Nanomateriais cerâmicos por reação de combustão, 2021
Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia... more Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia de Materiais da UFCG. Atua no desenvolvimento de novos materiais via síntese química, atividades relacionadas à nanotecnologia e desenvolvimento de materiais para aplicação em eletro-eletrônica, catálise, materiais magnéticos, ópticos, nanocompósitos, biomateriais, membranas cerâmicas e marcadores biológicos. Possui experiência em síntese e caracterização de materiais, desenvolvimento de materiais magnéticos para aplicações em catálise, absorvedores de radiação eletromagnética, marcadores biológicos e dispositivos magnéticos moles. Participa como membro permanente do Programa de Pós-Graduação em Ciências e Engenharia de Materiais (conceito CAPES 5). Também atua na formação de recursos humanos participando ativamente dos programas
Novas tecnologias aplicadas à engenharia biomédica: Uma Contribuição à Engenharia de Tecidos
Imagens da Capa: EDS/MEV de scaffolds de quitosana/hidroxiapatita/amoxilina. Fonte: Ponciano, J. ... more Imagens da Capa: EDS/MEV de scaffolds de quitosana/hidroxiapatita/amoxilina. Fonte: Ponciano, J. J. (2021). Scaffolds de quitosana e hidroxiapatita com amoxicilina para reparação óssea na cavidade bucal. 114f. Tese de Doutorado, Campina Grande-PB, UFCG.
Nanomateriais cerâmicos por reação de combustão, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia... more Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia de Materiais da UFCG. Atua no desenvolvimento de novos materiais via síntese química, atividades relacionadas à nanotecnologia e desenvolvimento de materiais para aplicação em eletro-eletrônica, catálise, materiais magnéticos, ópticos, nanocompósitos, biomateriais, membranas cerâmicas e marcadores biológicos. Possui experiência em síntese e caracterização de materiais, desenvolvimento de materiais magnéticos para aplicações em catálise, absorvedores de radiação eletromagnética, marcadores biológicos e dispositivos magnéticos moles. Participa como membro permanente do Programa de Pós-Graduação em Ciências e Engenharia de Materiais (conceito CAPES 5). Também atua na formação de recursos humanos participando ativamente dos programas
Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia... more Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia de Materiais da UFCG. Atua no desenvolvimento de novos materiais via síntese química, atividades relacionadas à nanotecnologia e desenvolvimento de materiais para aplicação em eletro-eletrônica, catálise, materiais magnéticos, ópticos, nanocompósitos, biomateriais, membranas cerâmicas e marcadores biológicos. Possui experiência em síntese e caracterização de materiais, desenvolvimento de materiais magnéticos para aplicações em catálise, absorvedores de radiação eletromagnética, marcadores biológicos e dispositivos magnéticos moles. Participa como membro permanente do Programa de Pós-Graduação em Ciências e Engenharia de Materiais (conceito CAPES 5). Também atua na formação de recursos humanos participando ativamente dos programas
Nanomateriais cerâmicos por reação de combustão, 2021
Recently, sleep has been recognized as a crucial factor for health and longevity. The daily sleep... more Recently, sleep has been recognized as a crucial factor for health and longevity. The daily sleep/wake cycle provides the basis of biorhythm, which controls whole-body homeostasis and homeodynamics. Sleep disturbances can contribute to several physical and psychological disorders, including cardiovascular disease, obesity, depression, and cognitive dysfunction. The clinical use of the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine began in the 1970s. Over the years, physicians have used it as a short-acting anesthetic, analgesic, and antidepressant; however, indepth research has revealed new possible applications for ketamine, such as for treating sleep disturbances and circadian rhythm disorders. The aim of this narrative review is to examine the literature on the mechanistic role of the antidepressant ketamine in affecting sleep disturbance. Additionally, we discuss the pharmacologic and pharmacokinetic mechanisms of ketamine as an antidepressant and the predictive biomarkers for ketamine's effect on sleep and cognitive function.
Nanomateriais cerâmicos por reação de combustão, 2021
Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia... more Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia de Materiais da UFCG. Atua no desenvolvimento de novos materiais via síntese química, atividades relacionadas à nanotecnologia e desenvolvimento de materiais para aplicação em eletro-eletrônica, catálise, materiais magnéticos, ópticos, nanocompósitos, biomateriais, membranas cerâmicas e marcadores biológicos. Possui experiência em síntese e caracterização de materiais, desenvolvimento de materiais magnéticos para aplicações em catálise, absorvedores de radiação eletromagnética, marcadores biológicos e dispositivos magnéticos moles. Participa como membro permanente do Programa de Pós-Graduação em Ciências e Engenharia de Materiais (conceito CAPES 5). Também atua na formação de recursos humanos participando ativamente dos programas
Mundialmente, muta atencao tem sido focada na utilizacao da biomassa vegetal para a producao dos ... more Mundialmente, muta atencao tem sido focada na utilizacao da biomassa vegetal para a producao dos chamados “materiais de engenharia”. Dentre a variedade de produtos,o biodiesel ocupa uma posicao de destaque, nao so em termos de quantidade produzida no mundo, mas tambem devido suas caracteristicas relacionadas a energia limpa, porque reune caracteristicas singulares como renovabilidade, biodegradabilidade e beneficio ambiental. Muitas pesquisas sao realizadas para produzir materiais avancados que incrementem o processo de producao do biodiesel,por exemplo, catalisadores que exibam conjuntamente alta atividade, seletividade,resistencia, filtrabilidade, regenerabilidade para reutilizacao, e, por conseguinte, minimizem os custos globais de obtencao do biodiesel. Este trabalho se propoe a sintetizar por reacao de combustao, em escala piloto, nanocatalisadores magneticos de Ni0,5Zn0,5Fe2O4 e avaliar seu desempenho em reacoes de (trans)esterificacao para obtencao de biodiesel. Os nanocatali...
Abstract The synthesis of the Ni0.5-xZn0.5-xCu2xFe2O4 (x = 0; 0.10 and 0.15) ferrite with the dif... more Abstract The synthesis of the Ni0.5-xZn0.5-xCu2xFe2O4 (x = 0; 0.10 and 0.15) ferrite with the differential of pilot-scale production by the combustion reaction method was investigated for RAM application purposes. Combustion temperatures ranging from 682 °C to 738 °C were observed. All ferrites were sintered at 1200 °C for 1 h. A comprehensive study of the influence of substitution with Cu2+ in a partial and proportional way to the Ni2+ and Zn2+ ions, doping mode little reported in the literature, and also of the sintering process over the structural, textural, morphological, magnetic and electromagnetic properties of NiZnCu ferrites was performed. The XRD patterns of the ferrites as synthesized revealed the formation of the cubic structure of the inverse spinel as majoritary phase, and traces of hematite and zinc oxide as segregated phases. After sintering, it was proven the single-phase formation of cubic spinel ferrite structure. The introduction of Cu led to a reduction in the lattice parameter, whose values ranged from 8.337 to 8.385 A. The EDX results confirm the composition of oxides. The textural and morphological analyses confirmed the densest characteristic, with increase of particle size and reducing of surface area and pore volume after Cu-doping. All ferrites showed characteristics of soft ferrimagnetic material, where the increase in Cu content contributed to a slight reduction in saturation magnetization, whose values were of ~22–29 emu/g for the as synthesized ferrites and ~71–85 emu/g for the sintered ones. The best result of electromagnetic absorption in X-band was presented by the sintered ferrite with 0.3 mol of Cu, reaching an attenuation of 99.8% at 11.5 GHz frequency, thus confirming the efficiency of the pilot-scale combustion synthesis in obtaining a ferrite with great potential for RAM application.
Biodiesel is a biodegradable fuel derived from renewable biomass, such as soybean and cottonseed ... more Biodiesel is a biodegradable fuel derived from renewable biomass, such as soybean and cottonseed oil, which may be obtained by different processes and requires a material to catalyze the obtaining reactions. The irons spinel comes overlapping as excellent materials to catalyze the biodiesel production reactions. Thus, the purpose of this work was the use of Ni0.5Zn0.5Fe2O4 nanoferrite as a catalyst in esterification reactions. The nanoferrite was synthesized by combustion in large scale, 200g/batch, where time and the temperature of the reactions were measured, and characterized by XRD and measuring its surface area. The biodiesel was obtained from methyl and ethyl esterification of acidified soybean oil and cottonseed, at a temperature of 160°C for 1 hour, molar ratio 1:15, 3% of catalyst and analyzed by chromatography. The nanoferrite has shown peaks of greater intensity corresponding to a majority crystal phase of the spinel and a surface area of 64.17m2/g. The conversion resul...
Ni0.5Zn0.5Fe2O4 catalyst was synthesized by combustion method Important reaction parameters w... more Ni0.5Zn0.5Fe2O4 catalyst was synthesized by combustion method Important reaction parameters were evaluated Transesterification reaction kinetic for soybean oil and methanol was determined Biodiesel was produced by transesterification method using Ni0.5Zn0.5Fe2O4 catalyst SUMMARY Biodiesel was successfully produced by transesterification process of soybean oil and methanol using Ni0.5Zn0.5Fe2O4 nanomagnetic catalyst. The Ni0.5Zn0.5Fe2O4 catalyst was synthesized by the combustion method and its properties were investigated using X-ray diffraction (XRD), N2 physisorption at 77 K, Fourier transform infrared analysis (FT-IR), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and a transmission electron microscopy (TEM). The performance of catalyst was investigated during transesterification reaction for FAMEs production. Fatty acid methyl esters (FAMEs) were studied by gas chromatography (GC) technique. The effect of reaction conditions such as molar ratio of methanol/soybean oil, catalyst amount, reaction temperature and reaction time on FAMEs yield were also evaluated. The biodiesel yield of 92.1 % was obtained under the following reaction conditions: 9:1 of methanol/soybean oil molar ratio and, 2 % of catalyst loading at 180 °C in 3 h. Furthermore, the energy of activation (Ea) was 67.4 kJ.mo1-1 and the pre-exponential factor (ko) was 8.35×10 4 L mol −1 min −1 determined using Arrhenius equation.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
This research proposes to obtain iron spinels MFe 2 O 4 , and their hybrids MFe 2 O 4 @SiO 2 and ... more This research proposes to obtain iron spinels MFe 2 O 4 , and their hybrids MFe 2 O 4 @SiO 2 and MFe 2 O 4 @SiO 2 / chitosan (M = Cu, Ni, Co, Mn e Fe) from the surface modification with (3-aminopropyl)trimethoxysilane agent and functionalization with chitosan, and then evaluate them as to their structure, morphology, magnetism and cytotoxicity, towards obtaining biocompatible hybrids for biological applications. The samples were analyzed by XRD, FTIR, SEM, TEM, magnetic measurements and in vitro cytotoxicity. XRD results showed that all samples presented the formation of the desired spinel major phase, with a crystallite size between 12 and 45 nm. According to the morphology and FTIR spectra of the samples, it was possible to confirm the formation of the hybrids. All samples presented soft magnetic material characteristics, exception given to the iron spinels CoFe 2 O 4 , which showed characteristic of hard magnetic material. The best results of cell viability were obtained by the CoFe 2 O 4 , MnFe 2 O 4 e Fe 3 O 4 MNPs and their hybrids.
Nanotechnology has been important in improving of the properties of the materials used in the man... more Nanotechnology has been important in improving of the properties of the materials used in the manufacture of magnetic devices, electromagnetic radiation absorbers, cell telephony, pigments and lately in catalysis in transesterification and esterification reactions to biodiesel obtaining. The objective of this work was to synthesize and characterize magnetic materials of spinel type compound of CuFe2O4, CoFe2O4, MnFe2O4, NiFe2O4 and FeFe2O4 and to check the catalytic effect on the methyl esterification reaction of soybean oil. The samples were obtained by combustion reaction and characterized by XRD, FTIR, BET and SEM. The results analysis revealed for nanoferrites the spinel phase formation and higher specific area to the sample CoFe2O4. Generally the samples presented in irregular agglomerates form. All samples were catalytically active in the esterification reaction, with the highest conversion obtained by the sample MnFe2O4 with 57%.
Magnetic catalysts are easily removed from the reaction process, thereby reducing the wastewater ... more Magnetic catalysts are easily removed from the reaction process, thereby reducing the wastewater generation. Therefore, the study proposes to evaluate the performance of the nanomagnetic catalyst Ni0.5Zn0.5Fe2O4 in the transesterification reaction of the soybean oil to produce biodiesel, varying processing conditions (temperature, molar ratio of oil:alcohol and catalyst amount) on the catalytic reaction. The catalyst was synthesized by combustion reaction and characterized by XRD, BET, magnetic measurements and gas chromatography. The results revealed the inverse spinel phase formation, type B(AB)2O4, with isotherm profile classified as type V with hysteresis loop of type 3 (H3), and surface area of 48.39 m2g-1. The magnetic hysteresis curve showed a characteristic behavior of soft magnetic material with saturation magnetization value of 55 emu/g. Chromatographic analysis confirmed that the magnetic nanoparticles are catalytically active and that the processing conditions directly...
Nanomateriais cerâmicos por reação de combustão, 2021
Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia... more Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia de Materiais da UFCG. Atua no desenvolvimento de novos materiais via síntese química, atividades relacionadas à nanotecnologia e desenvolvimento de materiais para aplicação em eletro-eletrônica, catálise, materiais magnéticos, ópticos, nanocompósitos, biomateriais, membranas cerâmicas e marcadores biológicos. Possui experiência em síntese e caracterização de materiais, desenvolvimento de materiais magnéticos para aplicações em catálise, absorvedores de radiação eletromagnética, marcadores biológicos e dispositivos magnéticos moles. Participa como membro permanente do Programa de Pós-Graduação em Ciências e Engenharia de Materiais (conceito CAPES 5). Também atua na formação de recursos humanos participando ativamente dos programas
Novas tecnologias aplicadas à engenharia biomédica: Uma Contribuição à Engenharia de Tecidos
Imagens da Capa: EDS/MEV de scaffolds de quitosana/hidroxiapatita/amoxilina. Fonte: Ponciano, J. ... more Imagens da Capa: EDS/MEV de scaffolds de quitosana/hidroxiapatita/amoxilina. Fonte: Ponciano, J. J. (2021). Scaffolds de quitosana e hidroxiapatita com amoxicilina para reparação óssea na cavidade bucal. 114f. Tese de Doutorado, Campina Grande-PB, UFCG.
Nanomateriais cerâmicos por reação de combustão, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia... more Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia de Materiais da UFCG. Atua no desenvolvimento de novos materiais via síntese química, atividades relacionadas à nanotecnologia e desenvolvimento de materiais para aplicação em eletro-eletrônica, catálise, materiais magnéticos, ópticos, nanocompósitos, biomateriais, membranas cerâmicas e marcadores biológicos. Possui experiência em síntese e caracterização de materiais, desenvolvimento de materiais magnéticos para aplicações em catálise, absorvedores de radiação eletromagnética, marcadores biológicos e dispositivos magnéticos moles. Participa como membro permanente do Programa de Pós-Graduação em Ciências e Engenharia de Materiais (conceito CAPES 5). Também atua na formação de recursos humanos participando ativamente dos programas
Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia... more Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia de Materiais da UFCG. Atua no desenvolvimento de novos materiais via síntese química, atividades relacionadas à nanotecnologia e desenvolvimento de materiais para aplicação em eletro-eletrônica, catálise, materiais magnéticos, ópticos, nanocompósitos, biomateriais, membranas cerâmicas e marcadores biológicos. Possui experiência em síntese e caracterização de materiais, desenvolvimento de materiais magnéticos para aplicações em catálise, absorvedores de radiação eletromagnética, marcadores biológicos e dispositivos magnéticos moles. Participa como membro permanente do Programa de Pós-Graduação em Ciências e Engenharia de Materiais (conceito CAPES 5). Também atua na formação de recursos humanos participando ativamente dos programas
Nanomateriais cerâmicos por reação de combustão, 2021
Recently, sleep has been recognized as a crucial factor for health and longevity. The daily sleep... more Recently, sleep has been recognized as a crucial factor for health and longevity. The daily sleep/wake cycle provides the basis of biorhythm, which controls whole-body homeostasis and homeodynamics. Sleep disturbances can contribute to several physical and psychological disorders, including cardiovascular disease, obesity, depression, and cognitive dysfunction. The clinical use of the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine began in the 1970s. Over the years, physicians have used it as a short-acting anesthetic, analgesic, and antidepressant; however, indepth research has revealed new possible applications for ketamine, such as for treating sleep disturbances and circadian rhythm disorders. The aim of this narrative review is to examine the literature on the mechanistic role of the antidepressant ketamine in affecting sleep disturbance. Additionally, we discuss the pharmacologic and pharmacokinetic mechanisms of ketamine as an antidepressant and the predictive biomarkers for ketamine's effect on sleep and cognitive function.
Nanomateriais cerâmicos por reação de combustão, 2021
Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia... more Doutora em Ciências dos Materiais pela UFSCar em 2002 e professora Titular do Curso de Engenharia de Materiais da UFCG. Atua no desenvolvimento de novos materiais via síntese química, atividades relacionadas à nanotecnologia e desenvolvimento de materiais para aplicação em eletro-eletrônica, catálise, materiais magnéticos, ópticos, nanocompósitos, biomateriais, membranas cerâmicas e marcadores biológicos. Possui experiência em síntese e caracterização de materiais, desenvolvimento de materiais magnéticos para aplicações em catálise, absorvedores de radiação eletromagnética, marcadores biológicos e dispositivos magnéticos moles. Participa como membro permanente do Programa de Pós-Graduação em Ciências e Engenharia de Materiais (conceito CAPES 5). Também atua na formação de recursos humanos participando ativamente dos programas
Mundialmente, muta atencao tem sido focada na utilizacao da biomassa vegetal para a producao dos ... more Mundialmente, muta atencao tem sido focada na utilizacao da biomassa vegetal para a producao dos chamados “materiais de engenharia”. Dentre a variedade de produtos,o biodiesel ocupa uma posicao de destaque, nao so em termos de quantidade produzida no mundo, mas tambem devido suas caracteristicas relacionadas a energia limpa, porque reune caracteristicas singulares como renovabilidade, biodegradabilidade e beneficio ambiental. Muitas pesquisas sao realizadas para produzir materiais avancados que incrementem o processo de producao do biodiesel,por exemplo, catalisadores que exibam conjuntamente alta atividade, seletividade,resistencia, filtrabilidade, regenerabilidade para reutilizacao, e, por conseguinte, minimizem os custos globais de obtencao do biodiesel. Este trabalho se propoe a sintetizar por reacao de combustao, em escala piloto, nanocatalisadores magneticos de Ni0,5Zn0,5Fe2O4 e avaliar seu desempenho em reacoes de (trans)esterificacao para obtencao de biodiesel. Os nanocatali...
Abstract The synthesis of the Ni0.5-xZn0.5-xCu2xFe2O4 (x = 0; 0.10 and 0.15) ferrite with the dif... more Abstract The synthesis of the Ni0.5-xZn0.5-xCu2xFe2O4 (x = 0; 0.10 and 0.15) ferrite with the differential of pilot-scale production by the combustion reaction method was investigated for RAM application purposes. Combustion temperatures ranging from 682 °C to 738 °C were observed. All ferrites were sintered at 1200 °C for 1 h. A comprehensive study of the influence of substitution with Cu2+ in a partial and proportional way to the Ni2+ and Zn2+ ions, doping mode little reported in the literature, and also of the sintering process over the structural, textural, morphological, magnetic and electromagnetic properties of NiZnCu ferrites was performed. The XRD patterns of the ferrites as synthesized revealed the formation of the cubic structure of the inverse spinel as majoritary phase, and traces of hematite and zinc oxide as segregated phases. After sintering, it was proven the single-phase formation of cubic spinel ferrite structure. The introduction of Cu led to a reduction in the lattice parameter, whose values ranged from 8.337 to 8.385 A. The EDX results confirm the composition of oxides. The textural and morphological analyses confirmed the densest characteristic, with increase of particle size and reducing of surface area and pore volume after Cu-doping. All ferrites showed characteristics of soft ferrimagnetic material, where the increase in Cu content contributed to a slight reduction in saturation magnetization, whose values were of ~22–29 emu/g for the as synthesized ferrites and ~71–85 emu/g for the sintered ones. The best result of electromagnetic absorption in X-band was presented by the sintered ferrite with 0.3 mol of Cu, reaching an attenuation of 99.8% at 11.5 GHz frequency, thus confirming the efficiency of the pilot-scale combustion synthesis in obtaining a ferrite with great potential for RAM application.
Biodiesel is a biodegradable fuel derived from renewable biomass, such as soybean and cottonseed ... more Biodiesel is a biodegradable fuel derived from renewable biomass, such as soybean and cottonseed oil, which may be obtained by different processes and requires a material to catalyze the obtaining reactions. The irons spinel comes overlapping as excellent materials to catalyze the biodiesel production reactions. Thus, the purpose of this work was the use of Ni0.5Zn0.5Fe2O4 nanoferrite as a catalyst in esterification reactions. The nanoferrite was synthesized by combustion in large scale, 200g/batch, where time and the temperature of the reactions were measured, and characterized by XRD and measuring its surface area. The biodiesel was obtained from methyl and ethyl esterification of acidified soybean oil and cottonseed, at a temperature of 160°C for 1 hour, molar ratio 1:15, 3% of catalyst and analyzed by chromatography. The nanoferrite has shown peaks of greater intensity corresponding to a majority crystal phase of the spinel and a surface area of 64.17m2/g. The conversion resul...
Ni0.5Zn0.5Fe2O4 catalyst was synthesized by combustion method Important reaction parameters w... more Ni0.5Zn0.5Fe2O4 catalyst was synthesized by combustion method Important reaction parameters were evaluated Transesterification reaction kinetic for soybean oil and methanol was determined Biodiesel was produced by transesterification method using Ni0.5Zn0.5Fe2O4 catalyst SUMMARY Biodiesel was successfully produced by transesterification process of soybean oil and methanol using Ni0.5Zn0.5Fe2O4 nanomagnetic catalyst. The Ni0.5Zn0.5Fe2O4 catalyst was synthesized by the combustion method and its properties were investigated using X-ray diffraction (XRD), N2 physisorption at 77 K, Fourier transform infrared analysis (FT-IR), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and a transmission electron microscopy (TEM). The performance of catalyst was investigated during transesterification reaction for FAMEs production. Fatty acid methyl esters (FAMEs) were studied by gas chromatography (GC) technique. The effect of reaction conditions such as molar ratio of methanol/soybean oil, catalyst amount, reaction temperature and reaction time on FAMEs yield were also evaluated. The biodiesel yield of 92.1 % was obtained under the following reaction conditions: 9:1 of methanol/soybean oil molar ratio and, 2 % of catalyst loading at 180 °C in 3 h. Furthermore, the energy of activation (Ea) was 67.4 kJ.mo1-1 and the pre-exponential factor (ko) was 8.35×10 4 L mol −1 min −1 determined using Arrhenius equation.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
This research proposes to obtain iron spinels MFe 2 O 4 , and their hybrids MFe 2 O 4 @SiO 2 and ... more This research proposes to obtain iron spinels MFe 2 O 4 , and their hybrids MFe 2 O 4 @SiO 2 and MFe 2 O 4 @SiO 2 / chitosan (M = Cu, Ni, Co, Mn e Fe) from the surface modification with (3-aminopropyl)trimethoxysilane agent and functionalization with chitosan, and then evaluate them as to their structure, morphology, magnetism and cytotoxicity, towards obtaining biocompatible hybrids for biological applications. The samples were analyzed by XRD, FTIR, SEM, TEM, magnetic measurements and in vitro cytotoxicity. XRD results showed that all samples presented the formation of the desired spinel major phase, with a crystallite size between 12 and 45 nm. According to the morphology and FTIR spectra of the samples, it was possible to confirm the formation of the hybrids. All samples presented soft magnetic material characteristics, exception given to the iron spinels CoFe 2 O 4 , which showed characteristic of hard magnetic material. The best results of cell viability were obtained by the CoFe 2 O 4 , MnFe 2 O 4 e Fe 3 O 4 MNPs and their hybrids.
Nanotechnology has been important in improving of the properties of the materials used in the man... more Nanotechnology has been important in improving of the properties of the materials used in the manufacture of magnetic devices, electromagnetic radiation absorbers, cell telephony, pigments and lately in catalysis in transesterification and esterification reactions to biodiesel obtaining. The objective of this work was to synthesize and characterize magnetic materials of spinel type compound of CuFe2O4, CoFe2O4, MnFe2O4, NiFe2O4 and FeFe2O4 and to check the catalytic effect on the methyl esterification reaction of soybean oil. The samples were obtained by combustion reaction and characterized by XRD, FTIR, BET and SEM. The results analysis revealed for nanoferrites the spinel phase formation and higher specific area to the sample CoFe2O4. Generally the samples presented in irregular agglomerates form. All samples were catalytically active in the esterification reaction, with the highest conversion obtained by the sample MnFe2O4 with 57%.
Magnetic catalysts are easily removed from the reaction process, thereby reducing the wastewater ... more Magnetic catalysts are easily removed from the reaction process, thereby reducing the wastewater generation. Therefore, the study proposes to evaluate the performance of the nanomagnetic catalyst Ni0.5Zn0.5Fe2O4 in the transesterification reaction of the soybean oil to produce biodiesel, varying processing conditions (temperature, molar ratio of oil:alcohol and catalyst amount) on the catalytic reaction. The catalyst was synthesized by combustion reaction and characterized by XRD, BET, magnetic measurements and gas chromatography. The results revealed the inverse spinel phase formation, type B(AB)2O4, with isotherm profile classified as type V with hysteresis loop of type 3 (H3), and surface area of 48.39 m2g-1. The magnetic hysteresis curve showed a characteristic behavior of soft magnetic material with saturation magnetization value of 55 emu/g. Chromatographic analysis confirmed that the magnetic nanoparticles are catalytically active and that the processing conditions directly...
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