Fatemeh Ravari - Academia.edu (original) (raw)

Papers by Fatemeh Ravari

ACS Omega

Development of light-harvesting properties and inhibition of photogenerated charge carrier recomb... more Development of light-harvesting properties and inhibition of photogenerated charge carrier recombination are of paramount significance in the photocatalytic process. In the present work, we described the synthesis of core−shell heterostructures, which are composed of titanium oxide (TiO 2) and cerium oxide (CeO 2) deposited on a reduced graphene oxide (rGO) surface as a conductive substrate. Following the synthesis of ternary rGO-CeO 2 @TiO 2 and rGO-TiO 2 @CeO 2 nanostructures, their photocatalytic activity was investigated toward the degradation of rhodamine B dye as an organic pollutant under UV light irradiation. The obtained structures were characterized with high-resolution transmission electron microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer−Emmett−Teller, Xray photoelectron spectroscopy surface analysis, and UV−Vis spectroscopy. Various parameters including pH, catalyst dosage, temperature, and contact time were studied for photocatalysis optimization. Heterostructures showed considerable advantages because of their high surface area and superior photocatalytic performance. In contrast, rGO-CeO 2 @TiO 2 showed the highest photocatalytic activity, which is attributed to the more effective electron−hole separation and quick suppression of charge recombination at core−shell phases. A biological assay of the prepared heterostructure was performed to determine the cytotoxicity against breast cancer cells (MCF-7) and demonstrated a very low survival rate at 7.65% of cells at the 17.5 mg mL −1 concentration of applied photocatalyst.

Fullerenes, Nanotubes and Carbon Nanostructures, 2020

Abstract We synthesized decorated graphene oxide with CeO2 nanoparticles (CeO2-GO) hybridusing si... more Abstract We synthesized decorated graphene oxide with CeO2 nanoparticles (CeO2-GO) hybridusing silane coupling agents, then we dispersed them in the epoxy resin after optimizing it at a weight fraction %1 using differential scanning calorimetry (DSC). The structural and morphological characterization was evaluated using Fourier Transform Infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction. The thermal stability of CeO2-GO/Epoxy (CGE) and neat epoxy (NE) were studied by TGA analyses and showed that the CGE system has a good thermal stability and higher char yield comparing to the NE system. The degradation kinetic parameters for CGE matrix were computed by the Vyazovkin’s advanced isoconversional method. The master plots as model fitting was used to estimate the thermal decomposition mechanism, and the results show a good agreement between the experimental data and the F1 theoretical model. We have used electrical impedance spectroscopy (EIS) to evaluate electrical resistance of the CGE system at different percent of (CeO2-GO) nanoparticle. This research highlights that the (CeO2-GO) nanoparticleis a promising candidate for fabrication of anticorrosive coatings. Graphical abstract

Nanocomposites made by epoxies and inorganic materials have been a vital subject of research not ... more Nanocomposites made by epoxies and inorganic materials have been a vital subject of research not only due to that epoxies are one of the most important type of thermosetting resins widely used as surface coatings, adhesives, castings and laminates [1], but also owing to that epoxy–inorganic nanocomposites may offer unique properties compared with conventional epoxy-based composites because of their distinctive size, surface chemistry and topology [2]. In this study, Glycerol diglycidyl ether (GDE), and 3,3-dimethylglutaric anhydride (DGA) were carefully and homogeneously mixed, at a stoichiometric ratio, then nanoalumina (10 phr) is added to the epoxy matrix. In the last stage, the initiator was added at 0188 . 0 TEA X . Dynamic DSC scans were conducted in the temperature rang of 25-280 C at five different heating rates of 2.5, 5, 7.5, 10 and 15 min / 0 C . Experimental data was analyzed using DSC by the homogeneous reaction method in which a E

Physical Chemistry Research, 2017

The influence of cation-π interactions on the strength and nature of intramolecular O...H hydroge... more The influence of cation-π interactions on the strength and nature of intramolecular O...H hydrogen bond has been investigated by quantum chemical calculations in orthohydroxy benzaldehyde (HBA) compound. Ab initio calculations have been performed at MP2/6-311++G** level of theory. Vibrational frequencies and physical properties such as chemical potential and chemical hardness of these compounds have been systematically explored. The natural bond orbital (NBO) analysis and the Bader’s quantum theory of atoms in molecules (QTAIMs) have also been used to elucidate the interaction characteristics of these complexes. The intramolecular O...H hydrogen bond has been putted in the categories weak to medium in the investigated systems. The results obtained from calculations and the topological parameters derived from the Bader theory suggest that the strongest interaction and the highest electron density at BCP (bond critical point) are related to the Be2+-HBA complex. The HOMO–LUMO energy h...

Thermosetting materials have become increasingly important because of the wide variety of their a... more Thermosetting materials have become increasingly important because of the wide variety of their applications in the automotive, electronics, aerospace, and plastic industries and in the making of structural composites. Depending on the chemical structure of the curing agent and on conditions, it is possible to vary desired physical properties, such as toughness, chemical resistance, and mechanical properties ranging from extreme flexibility to high strength, high adhesivity, good heat resistance, and high electrical resistance. Amines and diacid anhydrides are common curing agents [1]. Glycerol diglycidyl ether (GDE) is added to the anhydride curing agent (DGA) at stoichiometric ratio and then fixed amount of nanoAl2O3 (10phr ) was incorporated into the above mixture. The mixtures were further homogenized by ultrasonic treatment for a period of 2 hours at room temperature. Finally, the initiator was added at 0188 . 0 TEA X . DSC measurements were performed on a Perkin Elmer DSC-7 di...

A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil a... more A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil and anticancer uracil's is performed using M06-2X/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels of theory. In the studied systems, the uracil's can be placed in three preferential interaction sites (A1–A3) in the vicinity of the vitamin B3. For each uracil group, three configurations corresponding to energetic local minima are obtained. Among the various hydrogen bonding sites, the A1 region of uracil's shows the strongest interactions at both levels of theory. The analyzed dimers are also stabilized by two hydrogen bonds (H-bonds). The predicted H-bonds in the formation of complexes are: O∙∙∙H-N and O(S)∙∙∙H-O. The topological properties of the electron density distribution are also analyzed in terms of the Quantum Theory of “Atoms in Molecules” (QTAIM). Furthermore, the natural bond orbital (NBO) analysis is applied to get a more precise insight about the nature of the H-bond...

In this paper, graphene oxide decorated with cerium oxide (CeO2) nanoparticles was prepared and u... more In this paper, graphene oxide decorated with cerium oxide (CeO2) nanoparticles was prepared and used as anticorrosive pigments in epoxy nanocomposite coatings. The synthesized nanoparticle was characterized by FTIR, XRD, SEM, and EDX analyses. Graphene oxide decorated with CeO2 nanoparticles was dispersed in epoxy resin by sonication. The optimum nanoparticle content of the epoxy resin was studied by differential scanning calorimetry. The anticorrosive properties of these coatings were investigated using electrochemical impedance spectroscopy method and polarization in corrosive solution. Impedance parameters showed a decrease in the coating resistance over immersion time. The results indicated that the epoxy coatings containing nanoparticles could significantly increase the corrosion resistance of composite coatings compared to those of pure epoxy, and the highest value was obtained for 1% nanocomposite coatings after 270 days of immersion. Pull-off adhesion test showed that the hi...

Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2020

In this work, the dry reforming of methane was studied using a corona and gliding discharge plasm... more In this work, the dry reforming of methane was studied using a corona and gliding discharge plasma microreactors. A chemical kinetic model was developed to describe the experimental behavior observed. The kinetic model is proposed based on the assumption that the reactant molecules CH4 or CO2 are attacked by active species produced by the plasma discharges, and the production of this active species are a function of the plasma power. The modelization allowed the prediction of the conversion of the reactants (CH4 and CO2) according to the energy transfer to the gas (). The value is characteristic of the energy cost; the lower β value indicated better efficiency. The value of CH4 was found to be 10.42 and 58.25 J and for CO2 equal to 12.24 and 27.77 J for corona and gliding discharge plasma, respectively. The kinetic model also demonstrated that the methane and carbon dioxide conversion was an exponential function of the plasma energy, and were a linear function of the input energy fo...

Journal of Molecular Graphics and Modelling, 2021

The 4-functionalized 6,6'-dimethyl-3,3'-dihydroxy-2,2'-bipyridine dyes (BP(OH)2-Rs) h... more The 4-functionalized 6,6'-dimethyl-3,3'-dihydroxy-2,2'-bipyridine dyes (BP(OH)2-Rs) have exhibited dienol and diketo emissions. The optimum geometrical structures for ground, singlet and triplet excited states are computed by DFT/B3LYP/6-31++G that showed the planarity of BP(OH)2-Rs structure. The emission spectra of the molecules are determined in the gas-phase at singlet and triplet excited states using CIS/6-31++G. The theoretical calculations are carried out for BP(OH)2-Rs to understand the impact of different substituents (R = -H (I), -Br (II), -TMS (III), -C2H (IV), -terpyridine (V) and -bodipy (diazaboraindacene) (VI)) on excited-state intramolecular proton transfer (ESIPT) in singlet and triplet excited states. Based on the calculations, the concerted diproton transfer proceeds in the triplet excited state, in which nπ* state has a significant participation in ESIPT. The spectral variation at ESIPT emission of BP(OH)2-Rs is influenced by the electron-acceptor ability of the substituents. The compound V revealed a higher spectral intensity compared to the others. From the comparison with the experimental data, the molecule V is almost planar agreed with the X-ray structure and trend variation of wavelengths. The molecule VI contains bodipy chromophore that excitation energy transfers completely from BP(OH)2 core to a bodipy substituent, leading to emission from the lowest-lying bodipy substituent, and consequently, ESIPT does not occur for this dye.

Structural Chemistry, 2020

Progress in Organic Coatings, 2019

Mesoporous silica nanoparticles were functionalized by Eriochrom Black T (ECBT) as corrosion inhi... more Mesoporous silica nanoparticles were functionalized by Eriochrom Black T (ECBT) as corrosion inhibitor. Next, the functionalized nanoparticles were loaded into the sol-gel coating in order to obtain smart coating system for Ti-Zr pretreated mild steel. Successful synthesis and functionalization of the nanoparticles were confirmed by FESEM, FTIR, and BET methods. EDS-mapping showed that the Ti-Zr pretreatment layer is mainly composed of O, Fe, Ti, and Zr atoms with uniform distribution over the surface. The SEM images revealed that the pure sol-gel coating has micro sized defects but dense silica film without any micro defects or cracks was obtained after incorporation of the functionalized nanoparticles in 0.2 wt. % concentration. The cross-sectional SEM images showed that the coatings are composed of a thin pretreatment layer and a micrometric silica layer. The average roughness of the sol-gel coating was decreased from 179 to 146 nm by incorporation of the functionalized nanoparticles due to the formation of uniform and compact silica structure. The EIS experiments were executed in 3.5 wt. % NaCl aqueous electrolyte to examine the influence of the functionalized nanoparticles on the corrosion behavior of the silane film. It was found that the resistance of the sol-gel coating against corrosion is positively influenced by incorporation of the functionalized nanoparticles so that, the Z 0.001Hz value of the coating containing functionalized nanoparticles was about 2.7 and 6.4 times higher than those obtained for the pure and unmodified silica containing coatings after 24 h immersion, respectively. Improvement of the corrosion resistance was attributed to the releasing of the ECBT molecules from the functionalized nanoparticles and their adsorption on the active corrosion sites. Uv-vis analyses showed that ECBT releasing is a pH-sensitive process implies the smart nature of the sol-gel nanocomposite. The results of the corrosion tests were confirmed by the SEM analyses at the end of the corrosion examinations.

Scientific Reports

Developing a cheap, stable and effective photocatalyst is necessary for remediation of persistent... more Developing a cheap, stable and effective photocatalyst is necessary for remediation of persistent organic pollutants. To address this challenge, we proposed a unique interfacial engineering technique and proper bandgap matching strategy to synthesize MWCNTs/ZnO/Chitosan ternary nanocomposite for effective photocatalytic application. The features of the prepared samples were determined by FESEM, TEM, EDX, elemental mapping, AFM, FT-IR, XRD, UV–Vis spectroscopy and BET surface analysis. The obtained results showed successful fabrication of synthesized nanocomposites with enhanced surface area. Degradation effect of nanostructures on methylene blue (MB) and antibacterial activity against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis) pathogenic strains were investigated. The proposed photocatalytic mechanism illustrated the electron transfer facilitated by MWCNTs/ZnO/Chitosan structure which results in spatial separation of electron–ho...

Physical Chemistry Research, 2017

The goal of this research was to study the curing behavior and biodegradability DER 736 modified ... more The goal of this research was to study the curing behavior and biodegradability DER 736 modified with epoxidized oleic acid. In this paper we demonstrate the efficient epoxidation of oleic acid with performic acid generated in situ from formic acid and hydrogen peroxide in the presence of H2SO4 as catalyst. The highest relative epoxy yield of 61% was achieved at 40 C after 10 h. DER 736 modified with epoxidized oleic acid was thermally cured using succinic anhydride as curing agent, in the presence of triethylamine. Also, degradation of new composite studied in the presence of three different loadings of epoxidized oleic acid (0, 20, and 40 wt %) with lipase from porcine pancreas in phosphate buffer. It was found that this agent caused reducing the weight of the samples in 45 days. SEM studies also revealed higher surface erosion phenomenon and structural change of the matrix with increasing epoxidized oleic acid.

Physical Chemistry Research, 2017

In this work, the dry reforming of methane was studied using a corona and glow discharge plasma m... more In this work, the dry reforming of methane was studied using a corona and glow discharge plasma microreactors. A chemical kinetic model was developed to understand the reaction better. The modelization allowed prediction of the reactants conversion according to the energy transfer to the gas (P×τ). The β value is trait of the energy cost, whatever this value was leeser indicated better efficiency. The β value of CH4 equal to 10.42 and 9.91 J and for CO2 equal to 12.24 and 15.42 J for corona and glow discharge plasma respectively, because the dissociation energy of CO2 higher than CH4. The kinetic model demonstrated that there is an exponential function between the conversion of CH4 and CO2 and plasma energy. Also, corona discharge plasma reactor with smaller CH4/CO2 ratio has higher energy efficiency for CO2 and lower for CH4.

Journal of Polymers and the Environment

DESALINATION AND WATER TREATMENT

Application of diverse adsorbents (graphene, nano-Fe 3 O 4 , nano-clay and organically modified n... more Application of diverse adsorbents (graphene, nano-Fe 3 O 4 , nano-clay and organically modified nanoclay [ONC]) in adsorbing nitrate from aqueous solution has been studied. Four adsorption isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) were applied to fit the adsorption data at equilibrium and the optimal isotherm of each adsorbent was found. Furthermore, three kinetic models (pseudo-first-order, pseudo-second-order, and intra-particle diffusion) were performed to fit the adsorption data for all of the above-mentioned adsorbents. The highest adsorbent capacity (q m) enhances from 44.64 to 243.90 mg g-1 with changing adsorbent from graphene to modified nanoclay. The sequence corresponding to q m obtained to be as the subsequent by altering the adsorbents: graphene < nano-Fe 3 O 4 < nano-clay < ONC. Comparison of the correlation coefficients corresponding to adsorption isotherms shows that fitting graphene is better than the Dubinin-Radushkevich model, however, three other adsorption procedures fit with the Langmuir model. The adsorption kinetics is studied through fitting the observed time profiles into the pseudo-first-order (PFO), pseudo-secondorder, and intra-particle diffusion (IPD) kinetic models. Adsorbing nitrate by graphene, coordinates well with the pseudo-second-order model and also with IPD model with two separated straight lines representing that two phases affect the sorption procedure. Nano-Fe 3 O 4 adsorption procedure follows both first-order and second-order models. The IPD model is completely in agreement with the adsorption by nano-clay with a straight line, representing that the sorption procedure is controlled with intra-particle diffusion. Both pseudo-second-order model and IPD model can be utilized for describing the sorption kinetics by ONC. Based on the PFO model and comparison of kinetic constant (k 1), the order of adsorption speed was graphene < nano-Fe 3 O 4 < nano-clay < ONC.

Journal of Thermal Analysis and Calorimetry

Journal of Inorganic and Organometallic Polymers and Materials

ACS Omega

Development of light-harvesting properties and inhibition of photogenerated charge carrier recomb... more Development of light-harvesting properties and inhibition of photogenerated charge carrier recombination are of paramount significance in the photocatalytic process. In the present work, we described the synthesis of core−shell heterostructures, which are composed of titanium oxide (TiO 2) and cerium oxide (CeO 2) deposited on a reduced graphene oxide (rGO) surface as a conductive substrate. Following the synthesis of ternary rGO-CeO 2 @TiO 2 and rGO-TiO 2 @CeO 2 nanostructures, their photocatalytic activity was investigated toward the degradation of rhodamine B dye as an organic pollutant under UV light irradiation. The obtained structures were characterized with high-resolution transmission electron microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer−Emmett−Teller, Xray photoelectron spectroscopy surface analysis, and UV−Vis spectroscopy. Various parameters including pH, catalyst dosage, temperature, and contact time were studied for photocatalysis optimization. Heterostructures showed considerable advantages because of their high surface area and superior photocatalytic performance. In contrast, rGO-CeO 2 @TiO 2 showed the highest photocatalytic activity, which is attributed to the more effective electron−hole separation and quick suppression of charge recombination at core−shell phases. A biological assay of the prepared heterostructure was performed to determine the cytotoxicity against breast cancer cells (MCF-7) and demonstrated a very low survival rate at 7.65% of cells at the 17.5 mg mL −1 concentration of applied photocatalyst.

Fullerenes, Nanotubes and Carbon Nanostructures, 2020

Abstract We synthesized decorated graphene oxide with CeO2 nanoparticles (CeO2-GO) hybridusing si... more Abstract We synthesized decorated graphene oxide with CeO2 nanoparticles (CeO2-GO) hybridusing silane coupling agents, then we dispersed them in the epoxy resin after optimizing it at a weight fraction %1 using differential scanning calorimetry (DSC). The structural and morphological characterization was evaluated using Fourier Transform Infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction. The thermal stability of CeO2-GO/Epoxy (CGE) and neat epoxy (NE) were studied by TGA analyses and showed that the CGE system has a good thermal stability and higher char yield comparing to the NE system. The degradation kinetic parameters for CGE matrix were computed by the Vyazovkin’s advanced isoconversional method. The master plots as model fitting was used to estimate the thermal decomposition mechanism, and the results show a good agreement between the experimental data and the F1 theoretical model. We have used electrical impedance spectroscopy (EIS) to evaluate electrical resistance of the CGE system at different percent of (CeO2-GO) nanoparticle. This research highlights that the (CeO2-GO) nanoparticleis a promising candidate for fabrication of anticorrosive coatings. Graphical abstract

Nanocomposites made by epoxies and inorganic materials have been a vital subject of research not ... more Nanocomposites made by epoxies and inorganic materials have been a vital subject of research not only due to that epoxies are one of the most important type of thermosetting resins widely used as surface coatings, adhesives, castings and laminates [1], but also owing to that epoxy–inorganic nanocomposites may offer unique properties compared with conventional epoxy-based composites because of their distinctive size, surface chemistry and topology [2]. In this study, Glycerol diglycidyl ether (GDE), and 3,3-dimethylglutaric anhydride (DGA) were carefully and homogeneously mixed, at a stoichiometric ratio, then nanoalumina (10 phr) is added to the epoxy matrix. In the last stage, the initiator was added at 0188 . 0 TEA X . Dynamic DSC scans were conducted in the temperature rang of 25-280 C at five different heating rates of 2.5, 5, 7.5, 10 and 15 min / 0 C . Experimental data was analyzed using DSC by the homogeneous reaction method in which a E

Physical Chemistry Research, 2017

The influence of cation-π interactions on the strength and nature of intramolecular O...H hydroge... more The influence of cation-π interactions on the strength and nature of intramolecular O...H hydrogen bond has been investigated by quantum chemical calculations in orthohydroxy benzaldehyde (HBA) compound. Ab initio calculations have been performed at MP2/6-311++G** level of theory. Vibrational frequencies and physical properties such as chemical potential and chemical hardness of these compounds have been systematically explored. The natural bond orbital (NBO) analysis and the Bader’s quantum theory of atoms in molecules (QTAIMs) have also been used to elucidate the interaction characteristics of these complexes. The intramolecular O...H hydrogen bond has been putted in the categories weak to medium in the investigated systems. The results obtained from calculations and the topological parameters derived from the Bader theory suggest that the strongest interaction and the highest electron density at BCP (bond critical point) are related to the Be2+-HBA complex. The HOMO–LUMO energy h...

Thermosetting materials have become increasingly important because of the wide variety of their a... more Thermosetting materials have become increasingly important because of the wide variety of their applications in the automotive, electronics, aerospace, and plastic industries and in the making of structural composites. Depending on the chemical structure of the curing agent and on conditions, it is possible to vary desired physical properties, such as toughness, chemical resistance, and mechanical properties ranging from extreme flexibility to high strength, high adhesivity, good heat resistance, and high electrical resistance. Amines and diacid anhydrides are common curing agents [1]. Glycerol diglycidyl ether (GDE) is added to the anhydride curing agent (DGA) at stoichiometric ratio and then fixed amount of nanoAl2O3 (10phr ) was incorporated into the above mixture. The mixtures were further homogenized by ultrasonic treatment for a period of 2 hours at room temperature. Finally, the initiator was added at 0188 . 0 TEA X . DSC measurements were performed on a Perkin Elmer DSC-7 di...

A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil a... more A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil and anticancer uracil's is performed using M06-2X/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels of theory. In the studied systems, the uracil's can be placed in three preferential interaction sites (A1–A3) in the vicinity of the vitamin B3. For each uracil group, three configurations corresponding to energetic local minima are obtained. Among the various hydrogen bonding sites, the A1 region of uracil's shows the strongest interactions at both levels of theory. The analyzed dimers are also stabilized by two hydrogen bonds (H-bonds). The predicted H-bonds in the formation of complexes are: O∙∙∙H-N and O(S)∙∙∙H-O. The topological properties of the electron density distribution are also analyzed in terms of the Quantum Theory of “Atoms in Molecules” (QTAIM). Furthermore, the natural bond orbital (NBO) analysis is applied to get a more precise insight about the nature of the H-bond...

In this paper, graphene oxide decorated with cerium oxide (CeO2) nanoparticles was prepared and u... more In this paper, graphene oxide decorated with cerium oxide (CeO2) nanoparticles was prepared and used as anticorrosive pigments in epoxy nanocomposite coatings. The synthesized nanoparticle was characterized by FTIR, XRD, SEM, and EDX analyses. Graphene oxide decorated with CeO2 nanoparticles was dispersed in epoxy resin by sonication. The optimum nanoparticle content of the epoxy resin was studied by differential scanning calorimetry. The anticorrosive properties of these coatings were investigated using electrochemical impedance spectroscopy method and polarization in corrosive solution. Impedance parameters showed a decrease in the coating resistance over immersion time. The results indicated that the epoxy coatings containing nanoparticles could significantly increase the corrosion resistance of composite coatings compared to those of pure epoxy, and the highest value was obtained for 1% nanocomposite coatings after 270 days of immersion. Pull-off adhesion test showed that the hi...

Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2020

In this work, the dry reforming of methane was studied using a corona and gliding discharge plasm... more In this work, the dry reforming of methane was studied using a corona and gliding discharge plasma microreactors. A chemical kinetic model was developed to describe the experimental behavior observed. The kinetic model is proposed based on the assumption that the reactant molecules CH4 or CO2 are attacked by active species produced by the plasma discharges, and the production of this active species are a function of the plasma power. The modelization allowed the prediction of the conversion of the reactants (CH4 and CO2) according to the energy transfer to the gas (). The value is characteristic of the energy cost; the lower β value indicated better efficiency. The value of CH4 was found to be 10.42 and 58.25 J and for CO2 equal to 12.24 and 27.77 J for corona and gliding discharge plasma, respectively. The kinetic model also demonstrated that the methane and carbon dioxide conversion was an exponential function of the plasma energy, and were a linear function of the input energy fo...

Journal of Molecular Graphics and Modelling, 2021

The 4-functionalized 6,6'-dimethyl-3,3'-dihydroxy-2,2'-bipyridine dyes (BP(OH)2-Rs) h... more The 4-functionalized 6,6'-dimethyl-3,3'-dihydroxy-2,2'-bipyridine dyes (BP(OH)2-Rs) have exhibited dienol and diketo emissions. The optimum geometrical structures for ground, singlet and triplet excited states are computed by DFT/B3LYP/6-31++G that showed the planarity of BP(OH)2-Rs structure. The emission spectra of the molecules are determined in the gas-phase at singlet and triplet excited states using CIS/6-31++G. The theoretical calculations are carried out for BP(OH)2-Rs to understand the impact of different substituents (R = -H (I), -Br (II), -TMS (III), -C2H (IV), -terpyridine (V) and -bodipy (diazaboraindacene) (VI)) on excited-state intramolecular proton transfer (ESIPT) in singlet and triplet excited states. Based on the calculations, the concerted diproton transfer proceeds in the triplet excited state, in which nπ* state has a significant participation in ESIPT. The spectral variation at ESIPT emission of BP(OH)2-Rs is influenced by the electron-acceptor ability of the substituents. The compound V revealed a higher spectral intensity compared to the others. From the comparison with the experimental data, the molecule V is almost planar agreed with the X-ray structure and trend variation of wavelengths. The molecule VI contains bodipy chromophore that excitation energy transfers completely from BP(OH)2 core to a bodipy substituent, leading to emission from the lowest-lying bodipy substituent, and consequently, ESIPT does not occur for this dye.

Structural Chemistry, 2020

Progress in Organic Coatings, 2019

Mesoporous silica nanoparticles were functionalized by Eriochrom Black T (ECBT) as corrosion inhi... more Mesoporous silica nanoparticles were functionalized by Eriochrom Black T (ECBT) as corrosion inhibitor. Next, the functionalized nanoparticles were loaded into the sol-gel coating in order to obtain smart coating system for Ti-Zr pretreated mild steel. Successful synthesis and functionalization of the nanoparticles were confirmed by FESEM, FTIR, and BET methods. EDS-mapping showed that the Ti-Zr pretreatment layer is mainly composed of O, Fe, Ti, and Zr atoms with uniform distribution over the surface. The SEM images revealed that the pure sol-gel coating has micro sized defects but dense silica film without any micro defects or cracks was obtained after incorporation of the functionalized nanoparticles in 0.2 wt. % concentration. The cross-sectional SEM images showed that the coatings are composed of a thin pretreatment layer and a micrometric silica layer. The average roughness of the sol-gel coating was decreased from 179 to 146 nm by incorporation of the functionalized nanoparticles due to the formation of uniform and compact silica structure. The EIS experiments were executed in 3.5 wt. % NaCl aqueous electrolyte to examine the influence of the functionalized nanoparticles on the corrosion behavior of the silane film. It was found that the resistance of the sol-gel coating against corrosion is positively influenced by incorporation of the functionalized nanoparticles so that, the Z 0.001Hz value of the coating containing functionalized nanoparticles was about 2.7 and 6.4 times higher than those obtained for the pure and unmodified silica containing coatings after 24 h immersion, respectively. Improvement of the corrosion resistance was attributed to the releasing of the ECBT molecules from the functionalized nanoparticles and their adsorption on the active corrosion sites. Uv-vis analyses showed that ECBT releasing is a pH-sensitive process implies the smart nature of the sol-gel nanocomposite. The results of the corrosion tests were confirmed by the SEM analyses at the end of the corrosion examinations.

Scientific Reports

Developing a cheap, stable and effective photocatalyst is necessary for remediation of persistent... more Developing a cheap, stable and effective photocatalyst is necessary for remediation of persistent organic pollutants. To address this challenge, we proposed a unique interfacial engineering technique and proper bandgap matching strategy to synthesize MWCNTs/ZnO/Chitosan ternary nanocomposite for effective photocatalytic application. The features of the prepared samples were determined by FESEM, TEM, EDX, elemental mapping, AFM, FT-IR, XRD, UV–Vis spectroscopy and BET surface analysis. The obtained results showed successful fabrication of synthesized nanocomposites with enhanced surface area. Degradation effect of nanostructures on methylene blue (MB) and antibacterial activity against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis) pathogenic strains were investigated. The proposed photocatalytic mechanism illustrated the electron transfer facilitated by MWCNTs/ZnO/Chitosan structure which results in spatial separation of electron–ho...

Physical Chemistry Research, 2017

The goal of this research was to study the curing behavior and biodegradability DER 736 modified ... more The goal of this research was to study the curing behavior and biodegradability DER 736 modified with epoxidized oleic acid. In this paper we demonstrate the efficient epoxidation of oleic acid with performic acid generated in situ from formic acid and hydrogen peroxide in the presence of H2SO4 as catalyst. The highest relative epoxy yield of 61% was achieved at 40 C after 10 h. DER 736 modified with epoxidized oleic acid was thermally cured using succinic anhydride as curing agent, in the presence of triethylamine. Also, degradation of new composite studied in the presence of three different loadings of epoxidized oleic acid (0, 20, and 40 wt %) with lipase from porcine pancreas in phosphate buffer. It was found that this agent caused reducing the weight of the samples in 45 days. SEM studies also revealed higher surface erosion phenomenon and structural change of the matrix with increasing epoxidized oleic acid.

Physical Chemistry Research, 2017

In this work, the dry reforming of methane was studied using a corona and glow discharge plasma m... more In this work, the dry reforming of methane was studied using a corona and glow discharge plasma microreactors. A chemical kinetic model was developed to understand the reaction better. The modelization allowed prediction of the reactants conversion according to the energy transfer to the gas (P×τ). The β value is trait of the energy cost, whatever this value was leeser indicated better efficiency. The β value of CH4 equal to 10.42 and 9.91 J and for CO2 equal to 12.24 and 15.42 J for corona and glow discharge plasma respectively, because the dissociation energy of CO2 higher than CH4. The kinetic model demonstrated that there is an exponential function between the conversion of CH4 and CO2 and plasma energy. Also, corona discharge plasma reactor with smaller CH4/CO2 ratio has higher energy efficiency for CO2 and lower for CH4.

Journal of Polymers and the Environment

DESALINATION AND WATER TREATMENT

Application of diverse adsorbents (graphene, nano-Fe 3 O 4 , nano-clay and organically modified n... more Application of diverse adsorbents (graphene, nano-Fe 3 O 4 , nano-clay and organically modified nanoclay [ONC]) in adsorbing nitrate from aqueous solution has been studied. Four adsorption isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) were applied to fit the adsorption data at equilibrium and the optimal isotherm of each adsorbent was found. Furthermore, three kinetic models (pseudo-first-order, pseudo-second-order, and intra-particle diffusion) were performed to fit the adsorption data for all of the above-mentioned adsorbents. The highest adsorbent capacity (q m) enhances from 44.64 to 243.90 mg g-1 with changing adsorbent from graphene to modified nanoclay. The sequence corresponding to q m obtained to be as the subsequent by altering the adsorbents: graphene < nano-Fe 3 O 4 < nano-clay < ONC. Comparison of the correlation coefficients corresponding to adsorption isotherms shows that fitting graphene is better than the Dubinin-Radushkevich model, however, three other adsorption procedures fit with the Langmuir model. The adsorption kinetics is studied through fitting the observed time profiles into the pseudo-first-order (PFO), pseudo-secondorder, and intra-particle diffusion (IPD) kinetic models. Adsorbing nitrate by graphene, coordinates well with the pseudo-second-order model and also with IPD model with two separated straight lines representing that two phases affect the sorption procedure. Nano-Fe 3 O 4 adsorption procedure follows both first-order and second-order models. The IPD model is completely in agreement with the adsorption by nano-clay with a straight line, representing that the sorption procedure is controlled with intra-particle diffusion. Both pseudo-second-order model and IPD model can be utilized for describing the sorption kinetics by ONC. Based on the PFO model and comparison of kinetic constant (k 1), the order of adsorption speed was graphene < nano-Fe 3 O 4 < nano-clay < ONC.

Journal of Thermal Analysis and Calorimetry

Journal of Inorganic and Organometallic Polymers and Materials