Azza El Maghraby - Academia.edu (original) (raw)

Papers by Azza El Maghraby

Carbon Letters, 2021

The implanted electronic devices require a stable, continuous, and long-lasting energy source to ... more The implanted electronic devices require a stable, continuous, and long-lasting energy source to function correctly. These devices are powered by alkaline batteries and lithium ions. When used in implantable or wearable devices, these batteries can pose a threat to human health and the environment. Because of these factors, implantable and wearable devices using enzyme biofuel cells (EBFCs) are receiving a lot of attention. These EBFCs use human physiological fluid to provide long-term control for these devices. Carbon nanomaterials have successfully been demonstrated in enzymatic biofuel cells to improve applications by increasing current and power density; they have the potential to enhance EBFC efficiency. This review summarizes the fundamental process of EBFC compounds based on carbon nanomaterials before delving into the most recent advancements that have been tested and used as implantable and wearable self-power sources.

Molecules, 2021

Electrospun carbon nanofibers (CNFs), which were modified with hydroxyapatite, were fabricated to... more Electrospun carbon nanofibers (CNFs), which were modified with hydroxyapatite, were fabricated to be used as a substrate for bone cell proliferation. The CNFs were derived from electrospun polyacrylonitrile (PAN) nanofibers after two steps of heat treatment: stabilization and carbonization. Carbon nanofibrous (CNF)/hydroxyapatite (HA) nanocomposites were prepared by two different methods; one of them being modification during electrospinning (CNF-8HA) and the second method being hydrothermal modification after carbonization (CNF-8HA; hydrothermally) to be used as a platform for bone tissue engineering. The biological investigations were performed using in-vitro cell counting, WST cell viability and cell morphology after three and seven days. L929 mouse fibroblasts were found to be more viable on the hydrothermally-modified CNF scaffolds than on the unmodified CNF scaffolds. The biological characterizations of the synthesized CNF/HA nanofibrous composites indicated higher capability ...

Molecules, Mar 11, 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

DESALINATION AND WATER TREATMENT, 2021

This article was originally published with an error in the affiliations of Azza El-Maghrabhy and ... more This article was originally published with an error in the affiliations of Azza El-Maghrabhy and Nazly Hassan This version has been corrected.

Journal of Bone Research, 2017

Critical size bone defects are orthopedic defects that will not heal without intervention or that... more Critical size bone defects are orthopedic defects that will not heal without intervention or that will not completely heal over the natural life time of the animal. Although bone generally has the ability to regenerate completely however, critical defects need sort of scaffold to do so. In the current study, we proposed a method to get a Carbon NanoFibrous (CNFs) / Hydroxyapatite (HA) bioactive scaffold. The CNF nonwoven fabrics were obtained by the use of the electrospinning process of the polymeric solution of Poly Acrylonitrile (PAN) and next thermal treatment of both stabilization and carbonization processes, then the CNFs membranes were functionalized by (6.8 wt.%) HA by the hydrothermal process (130ºC for 90 min). The prepared membranes were in-vitro tested for bioactivity in Simulated Body Fluid (SBF) solution and for biodegradability in Phosphate Buffer Saline (PBS) solution. We have successfully prepared a bioactive and biodegradable membrane by immersing it in SBF and PBS solutions respectively for 14 days, where a bioactive layer of Hydroxy-Carbonated Apatite (HCA) was found on its surface. The formed layer of HCA has been characterized by XRD, FTIR, and SEM. The biodegradability of the membranes has been characterized by FTIR, SEM, and ICP for the PBS solution after different time intervals (1, 3, 5, 7 and 14) days. The membrane of (CNF/6%HA) is more biodegradable than other membranes of (CNF, and CNF/8%HA) (Figure 1).

Materials science & engineering. C, Materials for biological applications, 2017

Critical size bone defects are orthopedic defects that will not heal without intervention or that... more Critical size bone defects are orthopedic defects that will not heal without intervention or that will not completely heal over the natural life time of the animal. Although bone generally has the ability to regenerate completely however, critical defects require some sort of scaffold to do so. In the current study we proposed a method to obtain a carbon nanofibrous/Hydroxyapatite (HA) bioactive scaffold. The carbon nanofibrous (CNF) nonwoven fabrics were obtained by the use of the electrospinning process of the polymeric solution of poly acrylonitrile "PAN" and subsequent stabilization and carbonization processes. The CNFs sheets were functionalized by both hydroxyapatite (HA) and bovine serum albumin (BSA). The HA was added to the electrospun solution, but in case of (BSA), it was adsorbed after the carbonization process. The changes in the properties taking place in the precursor sheets were investigated using the characterization methods (SEM, FT-IR, TGA and EDX). The ...

Bulletin of Materials Science, 2018

A novel injectable composite hydrogel based on chitosan and poly(3-hydroxybutyrate-co-3-hydroxyva... more A novel injectable composite hydrogel based on chitosan and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) reinforced with nanohydroxyapatite particles was synthesized. The chemical structure and morphology of the composite hydrogel were characterized. The composite hydrogel porosity, swelling, mechanical properties, viscoelasticity and in vitro biodegradation were also examined. Compared with the non-reinforced hydrogel, the composite hydrogel showed increased compressive strength, elastic modulus, viscous modulus, stiffness and had shear-thinning behaviour proving the injectability of the system. Swelling and biodegradation studies revealed that the composite scaffold possesses proper hydrophilicity and biodegradability. These properties make this composite hydrogel a promising injectable scaffold for bone regeneration.

Journal of Applied Polymer Science, 2003

Gelatin is a natural macromolecular protein. It contains a wide variety of amino acids in its pol... more Gelatin is a natural macromolecular protein. It contains a wide variety of amino acids in its polymer structure, and it is colorless to yellowish, water-soluble, and tasteless. It is used as a dispersing agent, sizing medium, and coating for photographic films and in pharmaceutical formulations. In this study, biodegradable mulching, based on waste gelatin from pharmaceutical gelatin scraps (derived from pharmaceutical soft gelatin capsule production), was formulated via the casting of water solutions or suspensions into flexible and consistent films. Gelatin was blended with synthetic materials such as poly(vinyl alcohol) and other natural wastes such as sugar cane bagasse and sawdust. To all formulations, 2,4-dichlorophenoxy acetic acid (2,4-D) was added as a herbicide. The morphology and mechanical properties of the samples were investigated with scanning electron microscopy and tensile testing, respectively. The results showed that the produced films had controlled-release properties. The effects of various additives and crosslinking on the films and the release of the herbicide 2,4-D from the films were also investigated. The introduction of synthetic and natural additives reduced the release rate of 2,4-D.

Abstr Biodiesel has become more attractive recently because of its environmental benefits and the... more Abstr Biodiesel has become more attractive recently because of its environmental benefits and the fact that it is made from renewable resources. The most common way to produce biodiesel is through transesterification. In spite of the many advantages of biodiesel, it is not yet commercialized all over the world. The major problem is the cost of the raw material. Waste cooking oil is a promising alternative to vegetable oil due to its reduced cost. Biodiesel was prepared via the transesterification of the esterified mixed oil, waste home domestic oil and restaurant waste cooking oil with excess alcohol using potassium hydroxide as an alkaline catalyst. The effects of reaction temperature, time and alcohol to oil ratio, catalyst type and concentration on the conversion of diesel were examined. Comparison between the analytical methods used to measure the conversion of biodiesel was evaluated and the maximum conversion of approximately 98.6 using TGA analysis and 97.6% using GC were obtained. The biodiesel conversion s as measured by TGA and GC are found to be approximately the same as the linear fit between the two data series results for R 2 value of 0.9983.

A mathematical model describing chemical kinetics of transesterification of model oil for biodies... more A mathematical model describing chemical kinetics of transesterification of model oil for biodiesel production has been developed. The model is based on the reverse mechanism of transesterification reactions and describes dynamics concentration changes of triglycerides, diglycerides, monoglycerides, biodiesel, and glycerol production. An analysis of process variables such as temperature and molar ratio model oil-methanol using response surface analysis was performed to achieve the maximum oil conversion rate to biodiesel. The reaction rate constants and activation energies were determined for all the forward and reverse reactions. The experimental results were found to fit a first-order kinetic law for the forward reaction and a second-order one for the reverse reaction. The results indicated that the rate-control step could be attributed to the surface reaction and the esterification processes can be well-depicted by the as-calculated kinetic formula in the range of the experimental conditions. A very good correlation between model simulations and experimental data was observed.

Scientific Reports

Electrospinning nanofibers have a tremendous interest in biomedical applications such as tissue e... more Electrospinning nanofibers have a tremendous interest in biomedical applications such as tissue engineering, drug administration, and wound healing because of their ability to replicate and restore the function of the natural extracellular matrix found in tissues. The study’s highlight is the electrospinning preparation and characterization of polyacrylonitrile with chicken feather keratin as an additive. In this study, keratin was extracted from chicken feather waste using an environmentally friendly method and used to reinforce polymeric nanofiber mats. Scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy were used to examine the morphology and the structure of the prepared nanofiber mats. The effect of keratin on the porosity and the tensile strength of reinforcing nanofibers is investigated. The porosity ratio of the nanofiber mats goes up from 24.52 ± 2.12 for blank polyacrylonitrile (PAN (NF)) to 90.89 ± 1.91% for polyacrylonitrile...

Advanced Materials Research

Catalytic chemical vapor deposition (CCVD) is considered as the most suitable technique for the l... more Catalytic chemical vapor deposition (CCVD) is considered as the most suitable technique for the large scale and low-cost production of carbon nanotubes (CNTs). Catalytic activity of Fe-Co, Fe-Ni and Co-Ni mixture supported on Al2O3 has been investigated in the production of carbon nanotubes (CNTs). Absolute ethanol was used as a source of carbon and nitrogen as the carrier gas. The Carbon nanotubes prepared by the catalytic decomposition of ethanol at 1173°K over iron supported alumina or silica catalysts with 5Wt% iron loading in a horizontal tube furnace under flow of nitrogen. The morphological structure of deposits CNTs were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the alumina supported catalysts more active towards CNTs formation than silica supported catalysts even with changing the percentage of metal loading (2.5% - 10%). Further investigation for alumina support with other...

Scientific Reports

Biodegradable cellulose nanocrystals hydrogels (CNCsH) were synthesized from cellulose nanocrysta... more Biodegradable cellulose nanocrystals hydrogels (CNCsH) were synthesized from cellulose nanocrystals (CNCs) which were prepared from office wastepaper (OWP) by a chemical crosslinking method using epicholorohydrin (ECH) as a cross-linker. CNCsH were tested for their swelling behavior and biodegradability and the point of zero charge had been determined. The ability of CNCsH for removing the Acid Red 8 (AR8) anionic dye from its aqueous solution was evaluated. The different parameters affecting removal of the dye, such as pH, initial concentration of dye, content of CNCs, temperature and adsorbent dosage were investigated. The optimum conditions for 68% removal efficiency were pH = 1, initial concentration of dye = 10 ppm, contact time = 105 min, CNCs content = 5% and CNCsH dosage = 0.5 g at 30 °C. The adsorption isotherms, kinetics, and thermodynamic parameters have been studied. The results showed an appropriate fit for Langmuir adsorption isotherm and pseudo-second order kinetics m...

Journal of Materials Research, 2021

Agradeço primeiramente a Deus pela proteção e sabedoria. Depois a minha família pelo amor, apoio ... more Agradeço primeiramente a Deus pela proteção e sabedoria. Depois a minha família pelo amor, apoio e pela compreensão nestesúltimos dois anos, em especialà minha mãe pela educação dada a mim, minhã irmã Cristiane pelo carinho eà minha esposa Aline pela paciência nos momentos difíceis. Agradeço ainda aos meus professores, especialmente a minha orientadora Professora Eunice, pelas contribuições e pela experiência partilhada no desenvolvimento deste trabalho. Gostaria de agradecer ao amigo Marcos Adriano da Silva Terra pelos momentos compartilhados nas idas e vindas de Cuiabá, bem como pela amizade construída para a vida inteira. Agradeço também a UFMT (Universidade Federal de Mato Grosso) pela oportunidade de cursar um mestrado. Os meus agradecimentos também a CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) pela concessão da bolsa durante todo o período de realização deste mestrado. Finalmente os meus agradecimentos aos colegas de curso pelos momentos que passamos juntos, nos tornando bem mais que colegas de mestrado, mas também amigos, e ainda a todos os profissionais da EE Dom Aquino pelos dois anos de paciência e colaboração. Muito obrigado a todos. v "A matemáticaé o alfabeto com o qual, Deus escreveu o universo." Galileu Galilei. vi Resumo Neste trabalho estuda-se uma sequência gerada através de um problema intitulado "problema dos coelhos" de Fibonacci, queé a sequência de Fibonacci (1, 1, 2, 3, 5, ...). Especificamente, faz-se uma análise de como a referida sequência está sendo abordada em alguns livros didáticos do ensino médio, um estudo de algumas propriedades e de certas aparições na natureza. Além disso, propõe-se algumas atividades que podem ser trabalhadas conjuntamente com outros conteúdos abordados no ensino médio.

DESALINATION AND WATER TREATMENT, 2021

In the original version of the article "CuO@MWCNTs nanocomposite as non-enzyme electrochemical se... more In the original version of the article "CuO@MWCNTs nanocomposite as non-enzyme electrochemical sensor for the detection of Malathion in seawater" published in vol. 236, October 2021, pp. 240-249 the affiliations of Azza El-Maghraby and Nazly Hassan were incorrect. The corrected version has subsequently been published.

A novel Graphene oxide-polyethylene glycol and polyvinyl alcohol (GO-PEG-PVA) triple network hydr... more A novel Graphene oxide-polyethylene glycol and polyvinyl alcohol (GO-PEG-PVA) triple network hydrogel were prepared to remove Copper(II) ion from its aqueous solution. The structures, morphologies, and properties of graphene oxide (GO), the composite GO-PEG-PVA and PEG-PVA were characterized using FTIR, X-ray diffraction, Scanning Electronic Microscope and Thermal Gravimetric analysis. A series of systematic batch adsorption experiments were conducted to study the adsorption property of GO, GO-PEG-PVA hydrogel and PEG-PVA hydrogel under different conditions (e.g. pH, contact time and Cu2+ ions concentration). The high adsorption capacity, easy regeneration, and effective adsorption–desorption results proved that the prepared GO-PEG-PVA composite hydrogel could be an effective adsorbent in removing Cu2+ ion from its aqueous solution. The maximum adsorption capacities were found to be 917, 900 and 423 mg g–1 for GO-PEG-PVA hydrogel, GO and PEG-PVA hydrogel, respectively at pH 5, 25 °C...

The Egyptian Journal of Chemistry, 2020

Adsorbent materials for industrial and environmental applications are the goal of seeking researc... more Adsorbent materials for industrial and environmental applications are the goal of seeking research under active investigation now. Activated carbons could be obtained from the organic material after been chemically or physically treated. In Egypt, Sugarcane bagasse could be considered one of the agricultural wastes that frequently produced. In this study, the low-cost adsorbent was prepared from raw Bagasse. The batch experiment was set up to determine the effect of using the agriculture waste (sugarcane bagasse) without any modification and activated it chemically and physically on methylene blue removal. The influence of adsorbent amount, agitation rate, and temperature on the dye removal were studied. The result shows that the percentage of dye removal reached up to %99.6 when the initial dye concentration was 15 ppm, and the amount of sorbent (chemically activated) was 0.3 g at room temperature. The adsorption kinetics and isotherms for the removal of methylene blue were represe...

Materials science & engineering. C, Materials for biological applications, 2017

Critical size bone defects are orthopedic defects that will not heal without intervention or that... more Critical size bone defects are orthopedic defects that will not heal without intervention or that will not completely heal over the natural life time of the animal. Although bone generally has the ability to regenerate completely however, critical defects require some sort of scaffold to do so. In the current study we proposed a method to obtain a carbon nanofibrous/Hydroxyapatite (HA) bioactive scaffold. The carbon nanofibrous (CNF) nonwoven fabrics were obtained by the use of the electrospinning process of the polymeric solution of poly acrylonitrile "PAN" and subsequent stabilization and carbonization processes. The CNFs sheets were functionalized by both hydroxyapatite (HA) and bovine serum albumin (BSA). The HA was added to the electrospun solution, but in case of (BSA), it was adsorbed after the carbonization process. The changes in the properties taking place in the precursor sheets were investigated using the characterization methods (SEM, FT-IR, TGA and EDX). The ...

Carbon i s d ense as well as porous solid f orm used i n a variety of applications. Activated car... more Carbon i s d ense as well as porous solid f orm used i n a variety of applications. Activated carbons are made through pyrolysis and act ivation ca rbonaceous natural as well as synthetic pr ecursors. The preparation of activated car bon f rom agricultural waste c ould i ncrease e conomic r eturn a nd r educe pollution. Barley straw have been used as a raw material to pr oduce activated carbon. The adsorption capacity was demonstrated by the isotherms of Methylene blue from aqueous solution f or t he prepared activated carbon. The st udy investigates t he remo val of Methylene blue dye f rom simulated water. The effects of different system variables, adsorbent dosage, initial dye concentration , pH and c ontact time were studied. The results showe d t hat as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly. Higher adsorption percentages were observed at l ower co ncentrations of Methylene blue. Optimum pH value for dy e a dsorption was d...

Carbon Letters, 2021

The implanted electronic devices require a stable, continuous, and long-lasting energy source to ... more The implanted electronic devices require a stable, continuous, and long-lasting energy source to function correctly. These devices are powered by alkaline batteries and lithium ions. When used in implantable or wearable devices, these batteries can pose a threat to human health and the environment. Because of these factors, implantable and wearable devices using enzyme biofuel cells (EBFCs) are receiving a lot of attention. These EBFCs use human physiological fluid to provide long-term control for these devices. Carbon nanomaterials have successfully been demonstrated in enzymatic biofuel cells to improve applications by increasing current and power density; they have the potential to enhance EBFC efficiency. This review summarizes the fundamental process of EBFC compounds based on carbon nanomaterials before delving into the most recent advancements that have been tested and used as implantable and wearable self-power sources.

Molecules, 2021

Electrospun carbon nanofibers (CNFs), which were modified with hydroxyapatite, were fabricated to... more Electrospun carbon nanofibers (CNFs), which were modified with hydroxyapatite, were fabricated to be used as a substrate for bone cell proliferation. The CNFs were derived from electrospun polyacrylonitrile (PAN) nanofibers after two steps of heat treatment: stabilization and carbonization. Carbon nanofibrous (CNF)/hydroxyapatite (HA) nanocomposites were prepared by two different methods; one of them being modification during electrospinning (CNF-8HA) and the second method being hydrothermal modification after carbonization (CNF-8HA; hydrothermally) to be used as a platform for bone tissue engineering. The biological investigations were performed using in-vitro cell counting, WST cell viability and cell morphology after three and seven days. L929 mouse fibroblasts were found to be more viable on the hydrothermally-modified CNF scaffolds than on the unmodified CNF scaffolds. The biological characterizations of the synthesized CNF/HA nanofibrous composites indicated higher capability ...

Molecules, Mar 11, 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

DESALINATION AND WATER TREATMENT, 2021

This article was originally published with an error in the affiliations of Azza El-Maghrabhy and ... more This article was originally published with an error in the affiliations of Azza El-Maghrabhy and Nazly Hassan This version has been corrected.

Journal of Bone Research, 2017

Critical size bone defects are orthopedic defects that will not heal without intervention or that... more Critical size bone defects are orthopedic defects that will not heal without intervention or that will not completely heal over the natural life time of the animal. Although bone generally has the ability to regenerate completely however, critical defects need sort of scaffold to do so. In the current study, we proposed a method to get a Carbon NanoFibrous (CNFs) / Hydroxyapatite (HA) bioactive scaffold. The CNF nonwoven fabrics were obtained by the use of the electrospinning process of the polymeric solution of Poly Acrylonitrile (PAN) and next thermal treatment of both stabilization and carbonization processes, then the CNFs membranes were functionalized by (6.8 wt.%) HA by the hydrothermal process (130ºC for 90 min). The prepared membranes were in-vitro tested for bioactivity in Simulated Body Fluid (SBF) solution and for biodegradability in Phosphate Buffer Saline (PBS) solution. We have successfully prepared a bioactive and biodegradable membrane by immersing it in SBF and PBS solutions respectively for 14 days, where a bioactive layer of Hydroxy-Carbonated Apatite (HCA) was found on its surface. The formed layer of HCA has been characterized by XRD, FTIR, and SEM. The biodegradability of the membranes has been characterized by FTIR, SEM, and ICP for the PBS solution after different time intervals (1, 3, 5, 7 and 14) days. The membrane of (CNF/6%HA) is more biodegradable than other membranes of (CNF, and CNF/8%HA) (Figure 1).

Materials science & engineering. C, Materials for biological applications, 2017

Critical size bone defects are orthopedic defects that will not heal without intervention or that... more Critical size bone defects are orthopedic defects that will not heal without intervention or that will not completely heal over the natural life time of the animal. Although bone generally has the ability to regenerate completely however, critical defects require some sort of scaffold to do so. In the current study we proposed a method to obtain a carbon nanofibrous/Hydroxyapatite (HA) bioactive scaffold. The carbon nanofibrous (CNF) nonwoven fabrics were obtained by the use of the electrospinning process of the polymeric solution of poly acrylonitrile "PAN" and subsequent stabilization and carbonization processes. The CNFs sheets were functionalized by both hydroxyapatite (HA) and bovine serum albumin (BSA). The HA was added to the electrospun solution, but in case of (BSA), it was adsorbed after the carbonization process. The changes in the properties taking place in the precursor sheets were investigated using the characterization methods (SEM, FT-IR, TGA and EDX). The ...

Bulletin of Materials Science, 2018

A novel injectable composite hydrogel based on chitosan and poly(3-hydroxybutyrate-co-3-hydroxyva... more A novel injectable composite hydrogel based on chitosan and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) reinforced with nanohydroxyapatite particles was synthesized. The chemical structure and morphology of the composite hydrogel were characterized. The composite hydrogel porosity, swelling, mechanical properties, viscoelasticity and in vitro biodegradation were also examined. Compared with the non-reinforced hydrogel, the composite hydrogel showed increased compressive strength, elastic modulus, viscous modulus, stiffness and had shear-thinning behaviour proving the injectability of the system. Swelling and biodegradation studies revealed that the composite scaffold possesses proper hydrophilicity and biodegradability. These properties make this composite hydrogel a promising injectable scaffold for bone regeneration.

Journal of Applied Polymer Science, 2003

Gelatin is a natural macromolecular protein. It contains a wide variety of amino acids in its pol... more Gelatin is a natural macromolecular protein. It contains a wide variety of amino acids in its polymer structure, and it is colorless to yellowish, water-soluble, and tasteless. It is used as a dispersing agent, sizing medium, and coating for photographic films and in pharmaceutical formulations. In this study, biodegradable mulching, based on waste gelatin from pharmaceutical gelatin scraps (derived from pharmaceutical soft gelatin capsule production), was formulated via the casting of water solutions or suspensions into flexible and consistent films. Gelatin was blended with synthetic materials such as poly(vinyl alcohol) and other natural wastes such as sugar cane bagasse and sawdust. To all formulations, 2,4-dichlorophenoxy acetic acid (2,4-D) was added as a herbicide. The morphology and mechanical properties of the samples were investigated with scanning electron microscopy and tensile testing, respectively. The results showed that the produced films had controlled-release properties. The effects of various additives and crosslinking on the films and the release of the herbicide 2,4-D from the films were also investigated. The introduction of synthetic and natural additives reduced the release rate of 2,4-D.

Abstr Biodiesel has become more attractive recently because of its environmental benefits and the... more Abstr Biodiesel has become more attractive recently because of its environmental benefits and the fact that it is made from renewable resources. The most common way to produce biodiesel is through transesterification. In spite of the many advantages of biodiesel, it is not yet commercialized all over the world. The major problem is the cost of the raw material. Waste cooking oil is a promising alternative to vegetable oil due to its reduced cost. Biodiesel was prepared via the transesterification of the esterified mixed oil, waste home domestic oil and restaurant waste cooking oil with excess alcohol using potassium hydroxide as an alkaline catalyst. The effects of reaction temperature, time and alcohol to oil ratio, catalyst type and concentration on the conversion of diesel were examined. Comparison between the analytical methods used to measure the conversion of biodiesel was evaluated and the maximum conversion of approximately 98.6 using TGA analysis and 97.6% using GC were obtained. The biodiesel conversion s as measured by TGA and GC are found to be approximately the same as the linear fit between the two data series results for R 2 value of 0.9983.

A mathematical model describing chemical kinetics of transesterification of model oil for biodies... more A mathematical model describing chemical kinetics of transesterification of model oil for biodiesel production has been developed. The model is based on the reverse mechanism of transesterification reactions and describes dynamics concentration changes of triglycerides, diglycerides, monoglycerides, biodiesel, and glycerol production. An analysis of process variables such as temperature and molar ratio model oil-methanol using response surface analysis was performed to achieve the maximum oil conversion rate to biodiesel. The reaction rate constants and activation energies were determined for all the forward and reverse reactions. The experimental results were found to fit a first-order kinetic law for the forward reaction and a second-order one for the reverse reaction. The results indicated that the rate-control step could be attributed to the surface reaction and the esterification processes can be well-depicted by the as-calculated kinetic formula in the range of the experimental conditions. A very good correlation between model simulations and experimental data was observed.

Scientific Reports

Electrospinning nanofibers have a tremendous interest in biomedical applications such as tissue e... more Electrospinning nanofibers have a tremendous interest in biomedical applications such as tissue engineering, drug administration, and wound healing because of their ability to replicate and restore the function of the natural extracellular matrix found in tissues. The study’s highlight is the electrospinning preparation and characterization of polyacrylonitrile with chicken feather keratin as an additive. In this study, keratin was extracted from chicken feather waste using an environmentally friendly method and used to reinforce polymeric nanofiber mats. Scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy were used to examine the morphology and the structure of the prepared nanofiber mats. The effect of keratin on the porosity and the tensile strength of reinforcing nanofibers is investigated. The porosity ratio of the nanofiber mats goes up from 24.52 ± 2.12 for blank polyacrylonitrile (PAN (NF)) to 90.89 ± 1.91% for polyacrylonitrile...

Advanced Materials Research

Catalytic chemical vapor deposition (CCVD) is considered as the most suitable technique for the l... more Catalytic chemical vapor deposition (CCVD) is considered as the most suitable technique for the large scale and low-cost production of carbon nanotubes (CNTs). Catalytic activity of Fe-Co, Fe-Ni and Co-Ni mixture supported on Al2O3 has been investigated in the production of carbon nanotubes (CNTs). Absolute ethanol was used as a source of carbon and nitrogen as the carrier gas. The Carbon nanotubes prepared by the catalytic decomposition of ethanol at 1173°K over iron supported alumina or silica catalysts with 5Wt% iron loading in a horizontal tube furnace under flow of nitrogen. The morphological structure of deposits CNTs were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the alumina supported catalysts more active towards CNTs formation than silica supported catalysts even with changing the percentage of metal loading (2.5% - 10%). Further investigation for alumina support with other...

Scientific Reports

Biodegradable cellulose nanocrystals hydrogels (CNCsH) were synthesized from cellulose nanocrysta... more Biodegradable cellulose nanocrystals hydrogels (CNCsH) were synthesized from cellulose nanocrystals (CNCs) which were prepared from office wastepaper (OWP) by a chemical crosslinking method using epicholorohydrin (ECH) as a cross-linker. CNCsH were tested for their swelling behavior and biodegradability and the point of zero charge had been determined. The ability of CNCsH for removing the Acid Red 8 (AR8) anionic dye from its aqueous solution was evaluated. The different parameters affecting removal of the dye, such as pH, initial concentration of dye, content of CNCs, temperature and adsorbent dosage were investigated. The optimum conditions for 68% removal efficiency were pH = 1, initial concentration of dye = 10 ppm, contact time = 105 min, CNCs content = 5% and CNCsH dosage = 0.5 g at 30 °C. The adsorption isotherms, kinetics, and thermodynamic parameters have been studied. The results showed an appropriate fit for Langmuir adsorption isotherm and pseudo-second order kinetics m...

Journal of Materials Research, 2021

Agradeço primeiramente a Deus pela proteção e sabedoria. Depois a minha família pelo amor, apoio ... more Agradeço primeiramente a Deus pela proteção e sabedoria. Depois a minha família pelo amor, apoio e pela compreensão nestesúltimos dois anos, em especialà minha mãe pela educação dada a mim, minhã irmã Cristiane pelo carinho eà minha esposa Aline pela paciência nos momentos difíceis. Agradeço ainda aos meus professores, especialmente a minha orientadora Professora Eunice, pelas contribuições e pela experiência partilhada no desenvolvimento deste trabalho. Gostaria de agradecer ao amigo Marcos Adriano da Silva Terra pelos momentos compartilhados nas idas e vindas de Cuiabá, bem como pela amizade construída para a vida inteira. Agradeço também a UFMT (Universidade Federal de Mato Grosso) pela oportunidade de cursar um mestrado. Os meus agradecimentos também a CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) pela concessão da bolsa durante todo o período de realização deste mestrado. Finalmente os meus agradecimentos aos colegas de curso pelos momentos que passamos juntos, nos tornando bem mais que colegas de mestrado, mas também amigos, e ainda a todos os profissionais da EE Dom Aquino pelos dois anos de paciência e colaboração. Muito obrigado a todos. v "A matemáticaé o alfabeto com o qual, Deus escreveu o universo." Galileu Galilei. vi Resumo Neste trabalho estuda-se uma sequência gerada através de um problema intitulado "problema dos coelhos" de Fibonacci, queé a sequência de Fibonacci (1, 1, 2, 3, 5, ...). Especificamente, faz-se uma análise de como a referida sequência está sendo abordada em alguns livros didáticos do ensino médio, um estudo de algumas propriedades e de certas aparições na natureza. Além disso, propõe-se algumas atividades que podem ser trabalhadas conjuntamente com outros conteúdos abordados no ensino médio.

DESALINATION AND WATER TREATMENT, 2021

In the original version of the article "CuO@MWCNTs nanocomposite as non-enzyme electrochemical se... more In the original version of the article "CuO@MWCNTs nanocomposite as non-enzyme electrochemical sensor for the detection of Malathion in seawater" published in vol. 236, October 2021, pp. 240-249 the affiliations of Azza El-Maghraby and Nazly Hassan were incorrect. The corrected version has subsequently been published.

A novel Graphene oxide-polyethylene glycol and polyvinyl alcohol (GO-PEG-PVA) triple network hydr... more A novel Graphene oxide-polyethylene glycol and polyvinyl alcohol (GO-PEG-PVA) triple network hydrogel were prepared to remove Copper(II) ion from its aqueous solution. The structures, morphologies, and properties of graphene oxide (GO), the composite GO-PEG-PVA and PEG-PVA were characterized using FTIR, X-ray diffraction, Scanning Electronic Microscope and Thermal Gravimetric analysis. A series of systematic batch adsorption experiments were conducted to study the adsorption property of GO, GO-PEG-PVA hydrogel and PEG-PVA hydrogel under different conditions (e.g. pH, contact time and Cu2+ ions concentration). The high adsorption capacity, easy regeneration, and effective adsorption–desorption results proved that the prepared GO-PEG-PVA composite hydrogel could be an effective adsorbent in removing Cu2+ ion from its aqueous solution. The maximum adsorption capacities were found to be 917, 900 and 423 mg g–1 for GO-PEG-PVA hydrogel, GO and PEG-PVA hydrogel, respectively at pH 5, 25 °C...

The Egyptian Journal of Chemistry, 2020

Adsorbent materials for industrial and environmental applications are the goal of seeking researc... more Adsorbent materials for industrial and environmental applications are the goal of seeking research under active investigation now. Activated carbons could be obtained from the organic material after been chemically or physically treated. In Egypt, Sugarcane bagasse could be considered one of the agricultural wastes that frequently produced. In this study, the low-cost adsorbent was prepared from raw Bagasse. The batch experiment was set up to determine the effect of using the agriculture waste (sugarcane bagasse) without any modification and activated it chemically and physically on methylene blue removal. The influence of adsorbent amount, agitation rate, and temperature on the dye removal were studied. The result shows that the percentage of dye removal reached up to %99.6 when the initial dye concentration was 15 ppm, and the amount of sorbent (chemically activated) was 0.3 g at room temperature. The adsorption kinetics and isotherms for the removal of methylene blue were represe...

Materials science & engineering. C, Materials for biological applications, 2017

Critical size bone defects are orthopedic defects that will not heal without intervention or that... more Critical size bone defects are orthopedic defects that will not heal without intervention or that will not completely heal over the natural life time of the animal. Although bone generally has the ability to regenerate completely however, critical defects require some sort of scaffold to do so. In the current study we proposed a method to obtain a carbon nanofibrous/Hydroxyapatite (HA) bioactive scaffold. The carbon nanofibrous (CNF) nonwoven fabrics were obtained by the use of the electrospinning process of the polymeric solution of poly acrylonitrile "PAN" and subsequent stabilization and carbonization processes. The CNFs sheets were functionalized by both hydroxyapatite (HA) and bovine serum albumin (BSA). The HA was added to the electrospun solution, but in case of (BSA), it was adsorbed after the carbonization process. The changes in the properties taking place in the precursor sheets were investigated using the characterization methods (SEM, FT-IR, TGA and EDX). The ...

Carbon i s d ense as well as porous solid f orm used i n a variety of applications. Activated car... more Carbon i s d ense as well as porous solid f orm used i n a variety of applications. Activated carbons are made through pyrolysis and act ivation ca rbonaceous natural as well as synthetic pr ecursors. The preparation of activated car bon f rom agricultural waste c ould i ncrease e conomic r eturn a nd r educe pollution. Barley straw have been used as a raw material to pr oduce activated carbon. The adsorption capacity was demonstrated by the isotherms of Methylene blue from aqueous solution f or t he prepared activated carbon. The st udy investigates t he remo val of Methylene blue dye f rom simulated water. The effects of different system variables, adsorbent dosage, initial dye concentration , pH and c ontact time were studied. The results showe d t hat as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly. Higher adsorption percentages were observed at l ower co ncentrations of Methylene blue. Optimum pH value for dy e a dsorption was d...