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Navegação por Autores IPEN "SAKATA, S.K."
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JACOVONE, R.M.S.
; SOARES, J.J.S.
; SOUSA, T.S.
; RODRIGUES, D.F.; SILVA, F.R.O.
; GARCIA, R.H.L.
; VICENTE, E.J.; SAKATA, S.K.
.
Antibacterial activity of graphene oxide/silver nanocomposite synthesized by sustainable process.
In: WORKSHOP ON ENVIRONMENTAL NANOTECHNOLOGY, 3rd,
October 5-8, 2018,
Sorocaba, SP.
Abstract...
2018.
p. 85-85.
Abstract:
Graphene oxide/silver nanocomposite has excellent antimicrobial properties [1]. The traditional methods of
incorporation of metal in graphene oxide usually require toxic reagents or with long periods of reaction and in
high temperature [2]. The objective of this study is to develop an innovative and sustainable method of
incorporating silver into graphene oxide by electron beam. This methodology does not involve toxic reagents or
residues and it is carried out in a short reaction time at room temperature. Dispersed graphene oxide was mixed
with silver in the complex form in water- isopropanol solution. The mix was submitted to a dose of radiation
varying between 150 and 400 KGy. The nanocomposite GO/Ag characterization was performed by
thermogravimetry analysis (TGA), X-ray diffraction (XDR), scanning transmission electron microscope coupled
to the energy dispersive X-ray spectrometry (TEM/EDS). The antibacterial activity of GO/Ag was observed
against Gram negative, Escherichia coli by plate count method. The viable cells of GO and GO-Ag was determined
by plating the inoculum after 4h of exposure to different concentrations of the nanomaterials (10, 50, 100, 200
and 500 μg/mL). The results showed that for 500 μg/mL of GO, inactivation cells were ca of 5,4 %, while for GOAg,
the concentration to inactivate all cell were 5 times lower (100 μg/mL). The silver nanoparticles size range
from 20 to 50 nm. This work showed that GO/Ag nanocomposites that were widely studied by their antibacterial
properties can be produce by ionizing radiation. This is a sustainable method that does not require toxic reagents
and does not generate hazardous wastes. The short reaction time of some minutes and the ambient temperature
also make the process attractive.
JACOVONE, R.M.S.; SOARES, J.J.S.; SOUSA, T.S.; RODRIGUES, D.F.; SILVA, F.R.O.; GARCIA, R.H.L.; VICENTE, E.J.; SAKATA, S.K.
Antibacterial activity of graphene oxide/silver nanocomposite synthesized by sustainable process.
In:
WORKSHOP ON ENVIRONMENTAL NANOTECHNOLOGY, 3rd,
October 5-8, 2018,
Sorocaba, SP.
Abstract...
2018.
p. 85-85.
Disponível em: http://repositorio.ipen.br/handle/123456789/30124. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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-
GALDINO, G.S.
; RODRIGUES, W.C.
; CRUZ, P.D.
; CASINI, J.S.; SAKATA, S.K.
; FARIA, R.N.
.
Characteristics of electric double layer capacitors prepared with electrolytes based on deep eutectic solvents.
In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 24.,
6-10 de novembro, 2022,
Águas de Lindóia, SP.
Resumo...
2022.
Abstract:
The storage capacity of electric double layer capacitors or electrochemical supercapacitors with
electrolytes based on deep eutectic solvents (DES) composed of L-lactic acid with several hydrogen
bond acceptors (nicotinamide, L-alanine, ammonium acetate, sodium acetate, choline chloride,
amino acetic acid) with a molar ratio of 7:1 have been investigated. A DES based on urea and
choline chloride with at a molar ration of 2:1 has also been included for comparison. The
electrochemical supercapacitors were prepared using commercial activated carbon electrodes after
removing the volatile organic electrolyte with a vacuum pump. The characteristics of the
electrochemical supercapacitors were determined by cyclic voltammetry at temperature room
temperature and also after heating at 353 K using scan rates that varied from 2 to 25 mVs-1.
Lowest scan rate led to higher specific capacitance of 150±8 Fg-1 with a maximum applied
potential of 1.7 V for the urea and choline chloride DES with a molar ration of 2:1. The lactic acid
with all the hydrogen bond acceptors with a molar ratio 7:1 it has been necessary to increase the
temperature above room temperature to improve the specific capacitance.
Palavras-Chave:
electrolytes;
capacitors;
layers;
electrochemical cells
GALDINO, G.S.; RODRIGUES, W.C.; CRUZ, P.D.; CASINI, J.S.; SAKATA, S.K.; FARIA, R.N.
Characteristics of electric double layer capacitors prepared with electrolytes based on deep eutectic solvents.
In:
CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 24.,
6-10 de novembro, 2022,
Águas de Lindóia, SP.
Resumo...
2022.
Disponível em: http://repositorio.ipen.br/handle/123456789/33835. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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-
GALDINO, G.S.
; RODRIGUES, W.C.
; CRUZ, P.D.
; CASINI, J.S.; SAKATA, S.K.
; FARIA, R.N.
.
Characteristics of electric double layer capacitors produced with electrolytes based on deep eutectic solvents.
In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 24.,
6-10 de novembro, 2022,
Águas de Lindóia, SP.
Resumo...
2022.
Abstract:
The storage capacity of electric double layer capacitors or supercapacitors with electrolytes based
on deep eutectic solvents (DES) has been investigated in this study. DES composed of L-lactic acid
with nicotinamide, L-alanine, ammonium acetate, sodium acetate and choline chloride have all
been prepared at a molar ratio of 7:1. Furthermore, urea with choline chloride at a molar ratio of
2:1 has also been used as electrolyte for the electrochemical supercapacitors. The DES
supercapacitors were prepared using commercial activated carbon electrodes after removing the
volatile organic electrolyte with back-pumping vacuum. The electric characteristics of these
supercapacitors with DES electrolytes were determined by cyclic voltammetry at room temperature
and above up to 80°C. The cyclic voltammetry scan rates were varied from 2 to 25 mVs-1. The
lowest scan rate led to a high specific capacitance of 150±8 Fg-1 for urea with choline chloride at a
molar ratio of 2:1 and using a maximum applied potential of 1.7 V. For higher molar ratio (7:1) of Llactic
acid with the others hydrogen bond acceptors (HBA) it was necessary to increase the
temperature above room temperature to improve the specific capacitance. The best results have
been obtained with two solids (urea and choline chloride) as starting compounds for preparing the
DES. Equivalent series resistances (ESR) have also been determined in this work employing
galvanostatic cycling tests with current densities between 2 and 20 mAg-1.
GALDINO, G.S.; RODRIGUES, W.C.; CRUZ, P.D.; CASINI, J.S.; SAKATA, S.K.; FARIA, R.N.
Characteristics of electric double layer capacitors produced with electrolytes based on deep eutectic solvents.
In:
CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 24.,
6-10 de novembro, 2022,
Águas de Lindóia, SP.
Resumo...
2022.
Disponível em: http://repositorio.ipen.br/handle/123456789/33742. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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JACOVONE, R.M.
; COSTA, C.A.; SAKATA, S.K.
.
Chemical characterization of bacteria: graphene oxide/Ag nanocomposite interactions by atomic force microscopy -infrared spectroscopy.
In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd,
March 4-7, 2020,
Águas de Lindoia, SP.
Abstract...
2020.
Abstract:
Atomic force microscopy -Infrared spectroscopy (AFM-IR) is a combined technique that allows nanoscale chemical characterization of biological–materials interactions. In this work, AFM-IR was used to map Escherichia coli in graphene oxide /silver nanocomposite (Ag/rGO). In Escherichia coli, it was observed absorption bands corresponding to amine I at 1660 cm-1 and amide II at 1550 cm-1 from proteins. On the other hand, when these bacteria were exposed to (Ag/rGO) typical absorption bands from carbonyl/carboxyl groups around 1745 and carbon bond around 1620 were also detected, showing the antibacterial activities of (Ag/rGO). The conventional atomic force microscope was used to elucidate the morphologic changes that occurred by internalization of nanocomposite into the bacteria. Atomic force microscopy -Infrared spectroscopy (AFM-IR) is a combined technique that allows nanoscale chemical characterization of biological–materials interactions. In this work, AFM-IR was used to map Escherichia coli in graphene oxide /silver nanocomposite (Ag/rGO). In Escherichia coli, it was observed absorption bands corresponding to amine I at 1660 cm-1 and amide II at 1550 cm-1 from proteins. On the other hand, when these bacteria were exposed to (Ag/rGO) typical absorption bands from carbonyl/carboxyl groups around 1745 cm-1 and carbon bond around 1620 cm-1 were also detected, showing the antibacterial activities of (Ag/rGO). The conventional atomic force microscope was used to elucidate the morphologic changes that occurred by internalization of nanocomposite into the bacteria.
JACOVONE, R.M.; COSTA, C.A.; SAKATA, S.K.
Chemical characterization of bacteria: graphene oxide/Ag nanocomposite interactions by atomic force microscopy -infrared spectroscopy.
In:
PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd,
March 4-7, 2020,
Águas de Lindoia, SP.
Abstract...
2020.
Disponível em: http://repositorio.ipen.br/handle/123456789/31874. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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OSHIRO, M.T.; SAKATA, S.K.; POTIENS JUNIOR, A.J.
.
Estudo das isotermas de adsorção e constante de distribuição par a remoção de sup(241)Am em rejeitos radioativos líquidos com magnetita.
In: ENCONTRO BRASILEIRO DE ADSORÇÃO, 10.,
27-30 de abril, 2014,
Guarujá, SP.
Anais...
2014.
Palavras-Chave:
magnetite;
removal;
adsorption isotherms;
distribution functions;
americium 241;
radioactive wastes;
evaluation
OSHIRO, M.T.; SAKATA, S.K.; POTIENS JUNIOR, A.J.
Estudo das isotermas de adsorção e constante de distribuição par a remoção de sup(241)Am em rejeitos radioativos líquidos com magnetita.
In:
ENCONTRO BRASILEIRO DE ADSORÇÃO, 10.,
27-30 de abril, 2014,
Guarujá, SP.
Anais...
2014.
Disponível em: http://repositorio.ipen.br/handle/123456789/26342. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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BENITEZ JARA, F.G.
; CRUZ, P.V.
; BARBOSA, L.P.; CASINI, J.C.S.; PERUZZI, A.J.; SAKATA, S.K.
; FARIA, R.N.
.
Low-temperature reduction of graphene oxide using the HDDR process for electrochemical supercapacitor applications.
In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 2922-2922.
Abstract:
In the present work, attempts of reducing a graphene oxide powder using a low
temperature hydrogenation disproportionation desorption and recombination process
(L-HDDR) has been carried out. A lower processing temperature in large scale
production is significant as far as costs are concerned. Graphite oxide was prepared
using a modified Hummers’ method and dispersed in ethanol, exfoliated using
ultrasonication to produce Graphene Oxide (GO). Investigations have been carried out
by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental
results of L-HDDR processing graphene oxide powder using unmixed hydrogen at
400°C and relatively low pressures (<2 bars) have been reported. X-ray diffraction
patterns showed a reduction of graphene oxide with the L-HDDR process. The results
showed that the L-HDDR process, as the standard HDDR process, can be applied to
the reduction of graphene oxide to produce supercapacitor materials. The advantage
of employing the L-HDDR process is a relatively a low temperature would reduce the
cost of treatment that is a very important factor for producing large amount of material.
Thus, the L-HDDR process has been considered a promising alternative method of
reducing graphene oxide with efficiency and possibly in large scale production.
BENITEZ JARA, F.G.; CRUZ, P.V.; BARBOSA, L.P.; CASINI, J.C.S.; PERUZZI, A.J.; SAKATA, S.K.; FARIA, R.N.
Low-temperature reduction of graphene oxide using the HDDR process for electrochemical supercapacitor applications.
In:
CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 2922-2922.
Disponível em: http://repositorio.ipen.br/handle/123456789/29627. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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BENITEZ JARA, F.G.
; CRUZ, P.D.V.
; BARBOSA, L.P.
; CASINI, J.C.S.; SAKATA, S.K.
; PERUZZI, A.J.; FARIA, R.N.
.
Low-temperature reduction of graphene oxide using the HDDR process for electrochemical supercapacitor applications.
Materials Science Forum,
v. 1012,
p. 141-146,
2020.
DOI:
10.4028/www.scientific.net/MSF.1012.141
Abstract:
In the present work, attempts of reducing a graphene oxide powder using a low
temperature hydrogenation disproportionation desorption and the recombination process (L-HDDR)
has been carried out. A lower processing temperature in large scale production is significant when
costs are concerned. Graphite oxide was prepared using a modified Hummers’ method dispersed in
ethanol and exfoliated using ultrasonication to produce Graphene Oxide (GO). Investigations have
been carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The
experimental results of L-HDDR processing graphene oxide powder, using unmixed hydrogen at
400°C and relatively low pressures (<2 bars) have been reported. X-ray diffraction patterns showed
a reduction of graphene oxide with the L-HDDR process. The results showed that both processes,
the L-HDDR as well as the standard HDDR, may be applied to the reduction of graphene oxide in
order to produce supercapacitor materials. The advantage of employing the L-HDDR process is a
relatively low temperature reducing the cost of treatment, what is a very important factor for
producing a large amount of material. Thus, the L-HDDR process has been considered a promising
alternative method of reducing graphene oxide with efficiency, with the possibility of large scale
production.
Palavras-Chave:
graphene;
capacitors;
energy storage;
capacitance;
equivalent circuits;
hydrogenation;
desorption;
recombination
BENITEZ JARA, F.G.; CRUZ, P.D.V.; BARBOSA, L.P.; CASINI, J.C.S.; SAKATA, S.K.; PERUZZI, A.J.; FARIA, R.N.
Low-temperature reduction of graphene oxide using the HDDR process for electrochemical supercapacitor applications.
Materials Science Forum,
v. 1012,
p. 141-146,
2020.
DOI:
10.4028/www.scientific.net/MSF.1012.141.
Disponível em: http://200.136.52.105/handle/123456789/31638. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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-
GALDINO, G.S.
; SILVA, D.V.
; CRUZ, P.D.
; CASINI, J.S.; SAKATA, S.K.
; FARIA, R.N.
.
Microstructural and electrochemical studies of HDDR-graphene supercapacitors electrodes in KOH electrolyte.
In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 2923-2923.
Abstract:
In the past, the hydrogenation disproportionation desorption and recombination
(HDDR) process has only been used to produced rare earth transition metal polymer
bonded permanent magnets with outstanding performance. Recently, however, it has
been shown that the HDDR process (850oC) can be successfully employed to produce
reduced graphene oxide for electrochemical supercapacitors. In the present work, the
electrochemical characteristics of HDDR-graphene supercapacitors have been
compared to those obtained with chemically reduced commercial graphene oxide.
Lower HDDR processing temperatures (200-600oC) have been used in this study for
a comparison with previous investigations. The equivalent series and parallel
resistances (EPR and ESR) and specific capacitance (Cs) of HDDR-graphene
supercapacitors electrodes have been investigated using cyclic voltammetry. Room
temperature specific capacitances calculated from cyclic voltammetry curves at scan
rates of 2 mVs-1 reached ~160 Fg-1 in 1 molL-1 KOH electrolyte. Internal series
resistances of the HDDR-graphene electrodes were measured using the galvanostatic
curves also at room temperature. The microstructures of the electrode material have
been investigated using scanning electron microscopy (SEM) and chemical
microanalyses employing energy dispersive X-ray analysis (EDX).
GALDINO, G.S.; SILVA, D.V.; CRUZ, P.D.; CASINI, J.S.; SAKATA, S.K.; FARIA, R.N.
Microstructural and electrochemical studies of HDDR-graphene supercapacitors electrodes in KOH electrolyte.
In:
CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 2923-2923.
Disponível em: http://repositorio.ipen.br/handle/123456789/29628. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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CASTRO, B.; CONTI, S.M.; OSHIRO, M.T.; SAKATA, S.K..
Remoção do corante textil violeta reativo 5 utilizando bagaço de cana-de-açucar nas formas bruta e ativada.
In: ENCONTRO BRASILEIRO DE ADSORÇÃO, 10.,
27-30 de abril, 2014,
Guaruja, SP.
Anais...
2014.
Palavras-Chave:
aqueous solutions;
dyes;
absorbents;
bagasse;
sugar cane;
textile industry
CASTRO, B.; CONTI, S.M.; OSHIRO, M.T.; SAKATA, S.K.
Remoção do corante textil violeta reativo 5 utilizando bagaço de cana-de-açucar nas formas bruta e ativada.
In:
ENCONTRO BRASILEIRO DE ADSORÇÃO, 10.,
27-30 de abril, 2014,
Guaruja, SP.
Anais...
2014.
Disponível em: http://repositorio.ipen.br/handle/123456789/23722. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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SAKATA, S.K.
; SOBRINHO, L.F.
; JACOVONE, R.M.S.
; SOARES, J.J.S.
; TOMINAGA, F.K.
; ANGNES, L.; GARCIA, R.H.L.
.
Sustainable synthesis of transition metals/graphene oxide nanocomposites by electron beam irradiation.
In: PAN AMERICAN CONGRESS OF NANOTECHNOLOGY, 1st,
27-30 de novembro, 2017,
Guarujá, SP.
Abstract...
2017.
Abstract:
Graphene is nanomaterial with unique physical and chemical properties that makes it a precursor for the synthesis of new materials, such as conductive nanocomposites. Graphene can be obtained by the reduction of graphene oxide, but when it is incomplete, reduced graphene oxide (rGO) is produced with both graphene and graphene oxide properties: it is electrical and thermal conductor, it can be exfoliated in several polar solvents and moreover, the oxygen groups can later be functionalized, affording nanocomposites for electrochemical applications and also in biomaterials.
A method of increasing the electrical conductivity of graphene-based compounds is by the incorporation of metallic nanoparticles. When these nanomaterials are joined together the surface area increases for the passage of electric current and the electrical conductivity. The chemical reduction method for the incorporation of metallic nanoparticle on GO involves toxic reagents or it is a time-consuming and it also requires high costs for the removal of excess reagents and by-products. The general synthesis of transition Metal/graphene-based nanocomposites by the electron beam in a sustainable process will be presented. The experiments were performed in a 1.5 MeV electron accelerator at room temperature and no hazardous wastes were generated. The nanocomposites were characterized by FT-IR, DRX and TEM/EDS as metallic nanoparticle at the average size of 5-20 nm incorporated into reduced graphene oxide layers. The electrochemical behavior of these nanocomposites was evaluated by cyclic voltammetry.
SAKATA, S.K.; SOBRINHO, L.F.; JACOVONE, R.M.S.; SOARES, J.J.S.; TOMINAGA, F.K.; ANGNES, L.; GARCIA, R.H.L.
Sustainable synthesis of transition metals/graphene oxide nanocomposites by electron beam irradiation.
In:
PAN AMERICAN CONGRESS OF NANOTECHNOLOGY, 1st,
27-30 de novembro, 2017,
Guarujá, SP.
Abstract...
2017.
Disponível em: http://repositorio.ipen.br/handle/123456789/29052. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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JACOVONE, R.M.S.
; SOARES, J.J.S.
; SAKATA, S.K.
.
Synthesis and characterization of graphene oxide/nickel nanoparticles using nanoparticle tracking analysis.
In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 4682-4682.
Abstract:
One of the graphene based compounds that has giving attention is graphene oxide
(GO). This nanomaterial has oxygenated groups on its surface, which provide
hydrophilicity and allow its exfoliation in several polar solvents. Moreover, these
reactive sites can be further functionalized, yielding nanocomposites with many
applications in electrochemistry and biomaterials fields. The objective of this study is
to synthesize nickel / graphene oxide (GO-Ni) nanocomposite using electron beam in
water /alcohol solution without stabilizers and to characterize GO and GO-Ni by
Nanoparticle Tracking Analysis (NTA). The Nanoparticle Tracking Analysis utilizes the
properties of both light scattering and Brownian motion in order to obtain the particle
size distribution and to measure the diffusion coefficient. From the Stokes-Einstein
equation it was possible to obtain the hydrodynamic diameter of the nanomaterials.
The NTA result showed that GO and GO-Ni showed respectively 47 nm and 55nm.
Both showed a low polydispersity index, indicating the homogeneity of the size
distribution and the formation of a monodisperse system. The results showed that it is
possible to obtain nanoparticles of graphene oxide incorporated with nickels smaller
than 60 nm and with good distribution without the use of stabilizers.
JACOVONE, R.M.S.; SOARES, J.J.S.; SAKATA, S.K.
Synthesis and characterization of graphene oxide/nickel nanoparticles using nanoparticle tracking analysis.
In:
CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 4682-4682.
Disponível em: http://repositorio.ipen.br/handle/123456789/29554. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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TOMINAGA, F.K.
; SAKATA, S.K.
; SOARES, J.J.S.
; JACOVONE, R.M.S.
.
Synthesis and characterization of magnetic graphene oxide nanocomposites.
In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 4680-4680.
Abstract:
Graphene oxide (GO) is a unique material that can be described as a single
monomolecular layer of graphite containing various oxygen functionalities such as
epoxide, carbonyl, carboxyl and hydroxyl groups. Chemical modifications at the
surface of the graphene oxide through the incorporation of magnetite can provide
magnetic properties to these nanomaterials. This work aims to synthesize and
characterize graphene oxide/magnetite (GO/M) nanocomposites, evaluating the
different proportions of incorporated magnetite. The synthesis of graphene
oxide/magnetite nanocomposites was performed by co-precipitation of iron salts on the
graphene oxide (GO) particles in alkaline medium. The characterization of the
nanocomposites was performed by thermogravimetric analysis (TGA), infrared
spectroscopy (FTIR), X-ray diffraction (XRD), nanoparticle tracking analysis (NTA) and
scanning electron microscopy (SEM). The thermogravimetric results showed the
incorporation of approximately 20, 50, 70 and 80% of magnetite to the graphene oxide.
Regarding the hydrodynamic size, for the magnetite, mode values of 31.3 ± 1.3 nm
were determined, whereas for the GO/M, the mode values of size ranged from 72.8 to
194 nm. The results of XRD and FTIR showed the respective characteristic diffraction
and absorption peaks only for graphene oxide, magnetite and GO/M(20%). It was not
observed characteristic peaks for the other samples of graphene oxide that have
higher loads of magnetite incorporated.
TOMINAGA, F.K.; SAKATA, S.K.; SOARES, J.J.S.; JACOVONE, R.M.S.
Synthesis and characterization of magnetic graphene oxide nanocomposites.
In:
CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 4680-4680.
Disponível em: http://repositorio.ipen.br/handle/123456789/29553. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
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-
SOARES, J.J.S.
; SANTOS, P.S.
; ZAIM, M.H.; SAKATA, S.K.
.
The effect of gamma radiation on the stability of aqueous dispersions of graphene oxide and graphene oxide functionalized with amino-peg.
In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 2343-2343.
Abstract:
Nanocomposites based on graphene have been prominent in the field of biomedicine
due to the biocompatibility with the physiological medium and the possibility of being
functionalized by a series of biocompatible polymers, such as chitosan, polyethylene
glycol, poly (caprolactone), among others. However, there is a need for sterilization of
these nanomaterials in the medical field and gamma irradiation is a promising option.
In the present work graphene oxide (GO), produced by the modified Hummers method,
was functionalized with amino-PEG (GO-PEG-NH2) through the amidation process.
The objective of this study was to evaluate the aqueous dispersions stability of these
nanomaterials before and after gamma radiation (Cobalt 60) at a dose of 25 kGy.
Dynamics light scattering (DLS) was used to determine the zeta potential. The results
showed no significant differences between the zeta potentials of the non-irradiated and
irradiated graphene oxide. The dispersion of the functionalized graphene oxide
showed to be stable and the irradiated unstable.
SOARES, J.J.S.; SANTOS, P.S.; ZAIM, M.H.; SAKATA, S.K.
The effect of gamma radiation on the stability of aqueous dispersions of graphene oxide and graphene oxide functionalized with amino-peg.
In:
CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23.,
04-08 de novembro, 2018,
Foz do Iguaçu, PR.
Resumo...
2018.
p. 2343-2343.
Disponível em: http://repositorio.ipen.br/handle/123456789/29525. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
Como referenciar este item
-
SOARES, J.J.S.
; JACOVONE, R.M.S.
; SANTOS, P.S.
; ZAIM, M.H.; FARIA, D.L.A.; SAKATA, S.K.
.
The effect of gamma radiation on the structure of graphene oxide and graphene oxide functionalized with amino-PEG.
Brazilian Journal of Radiation Sciences,
v. 7,
n. 3,
p. 1-12,
2019.
DOI:
10.15392/bjrs.v7i3.837
Abstract:
Covalent functionalization of graphene oxide (GO) with polyethylene glycol (PEG) has been widely used in drug delivery systems. This nanocomposite exhibits excellent stability in the presence of high concentrations of salts and proteins and shows low toxicity compared to its raw form. However, it must be sterilized prior to use in medical devices, and for this purpose, the gamma irradiation shows a promising option. Sterilization by ionizing energy through gamma rays, generated by Cobalt-60 self-disintegration, consists in exposing the materials to short electromagnetic waves. The irradiation process provides substantial advantages when compared to thermal and chemical processes, such as, more precise control of the process, lower energy consumption, and less environmental pollution. In this work the effects of gamma radiation on GO and GO functionalized with amino-PEG (GO-PEG-NH2) irradiated with doses (15, 25, 35 and 50 kGy) at rate dose of 7.3 kGy.h-1 were evaluated. The analyses were performed by Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The results showed that gamma radiation up to 50 kGy did not cause any defects on the nanomaterials.
Palavras-Chave:
cobalt 60;
dose rates;
fourier transformation;
gamma radiation;
graphene;
infrared spectra;
polyethylene glycols;
radiation doses;
radiation effects;
raman spectroscopy;
sterilization;
synthesis
SOARES, J.J.S.; JACOVONE, R.M.S.; SANTOS, P.S.; ZAIM, M.H.; FARIA, D.L.A.; SAKATA, S.K.
The effect of gamma radiation on the structure of graphene oxide and graphene oxide functionalized with amino-PEG.
Brazilian Journal of Radiation Sciences,
v. 7,
n. 3,
p. 1-12,
2019.
DOI:
10.15392/bjrs.v7i3.837.
Disponível em: http://repositorio.ipen.br/handle/123456789/30484. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
Como referenciar este item
-
CARDOSO, Q.A.
; SILVA, F.M.; VIEIRA, L.S.; CASINI, J.C.S.; SAKATA, S.K.
; FARIA, R.N.
.
The production of reduced graphene oxide by a low-cost vacuum system for supercapacitors applications.
In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIENCIA DOS MATERIAIS, 22.,
06-10 de novembro, 2016,
Natal, RN.
Proceedings...
2016.
p. 4022-4029.
Abstract:
Graphene (G) has attracted great interest for its excellent electrical properties. However, the large-scale production of graphene is still currently under investigations. Graphene oxide (GO) can be partially reduced to graphene-like sheets by removing the oxygen-containing groups with the recovery of a conjugated structure. It can be produced using inexpensive graphite as raw material by cost-effective chemical methods. High vacuum and temperature (10-7mbar/1100oC) is well established as an effective route for reduced powder preparation on a laboratory scale. However, a high vacuum reduction system, which can be routinely operated at 10-7 mbar, has a considerable capital, operational and maintenance cost to be used in a large scale. In the present work, a low-cost route aiming large scale reduction of graphene oxide has been investigated. A stainless steel vessel has been evacuated to backing-pump pressure (10-2 mbar) to process graphene oxide at low and high temperatures. Attempts of reducing GO powder using low vacuum pressures have been carried out and investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The experimental results of processing graphene oxide powder at various temperatures (200-1000°C) at relatively low pressures have been reported. The microstructures of the processed material have been investigated using scanning electron microscopy (SEM) and chemical microanalyses employing energy dispersive X-ray analysis (EDX).
Palavras-Chave:
capacitors;
fourier transformation;
graphene;
infrared spectra;
microstructure;
oxides;
production;
reduction;
scanning electron microscopy;
temperature dependence;
x-ray diffraction
CARDOSO, Q.A.; SILVA, F.M.; VIEIRA, L.S.; CASINI, J.C.S.; SAKATA, S.K.; FARIA, R.N.
The production of reduced graphene oxide by a low-cost vacuum system for supercapacitors applications.
In:
CONGRESSO BRASILEIRO DE ENGENHARIA E CIENCIA DOS MATERIAIS, 22.,
06-10 de novembro, 2016,
Natal, RN.
Proceedings...
2016.
p. 4022-4029.
Disponível em: http://repositorio.ipen.br/handle/123456789/27244. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
Como referenciar este item
-
KAWABATA, V.J.
; CARNEIRO, F.W.
; JACOVONE, R.M.
; ALMEIDA, E.V. de; GARCIA, R.H.
; CORIO, P.; SAKATA, S.K.
.
The synthesis of magnetite/reduced graphene oxide nanocomposites by electron beam for eletrocatalysis application.
In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd,
March 4-7, 2020,
Águas de Lindoia, SP.
Abstract...
2020.
Abstract:
This work presents the synthesis of magnetite/reduced graphene oxide nanocomposites (MrGO) via electron beam. The graphene oxide (GO) was prepared according to a modified Hummers’ method and it was characterized using X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Raman spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), zeta potential analysis and cyclic voltammetry (CV) were used in order to investigate the structure and properties of MGO. The data showed GO was reduced using 40 kGy. The CV was performed by applying a MrGO layer on the working electrode of a screen-printed carbon electrode, at a scan rate of 50 mVs-1, potentials range from -0.5 V until 1.0 V in KCl medium (0.05 mol.L-1) adding aliquots of 4 mmol L ?1 ferrocyanide solution. Its results show a similar electrochemical response from both samples (maximum current: 45?A). It can therefore be inferred that magnetite/reduced graphene oxide nanocomposites have a potential for electrocatalysis application.
KAWABATA, V.J.; CARNEIRO, F.W.; JACOVONE, R.M.; ALMEIDA, E.V. de; GARCIA, R.H.; CORIO, P.; SAKATA, S.K.
The synthesis of magnetite/reduced graphene oxide nanocomposites by electron beam for eletrocatalysis application.
In:
PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd,
March 4-7, 2020,
Águas de Lindoia, SP.
Abstract...
2020.
Disponível em: http://repositorio.ipen.br/handle/123456789/31891. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
Como referenciar este item
-
CARNEIRO, F.W.
; KAWABATA, V.J.
; JACOVONE, R.M.
; ANGNES, L.; GARCIA, R.H.
; SAKATA, S.K.
.
The synthesis of palladium nanoparticles by electron beam into graphene oxide and its electrochemical behavior.
In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd,
March 4-7, 2020,
Águas de Lindoia, SP.
Abstract...
2020.
Abstract:
In this work, graphene oxide (GO) was synthesized by the modified Hummers method and was used as support for palladium nanoparticles to study its electrochemical behavior. The main objective was the incorporation of Pd on the graphene oxide by the electron beam irradiation at 40kGy and 80kGy doses. The GO-Pd nanocomposite was characterized by thermogravimetry analysis (TGA), X-ray diffraction (XRD), electron transmission microscopy (TEM), zeta potential analysis and cyclic voltammetry (CV). The results were satisfactory, indicating success in incorporating the metal in the GO surface. CV studies were conducted using screen printed electrode modified with nanocomposite, SPE/GO-Pd, at a scan rate of 50 mVs-1, potentials range from -0.5 V until 1.0 V in KCl medium (0.05 mol.L-1) adding aliquots of 4 mmol L ?1 ferricyanide solution and its results showed a linear increase in the current. It can therefore be inferred that palladium /graphene oxide nanocomposites have a potential for sensors.
CARNEIRO, F.W.; KAWABATA, V.J.; JACOVONE, R.M.; ANGNES, L.; GARCIA, R.H.; SAKATA, S.K.
The synthesis of palladium nanoparticles by electron beam into graphene oxide and its electrochemical behavior.
In:
PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd,
March 4-7, 2020,
Águas de Lindoia, SP.
Abstract...
2020.
Disponível em: http://repositorio.ipen.br/handle/123456789/31892. Acesso em: $DATA.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.
Como referenciar este item
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O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.
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clique aqui.
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Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.
A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.
O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.