Abstract In this experimental study, the unconstrained melting process of nano-enhanced phase cha... more Abstract In this experimental study, the unconstrained melting process of nano-enhanced phase change material (NePCM) in a spherical container is investigated. For this purpose, the green synthesized copper oxide nanosheets (CuO NSs) as nanomaterial and paraffin wax as phase change material (PCM) is used. The density, thermal conductivity, and viscosity of the samples were measured. The factors of interest were melt fraction (f), Grashof number (Gr), Stefan number (Ste), Nusselt number (Nu), Fourier number (Fo), wall temperature (T, 65, 75 and 85 °C) and nanomaterial mass fraction (wt., 0.00, 0.05, 0.10 and 0.20%). Melt fraction was calculated and validated with a maximum deviation below 16% by using volume shrinkage and image processing methods. Results show that, at the wall temperature of 65 °C, the melting rate of the samples are the same; also, the total melting time for all samples at 65 °C are approximately 40 min, which is 15 and 20 min more extended than the wall temperatures of 75 °C and 85 °C cases. Nu number curves clarify that in the first 5 min of the melting, pure PCM graph is upper than other curves and becomes smoother as the CuO NSs loadings increase. Finally, the melt fraction and Nusselt number correlations are developed with a combination of f, T, Fo, Ste, and Gr. These proposed correlations are valid for the range of 0.002 ≤ FoSte ≤ 0.147 and 12400 ≤ Gr ≤ 169000. Based on the general suggested correlation, the squared correlation coefficient (R2) and mean absolute error (M.A.E.) values for the melt fraction, are 0.912 and 16.4%. Also, these values for the Nu number correlation, are 0.920 and 21%, respectively.
The rising demand for guava fruit worldwide is due to its richness in vitamin C, high yielding an... more The rising demand for guava fruit worldwide is due to its richness in vitamin C, high yielding and two bearing seasons. Given the salt stress threat to guavas and the necessity of protective strategies, in the present research guava seedlings were subjected to sodium chloride (0 and 50 mM) and salicylic acid (0 and 1 mM). To ascertain a logical conclusion, the activity of antioxidant enzymes, antioxidant capacity of DPPH, ferric reducing antioxidant power, total flavonoid and phenol contents were monitored in saltexposed guava seedlings. Based on our findings, the most superoxide dismutase (87.46 µmol min −1 g −1 DW) activity, ferric reducing antioxidant power (408.82 mmol g −1 DW), DPPH scavenging activity (80.65%), flavonoid (14.15 mg QE −1 g DW) and phenol (34.02 mg GAE g −1 DW) contents were found in 50 mM NaCl-exposed plants, which were enriched by 1 mM salicylic acid. A high correlation was observed among non-enzymatic antioxidant parameters (DPPH scavenging activity, ferric reducing antioxidant power, total flavonoid content and total phenol content). In conclusion, salicylic acid improved guavas salt tolerance by increasing both enzymatic (peroxidase and superoxide dismutase) and non-enzymatic (ferric reducing antioxidant power, DPPH scavenging activity, total phenol and flavonoid contents) pathways.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Jul 1, 2007
Partial least squares (PLS) and principal component regression (PCR) have received considerable a... more Partial least squares (PLS) and principal component regression (PCR) have received considerable attention in the chemometrics for multicomponent analysis where superiority of one over another is a challenging problem yet. Considering the effect of wavelength selection, a comparison was made between PCR and PLS methods by application those to simultaneous spectrophotometric determination of diphenylamine (DPA), a compound from the third European Union list of priority pollutants, and its environmentally related products aniline and phenol. The UV absorbance spectra of the methanolic solutions of the analytes were measured in the concentration ranges of 1.0-10.0 microg mL(-1) and then subjected to PCR and PLS. The models refinement procedure and validation was performed by cross-validation. A modified changeable size moving windows strategy, where optimized the intervals between the sensors in a selected windows, was also proposed to select the more informative spectral regions for each of the analytes. It was found that wavelength selection improved the quality of predictions for both regression methods whereas more reliable results were obtained by removing of the highly collinear neighboring wavelengths. The resultant data explained that PLS produced more or less better results when whole spectral data were used but in the case of selected wavelength regions both methods produced similar results and no comments could be given about the superiority of one against another. The major difference was obtaining the higher number of factors for PCR, which is not a significant problem.
Abstract Emission fluorescence spectroscopy has an extremely restricted scope of application to a... more Abstract Emission fluorescence spectroscopy has an extremely restricted scope of application to analyze of complex mixtures since its selectivity is reduced by the extensive spectral overlap. Synchronous fluorescence spectroscopy (SFS) is a technique enables us to analyze complex mixtures with overlapped emission and/or excitation spectra. The difference of excitation and emission wavelength of compounds (interval wavelength or Δλ) is an important characteristic in SFS. Thus a multi-parameter model was constructed to predict Δλ in 63 fluorescent compounds and the regression coefficient in training set, cross validation and test set were 0.88, 0.85 and 0.91 respectively. Furthermore, the applicability and validity of model were evaluated using different statistical methods such as y-scrambling and applicability domain. It was concluded that increasing average valence connectivity, number of Al2-NH functional group and Geary autocorrelation (lag 4) with electronegative weights can lead to increasing Δλ in the fluorescent compounds. The current study obtained an insight into the structural properties of compounds effective on their Δλ as an important parameter in SFS.
This study aimed to report a one-pot, eco-friendly and room temperature procedure to prepare high... more This study aimed to report a one-pot, eco-friendly and room temperature procedure to prepare highly stable (at least 15 months) silver nanoparticles (AgNPs) using the aqueous leaf extract of Cordia myxa. The effects of different parameters, such as applied pH in the reaction mixture, amount of the leaf extract, silver ion concentrations, time of reaction and synthesis temperature, on the formation of NPs and their Surface Plasmon Resonance (SPR) spectra were studied. The characterisation of the prepared AgNPs was done using UV-Vis spectroscopy, Fourier Transform Infrared (FTIR), X-Ray Differentiation (XRD) and Transmission Electron Microscope (TEM) techniques. The shape of the synthesised AgNPs was spherical and it sized 3-10 nm with a face-centred cubic structure with SPR spectra at 410 nm. A possible reaction mechanism of AgNP formation by biomolecules of C. myxa was also introduced. The efficiency of the synthesised AgNPs as an excellent catalyst for the reduction of organic azo dyes using NaBH 4 was proved. Dose-dependent cytotoxic activity of the prepared AgNPs against SW480 and HCT116 human colon cancer cell lines was also shown using MTT assay. Furthermore, the Ferric-Reducing Antioxidant Power (FRAP) assay was utilised to confirm the antioxidant activity of NPs. Non-toxic reagents and low-cost synthesis were the main features that made these AgNPs more attractive for chemical/biomedical applications.
We demonstrate here for the first time a one step and efficient phytosynthesis of cupric oxide na... more We demonstrate here for the first time a one step and efficient phytosynthesis of cupric oxide nanoparticles (CuO NPs) using easily available Capparis spinosa leaf extract as a bio-reductant and bio-stabilizer at room temperature without the addition of any harmful and expensive reagent and solvents. The effect of pH of the reaction, the leaf extract quantity, concentrations of the copper precursor, temperature, and reaction time were also studied in order to control over the particle size and stability. The synthesized CuO NPs at the optimum condition was characterized through UV-Vis spectroscopy, TEM and FT-IR spectroscopy. The surface plasmon resonance (SPR) of the biosynthesized CuO NPs centered at λ max 408. The FT-IR analysis demonstrates the role of phyto-compounds in the capping of the formed nanoparticles. TEM images clarified the spherical shape of the as-prepared nanoparticles with 21 to 58 nm in size and XRD analysis clarified the monoclinic phase of formed CuO NPs. Also, as a novel work, we display a colorimetric detection ability of as-synthesized CuO NPs (without surface functionalization or modification) respect to Fe 2+ and Fe 3+ in aqueous solution. Under the optimized conditions, a good linear relationship (R 2 = 0.9954, R 2 = 0.9903 for Fe 2+ and Fe 3+ , respectively) were obtained between the absorbance at 500 nm and the concentration of iron ions with a limit of quantification 0.084 ppm and 0.12 ppm for Fe 2+ and Fe 3+ , respectively. A remarkable feature of this first reported the colorimetric detection of iron ions based on the green synthesized CuO NPs is a simple and fast operation with high selectivity to Fe 2+ and Fe 3+ over other tested metal ions.
The last decade has seen a remarkable detonation in modifying chemical processes for nanomaterial... more The last decade has seen a remarkable detonation in modifying chemical processes for nanomaterial synthesis to make them 'green'. Owing to the unique properties of nanomaterial and with regard to environmental issues, in this study, a new alternative and fast eco-friendly approach for the synthesis of copper oxide nanosheets (CuO-NSs) using Terminalia catappa (Indian almond) leaf extract as a renewable and non-toxic reducing agent and efficient stabilizer was reported. It is noteworthy to mention that the present fabrication process can open up the possibility of fast, low cost and high efficiency synthesis of CuO nanostructures with an interesting morphology of nanosheets at ambient temperature and pressure. Optimization of important factors such as pH, quantity of leaf extract, copper precursor concentration, incubation time and temperature on the formation of CuO-NSs were investigated. The formation of bioreduced CuO-NSs was certified by UV-Vis spectroscopy, XRD, TEM analysis and FT-IR spectroscopy. Due to good stability, and excellent catalytic activity of the synthesized CuO-NSs, they are exerted to degrade of MB dye in water as a model color pollutant in the presence of NaBH 4 at room temperature. Furthermore, color properties of CuO nanostructures aid us to apply
A simple analytical method based on the second-order calibration of the pH gradient spectrophotom... more A simple analytical method based on the second-order calibration of the pH gradient spectrophotometric data was developed for assay of carminic acid (CA) in human plasma and orange juice over the concentration range of 1.5-14.0microM. The multi-way data analysis method was coupled with standard addition to encounter the significant effects of plasma and juices matrices on the acid-base behavior and UV-vis. absorbance spectra of CA. Thus, the standard addition three-way calibration data of plasma or fruit juices samples were analyzed by parallel factor analysis (PARAFAC) and the concentration related scores were used to derive a standard addition plot such as one obtained in univariate standard addition method. The number of PARAFAC components was obtained utilizing different criteria such as core consistency and residual errors through pf-test implementation. The applicability of the proposed method was evaluated by analysis of human plasma and fruit juices spiked with different levels of standard CA solutions. The results confirmed the success of the proposed method in the analysis of pH gradient spectrophotometric data for determination of CA. The recoveries were between 86.7 and 106.7.
Journal of The Iranian Chemical Society, Nov 17, 2015
Highly stable, aqueous dispersions, and hydrophilic ionic liquid-capped silver nanoparticles with... more Highly stable, aqueous dispersions, and hydrophilic ionic liquid-capped silver nanoparticles with positive surface charge were synthesized by in situ reduction of AgNO 3 with NaBH 4 in the presence of an imidazoliumbased ionic liquid, viz., 1-dodecyl-3-methylimidazolium chloride ([C 12 mim][Cl]) at room temperature. Prepared silver nanoparticles were characterized by UV-vis spectra, transmission electron microscopy (TEM), and zeta potential. UV-visible spectrum of the aqueous medium peaked at 407 nm corresponding to the plasmon absorbance of silver nanoparticles. TEM analysis revealed the spherical shape of the particles with sizes about 9 nm and low polydispersed. The surface charge of the synthesized silver nanoparticles was determined as +5.0 mV. The ionic liquid ([C 12 mim][Cl]) capped silver nanoparticles were stable for at least 8 months.
Journal of Analytical Science and Technology, Mar 29, 2022
The first evidence of a green, single-step, and additive-free process for the fabrication of silv... more The first evidence of a green, single-step, and additive-free process for the fabrication of silver/silver chloride nanoparticles (Ag/AgCl NPs) by fruit extract of Syzygium cumini (S. cumini) without the usage of any stabilizer and halide source was provided. The formation of nanoparticles was optimized to control the shape, size, and stability via various pHs of the reaction mixture, the quantity of fruit extract, temperature, concentrations of silver ion, and reaction time. The optimal conditions were determined: pH = 7.0, the quantity of the leaf extract = 3.0 mL, silver ion concentration = 1.0 mM, temperature = 60 °C, and incubation time = 40 min. As an application in colorimetric sensing, the ability of the prepared Ag/AgCl NPs to sense clindamycin and Fe 3+ ion in an aqueous medium was investigated. The SPR band and color of the solution of Ag/AgCl NPs undergo dramatic changes in exposure to clindamycin with new SPR peaks appearing at 500 nm, accompanied by a color change from yellow to pink due to the aggregation of NPs. Under the optimized pH of 3.0, this sensor was shown a linear dynamic range from 10.0 to 100.0 µM with a LOD of 1.2 µM and good linear relationships (R 2 = 0.99) for clindamycin. On the other hand, the quenching of the SPR peak at 412 nm was used to monitor the Fe 3+ ions with wide linear ranges of 10.0-350.0 µM under the optimized pH (pH = 9) with a LOD of 5.6 µM. In addition, the proposed sensor displayed applicability in the real sample containing clindamycin (in capsules and injection ampoules) and Fe 3+ ions (in water samples) detection.
Iranian Journal of Science and Technology-Transactions of Mechanical Engineering, Feb 20, 2018
A simple, fast and one-pot synthesis procedure based on the bio-reduction ability of an algal ext... more A simple, fast and one-pot synthesis procedure based on the bio-reduction ability of an algal extract solution has been used to produce silver nanoparticles (AgNPs). The obtained colloids have been characterized by UV–Vis, TEM and XRD. Then, the thermal conductivity of the nanofluids containing 0.2, 0.4, and 0.6 wt% AgNP synthesized using Sargassum Angostifolium in deionized water was measured in the range of 25–85 °C. The thermal conductivity increases with increasing the temperature and particle concentrations. A maximum detraction and enhancement of 33% at 0.2 wt% and 25 °C and 31% at 0.6 wt% and 85 °C were observed. Silver–water nanofluid for each concentration has critical temperature of 51, 49 and 47 °C for mass fraction percentage of 0.2, 0.4 and 0.6, respectively. There is a decrease in thermal conductivity value below critical point of temperature so adding nanoparticle for application below these points is not recommended. The measurement of the thermal conductivity of this new kind of nanofluid showed that it is an ideal fluid for heat transfer because of great value in synthesizing nanoparticles with well-controlled sizes.
Abstract In this experimental study, the unconstrained melting process of nano-enhanced phase cha... more Abstract In this experimental study, the unconstrained melting process of nano-enhanced phase change material (NePCM) in a spherical container is investigated. For this purpose, the green synthesized copper oxide nanosheets (CuO NSs) as nanomaterial and paraffin wax as phase change material (PCM) is used. The density, thermal conductivity, and viscosity of the samples were measured. The factors of interest were melt fraction (f), Grashof number (Gr), Stefan number (Ste), Nusselt number (Nu), Fourier number (Fo), wall temperature (T, 65, 75 and 85 °C) and nanomaterial mass fraction (wt., 0.00, 0.05, 0.10 and 0.20%). Melt fraction was calculated and validated with a maximum deviation below 16% by using volume shrinkage and image processing methods. Results show that, at the wall temperature of 65 °C, the melting rate of the samples are the same; also, the total melting time for all samples at 65 °C are approximately 40 min, which is 15 and 20 min more extended than the wall temperatures of 75 °C and 85 °C cases. Nu number curves clarify that in the first 5 min of the melting, pure PCM graph is upper than other curves and becomes smoother as the CuO NSs loadings increase. Finally, the melt fraction and Nusselt number correlations are developed with a combination of f, T, Fo, Ste, and Gr. These proposed correlations are valid for the range of 0.002 ≤ FoSte ≤ 0.147 and 12400 ≤ Gr ≤ 169000. Based on the general suggested correlation, the squared correlation coefficient (R2) and mean absolute error (M.A.E.) values for the melt fraction, are 0.912 and 16.4%. Also, these values for the Nu number correlation, are 0.920 and 21%, respectively.
The rising demand for guava fruit worldwide is due to its richness in vitamin C, high yielding an... more The rising demand for guava fruit worldwide is due to its richness in vitamin C, high yielding and two bearing seasons. Given the salt stress threat to guavas and the necessity of protective strategies, in the present research guava seedlings were subjected to sodium chloride (0 and 50 mM) and salicylic acid (0 and 1 mM). To ascertain a logical conclusion, the activity of antioxidant enzymes, antioxidant capacity of DPPH, ferric reducing antioxidant power, total flavonoid and phenol contents were monitored in saltexposed guava seedlings. Based on our findings, the most superoxide dismutase (87.46 µmol min −1 g −1 DW) activity, ferric reducing antioxidant power (408.82 mmol g −1 DW), DPPH scavenging activity (80.65%), flavonoid (14.15 mg QE −1 g DW) and phenol (34.02 mg GAE g −1 DW) contents were found in 50 mM NaCl-exposed plants, which were enriched by 1 mM salicylic acid. A high correlation was observed among non-enzymatic antioxidant parameters (DPPH scavenging activity, ferric reducing antioxidant power, total flavonoid content and total phenol content). In conclusion, salicylic acid improved guavas salt tolerance by increasing both enzymatic (peroxidase and superoxide dismutase) and non-enzymatic (ferric reducing antioxidant power, DPPH scavenging activity, total phenol and flavonoid contents) pathways.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Jul 1, 2007
Partial least squares (PLS) and principal component regression (PCR) have received considerable a... more Partial least squares (PLS) and principal component regression (PCR) have received considerable attention in the chemometrics for multicomponent analysis where superiority of one over another is a challenging problem yet. Considering the effect of wavelength selection, a comparison was made between PCR and PLS methods by application those to simultaneous spectrophotometric determination of diphenylamine (DPA), a compound from the third European Union list of priority pollutants, and its environmentally related products aniline and phenol. The UV absorbance spectra of the methanolic solutions of the analytes were measured in the concentration ranges of 1.0-10.0 microg mL(-1) and then subjected to PCR and PLS. The models refinement procedure and validation was performed by cross-validation. A modified changeable size moving windows strategy, where optimized the intervals between the sensors in a selected windows, was also proposed to select the more informative spectral regions for each of the analytes. It was found that wavelength selection improved the quality of predictions for both regression methods whereas more reliable results were obtained by removing of the highly collinear neighboring wavelengths. The resultant data explained that PLS produced more or less better results when whole spectral data were used but in the case of selected wavelength regions both methods produced similar results and no comments could be given about the superiority of one against another. The major difference was obtaining the higher number of factors for PCR, which is not a significant problem.
Abstract Emission fluorescence spectroscopy has an extremely restricted scope of application to a... more Abstract Emission fluorescence spectroscopy has an extremely restricted scope of application to analyze of complex mixtures since its selectivity is reduced by the extensive spectral overlap. Synchronous fluorescence spectroscopy (SFS) is a technique enables us to analyze complex mixtures with overlapped emission and/or excitation spectra. The difference of excitation and emission wavelength of compounds (interval wavelength or Δλ) is an important characteristic in SFS. Thus a multi-parameter model was constructed to predict Δλ in 63 fluorescent compounds and the regression coefficient in training set, cross validation and test set were 0.88, 0.85 and 0.91 respectively. Furthermore, the applicability and validity of model were evaluated using different statistical methods such as y-scrambling and applicability domain. It was concluded that increasing average valence connectivity, number of Al2-NH functional group and Geary autocorrelation (lag 4) with electronegative weights can lead to increasing Δλ in the fluorescent compounds. The current study obtained an insight into the structural properties of compounds effective on their Δλ as an important parameter in SFS.
This study aimed to report a one-pot, eco-friendly and room temperature procedure to prepare high... more This study aimed to report a one-pot, eco-friendly and room temperature procedure to prepare highly stable (at least 15 months) silver nanoparticles (AgNPs) using the aqueous leaf extract of Cordia myxa. The effects of different parameters, such as applied pH in the reaction mixture, amount of the leaf extract, silver ion concentrations, time of reaction and synthesis temperature, on the formation of NPs and their Surface Plasmon Resonance (SPR) spectra were studied. The characterisation of the prepared AgNPs was done using UV-Vis spectroscopy, Fourier Transform Infrared (FTIR), X-Ray Differentiation (XRD) and Transmission Electron Microscope (TEM) techniques. The shape of the synthesised AgNPs was spherical and it sized 3-10 nm with a face-centred cubic structure with SPR spectra at 410 nm. A possible reaction mechanism of AgNP formation by biomolecules of C. myxa was also introduced. The efficiency of the synthesised AgNPs as an excellent catalyst for the reduction of organic azo dyes using NaBH 4 was proved. Dose-dependent cytotoxic activity of the prepared AgNPs against SW480 and HCT116 human colon cancer cell lines was also shown using MTT assay. Furthermore, the Ferric-Reducing Antioxidant Power (FRAP) assay was utilised to confirm the antioxidant activity of NPs. Non-toxic reagents and low-cost synthesis were the main features that made these AgNPs more attractive for chemical/biomedical applications.
We demonstrate here for the first time a one step and efficient phytosynthesis of cupric oxide na... more We demonstrate here for the first time a one step and efficient phytosynthesis of cupric oxide nanoparticles (CuO NPs) using easily available Capparis spinosa leaf extract as a bio-reductant and bio-stabilizer at room temperature without the addition of any harmful and expensive reagent and solvents. The effect of pH of the reaction, the leaf extract quantity, concentrations of the copper precursor, temperature, and reaction time were also studied in order to control over the particle size and stability. The synthesized CuO NPs at the optimum condition was characterized through UV-Vis spectroscopy, TEM and FT-IR spectroscopy. The surface plasmon resonance (SPR) of the biosynthesized CuO NPs centered at λ max 408. The FT-IR analysis demonstrates the role of phyto-compounds in the capping of the formed nanoparticles. TEM images clarified the spherical shape of the as-prepared nanoparticles with 21 to 58 nm in size and XRD analysis clarified the monoclinic phase of formed CuO NPs. Also, as a novel work, we display a colorimetric detection ability of as-synthesized CuO NPs (without surface functionalization or modification) respect to Fe 2+ and Fe 3+ in aqueous solution. Under the optimized conditions, a good linear relationship (R 2 = 0.9954, R 2 = 0.9903 for Fe 2+ and Fe 3+ , respectively) were obtained between the absorbance at 500 nm and the concentration of iron ions with a limit of quantification 0.084 ppm and 0.12 ppm for Fe 2+ and Fe 3+ , respectively. A remarkable feature of this first reported the colorimetric detection of iron ions based on the green synthesized CuO NPs is a simple and fast operation with high selectivity to Fe 2+ and Fe 3+ over other tested metal ions.
The last decade has seen a remarkable detonation in modifying chemical processes for nanomaterial... more The last decade has seen a remarkable detonation in modifying chemical processes for nanomaterial synthesis to make them 'green'. Owing to the unique properties of nanomaterial and with regard to environmental issues, in this study, a new alternative and fast eco-friendly approach for the synthesis of copper oxide nanosheets (CuO-NSs) using Terminalia catappa (Indian almond) leaf extract as a renewable and non-toxic reducing agent and efficient stabilizer was reported. It is noteworthy to mention that the present fabrication process can open up the possibility of fast, low cost and high efficiency synthesis of CuO nanostructures with an interesting morphology of nanosheets at ambient temperature and pressure. Optimization of important factors such as pH, quantity of leaf extract, copper precursor concentration, incubation time and temperature on the formation of CuO-NSs were investigated. The formation of bioreduced CuO-NSs was certified by UV-Vis spectroscopy, XRD, TEM analysis and FT-IR spectroscopy. Due to good stability, and excellent catalytic activity of the synthesized CuO-NSs, they are exerted to degrade of MB dye in water as a model color pollutant in the presence of NaBH 4 at room temperature. Furthermore, color properties of CuO nanostructures aid us to apply
A simple analytical method based on the second-order calibration of the pH gradient spectrophotom... more A simple analytical method based on the second-order calibration of the pH gradient spectrophotometric data was developed for assay of carminic acid (CA) in human plasma and orange juice over the concentration range of 1.5-14.0microM. The multi-way data analysis method was coupled with standard addition to encounter the significant effects of plasma and juices matrices on the acid-base behavior and UV-vis. absorbance spectra of CA. Thus, the standard addition three-way calibration data of plasma or fruit juices samples were analyzed by parallel factor analysis (PARAFAC) and the concentration related scores were used to derive a standard addition plot such as one obtained in univariate standard addition method. The number of PARAFAC components was obtained utilizing different criteria such as core consistency and residual errors through pf-test implementation. The applicability of the proposed method was evaluated by analysis of human plasma and fruit juices spiked with different levels of standard CA solutions. The results confirmed the success of the proposed method in the analysis of pH gradient spectrophotometric data for determination of CA. The recoveries were between 86.7 and 106.7.
Journal of The Iranian Chemical Society, Nov 17, 2015
Highly stable, aqueous dispersions, and hydrophilic ionic liquid-capped silver nanoparticles with... more Highly stable, aqueous dispersions, and hydrophilic ionic liquid-capped silver nanoparticles with positive surface charge were synthesized by in situ reduction of AgNO 3 with NaBH 4 in the presence of an imidazoliumbased ionic liquid, viz., 1-dodecyl-3-methylimidazolium chloride ([C 12 mim][Cl]) at room temperature. Prepared silver nanoparticles were characterized by UV-vis spectra, transmission electron microscopy (TEM), and zeta potential. UV-visible spectrum of the aqueous medium peaked at 407 nm corresponding to the plasmon absorbance of silver nanoparticles. TEM analysis revealed the spherical shape of the particles with sizes about 9 nm and low polydispersed. The surface charge of the synthesized silver nanoparticles was determined as +5.0 mV. The ionic liquid ([C 12 mim][Cl]) capped silver nanoparticles were stable for at least 8 months.
Journal of Analytical Science and Technology, Mar 29, 2022
The first evidence of a green, single-step, and additive-free process for the fabrication of silv... more The first evidence of a green, single-step, and additive-free process for the fabrication of silver/silver chloride nanoparticles (Ag/AgCl NPs) by fruit extract of Syzygium cumini (S. cumini) without the usage of any stabilizer and halide source was provided. The formation of nanoparticles was optimized to control the shape, size, and stability via various pHs of the reaction mixture, the quantity of fruit extract, temperature, concentrations of silver ion, and reaction time. The optimal conditions were determined: pH = 7.0, the quantity of the leaf extract = 3.0 mL, silver ion concentration = 1.0 mM, temperature = 60 °C, and incubation time = 40 min. As an application in colorimetric sensing, the ability of the prepared Ag/AgCl NPs to sense clindamycin and Fe 3+ ion in an aqueous medium was investigated. The SPR band and color of the solution of Ag/AgCl NPs undergo dramatic changes in exposure to clindamycin with new SPR peaks appearing at 500 nm, accompanied by a color change from yellow to pink due to the aggregation of NPs. Under the optimized pH of 3.0, this sensor was shown a linear dynamic range from 10.0 to 100.0 µM with a LOD of 1.2 µM and good linear relationships (R 2 = 0.99) for clindamycin. On the other hand, the quenching of the SPR peak at 412 nm was used to monitor the Fe 3+ ions with wide linear ranges of 10.0-350.0 µM under the optimized pH (pH = 9) with a LOD of 5.6 µM. In addition, the proposed sensor displayed applicability in the real sample containing clindamycin (in capsules and injection ampoules) and Fe 3+ ions (in water samples) detection.
Iranian Journal of Science and Technology-Transactions of Mechanical Engineering, Feb 20, 2018
A simple, fast and one-pot synthesis procedure based on the bio-reduction ability of an algal ext... more A simple, fast and one-pot synthesis procedure based on the bio-reduction ability of an algal extract solution has been used to produce silver nanoparticles (AgNPs). The obtained colloids have been characterized by UV–Vis, TEM and XRD. Then, the thermal conductivity of the nanofluids containing 0.2, 0.4, and 0.6 wt% AgNP synthesized using Sargassum Angostifolium in deionized water was measured in the range of 25–85 °C. The thermal conductivity increases with increasing the temperature and particle concentrations. A maximum detraction and enhancement of 33% at 0.2 wt% and 25 °C and 31% at 0.6 wt% and 85 °C were observed. Silver–water nanofluid for each concentration has critical temperature of 51, 49 and 47 °C for mass fraction percentage of 0.2, 0.4 and 0.6, respectively. There is a decrease in thermal conductivity value below critical point of temperature so adding nanoparticle for application below these points is not recommended. The measurement of the thermal conductivity of this new kind of nanofluid showed that it is an ideal fluid for heat transfer because of great value in synthesizing nanoparticles with well-controlled sizes.
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