this synthesis process.


Assuntos
Bactérias/metabolismo , Compostos Inorgânicos de Carbono/química , Nanopartículas Metálicas/química , Nanopartículas/química , Paládio/química , Compostos de Silício/química , Sulfatos/química , Bactérias/efeitos dos fármacos , Catálise , Luz , Nanopartículas Metálicas/toxicidade , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanopartículas/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfatos/metabolismo , Difração de Raios X
15.
Chem Commun (Camb) ; 54(58): 8132-8135, 2018 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-29975377

RESUMO

Submicron Ti3AlC2 grains are grown in molten salt. Etching the grains gives rise to small-sized Ti3C2Tx MXene particulates with capacitance more than twice that of the large ones derived from conventional high-temperature synthesis. Detailed electrochemical, structural, and spectroscopic studies demonstrate that increased capacitance predominantly originates from a decrease in the lateral size of the small Ti3C2Tx MXene particulates.


Assuntos
Compostos de Alumínio/química , Compostos Inorgânicos de Carbono/química , Titânio/química , Compostos de Alumínio/síntese química , Compostos Inorgânicos de Carbono/síntese química , Cristalização , Capacitância Elétrica , Tamanho da Partícula , Cloreto de Potássio/química , Cloreto de Sódio/química
16.
Biomaterials ; 179: 60-70, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29980075

RESUMO

Silicon carbide has been shown to be biocompatible and is used as a coating material for implanted medical devices to prevent biofilms. Silicon carbide nanomaterials are also promising in cell tracking due to their stable and strong luminescence, but more comprehensive studies of this material on the nanoscale are needed. Here, we studied the toxicity of silicon carbide nanomaterials on human mesenchymal stem cells in terms of metabolism, viability, adhesion, proliferation, migration, oxidative stress, and differentiation ability. We compared two different shapes and found that silicon carbide nanowires are toxic to human mesenchymal stem cells but not to cancer cell lines at the concentration of 0.1 mg/mL. Control silicon carbide nanoparticles were biocompatible to human mesenchymal stem cells at 0.1 mg/mL. We studied the potential mechanistic effect of silicon carbide nanowires on human mesenchymal stem cells' phenotype, cytokine secretion, and gene expression. These findings suggest that the toxic effect of silicon carbide nanomaterials to human mesenchymal stem cells are dependent on morphology.


Assuntos
Compostos Inorgânicos de Carbono/química , Nanoestruturas/química , Nanofios/química , Compostos de Silício/química , Adesão Celular/fisiologia , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Sobrevivência Celular/fisiologia , Citocinas/química , Humanos , Células-Tronco Mesenquimais/citologia , Estresse Oxidativo/fisiologia
17.
Mater Sci Eng C Mater Biol Appl ; 91: 135-145, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30033240

RESUMO

In order to improve the mechanical properties of nano hydroxyapatite (HA), silicon carbide whisker (SiCw) with excellent mechanical and biological properties was used as the reinforcement for SiC whisker reinforced nano hydroxyapatite (SiCw/HA) composites. Hydrothermal synthesis method was adopted to prepare the uniformly dispersed SiCw and HA composite powders, and SiCw/HA composites were fabricated by pressureless sintering. The interfacial bonding state and mechanical properties of SiCw/HA composites in different sintering atmospheres (air and N2) were systematically investigated. The results show that the uniformity of the composite powders decreases with the increase of SiCw content, and the cross-section of SiCw/HA composites gradually changes from glossy and smooth to rough and undulate. When the content of SiCw is 15 wt%, the maximum bending strength and fracture toughness of the composites sintered in air atmosphere (HAW15) are 40.85 MPa and 1.82 MPa·m1/2 respectively, which are higher than those of pure HA. Compared with those of the SiCw/HA composites sintered in N2 atmosphere, the bending strength and fracture toughness of the HAW15 composites are increased by 154.2% and 10.3%, respectively. Moreover, Simulated body fluid (SBF) and in vitro cell behavior tests indicate that the SiCw/HA composites still have excellent bioactivity. The possible strengthening and toughening mechanisms of SiCw/HA composites are that the dispersion of SiCw in HA matrix is improved by hydrothermal process, and the interfacial bonding property is enhanced because of the reaction fusion on interface of SiCw/HA composites during sintering in air atmosphere. The adoption of hydrothermal process improves the dispersion uniformity of SiCw in HA matrix. When sintering in air atmosphere, the interfacial bonding property of SiCw/HA composite is enhanced via the reaction fusion (SiO2 is formed by the oxidation of SiCw). Both of them lead to the increase of strength and toughness of the composites. This study would provide additional insights into the feasibility of SiCw/HA composites as load-bearing implant materials in orthopedic applications.


Assuntos
Atmosfera , Compostos Inorgânicos de Carbono/química , Durapatita/química , Nanocompostos/química , Nanopartículas/química , Compostos de Silício/química , Animais , Linhagem Celular , Fenômenos Mecânicos , Camundongos , Nanocompostos/ultraestrutura , Nanopartículas/ultraestrutura , Temperatura , Difração de Raios X
18.
Bioresour Technol ; 267: 257-264, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30025322

RESUMO

Considering a series of issues facing the application of catalysts in large scale catalytic fast pyrolysis systems, a novel composite catalyst of ZSM-5 coatings on SiC foam supports was developed and tested for ex-situ catalytic upgrading of the pyrolytic vapors. Different configurations of catalysts placement were compared and the results showed the composite catalyst could significantly improve the bio-oil quality without significantly reducing the yield. The effect of catalyst to biomass ratio on the product yields and bio-oil composition was studied and the results showed that increasing catalyst to biomass ratio could improve the quality of bio-oil at the cost of its yield. In addition, the composite catalyst can maintain its activity until a catalyst to biomass ratio of 1/10, outperforming ZSM-5 in other configurations reported in literature. Furthermore, the composite catalysts could be regenerated and reused while well preserving its material properties and catalytic activity after seven reaction-regeneration cycles.


Assuntos
Biocombustíveis , Compostos Inorgânicos de Carbono/química , Micro-Ondas , Compostos de Silício/química , Biomassa , Catálise
19.
Molecules ; 23(7)2018 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-29941846

RESUMO

The selective oxidation of H2S to elemental sulfur was carried out on a NiS2/SiCfoam catalyst under reaction temperatures between 40 and 80 °C using highly H2S enriched effluents (from 0.5 to 1 vol.%). The amphiphilic properties of SiC foam provide an ideal support for the anchoring and growth of a NiS2 active phase. The NiS2/SiC composite was employed for the desulfurization of highly H2S-rich effluents under discontinuous mode with almost complete H2S conversion (nearly 100% for 0.5 and 1 vol.% of H2S) and sulfur selectivity (from 99.6 to 96.0% at 40 and 80 °C, respectively), together with an unprecedented sulfur-storage capacity. Solid sulfur was produced in large aggregates at the outer catalyst surface and relatively high H2S conversion was maintained until sulfur deposits reached 140 wt.% of the starting catalyst weight. Notably, the spent NiS2/SiCfoam catalyst fully recovered its pristine performance (H2S conversion, selectivity and sulfur-storage capacity) upon regeneration at 320 °C under He, and thus, it is destined to become a benchmark desulfurization system for operating in discontinuous mode.


Assuntos
Compostos Inorgânicos de Carbono/química , Sulfeto de Hidrogênio/química , Níquel/química , Compostos de Silício/química , Catálise , Temperatura Baixa , Oxirredução , Enxofre/química
20.
Phys Chem Chem Phys ; 20(19): 13419-13429, 2018 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-29722404

RESUMO

Ultrasmall silicon carbide nanoparticles (SiC USNPs) are very promising biomarkers for developing new applications in diagnostics, cell monitoring or drug delivery, even though their interaction with biological molecules such as different proteins has not yet been investigated in detail. In this study, the biological behaviour of SiC USNPs in a medium modeling a living organism was investigated in detail through the dependence of the fluorescence on interactions between bovine serum albumin (BSA) and SiC USNPs. The interaction shows transient nanoparticle-protein associations due to the restricted diffusion behaviour of the nanoparticles in the vicinity of a protein. The transient association manifests in a complex fluorescence quenching mechanism where the dynamic component was dominated by Förster resonance energy transfer. By studying SiC nanoparticles of different sizes, it can be concluded that the transient effect is an ultrasmall nanoparticle behaviour.


Assuntos
Compostos Inorgânicos de Carbono/química , Corantes Fluorescentes/química , Nanopartículas/química , Soroalbumina Bovina/química , Compostos de Silício/química , Animais , Sítios de Ligação , Biomarcadores/química , Bovinos , Transferência Ressonante de Energia de Fluorescência , Cinética , Tamanho da Partícula , Ligação Proteica , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Propriedades de Superfície , Termodinâmica
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