The advantage of using plants in nanoparticles synthesis is that they are easily available, safe to handle and possess a broad variability of metabolites such as antioxidants, nucleotides and vitamins. The aim of this...The advantage of using plants in nanoparticles synthesis is that they are easily available, safe to handle and possess a broad variability of metabolites such as antioxidants, nucleotides and vitamins. The aim of this study was to investigate the effects of Green and Zimbro tea and also Green coconut water as a reducing and stabilizer agent in gold nanoparticle synthesis. The gold nanoparticles were characterized by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Dynamic light scattering (DLS) and Transmission electron microscopy (TEM) analysis. Their physical stability was determined using a UV-Vis spectrophotometer over several days during storage at room temperature. We observed that green chemical process to obtain gold nanoparticles did not require any external chemicals reagent for stabilization of nanoparticulate. Absorption measurements indicated that the plasmon resonance wavelength appears around 530 nm. X-ray diffracto-grams of gold nanoparticles evidenced the presence of Au-rich (fcc) phases. TEM analysis showed a homogeneous dispersion of nanoparticles and some agglomerates. Differences in size and shape of the nanoparticles were observed. Zeta potential of AuNPs synthetized in presence of Green tea was -33 mV indicating stability of the synthesized nanoparticles.展开更多
The effect of Juniperus communis (JC) extract on the inhibition of bronze corrosion in aqueous chloride solution was studied by electrochemical polarization methods. The variation of two experimental factors such as t...The effect of Juniperus communis (JC) extract on the inhibition of bronze corrosion in aqueous chloride solution was studied by electrochemical polarization methods. The variation of two experimental factors such as the chloride concentration and the temperature allows us to deduce the kinetics parameters of this process (Ea = 65.7 kJ•mol–1). Thermodynamic calculations indicated that JC adsorption on bronze surface obeyed Arrhenius adsorption isotherm and was characterized by an endothermic process (ΔH* = 54.7 kJ•mol–1).展开更多
The main objective of the present study was to model the kinetics of essential oil extraction from swelled ground juniper berries by classic hydrodistillation(HD) and microwave-assisted hydrodistillation(MAHD). A new ...The main objective of the present study was to model the kinetics of essential oil extraction from swelled ground juniper berries by classic hydrodistillation(HD) and microwave-assisted hydrodistillation(MAHD). A new phenomenological kinetic model was developed on the basis of the juniper essential oil extraction mechanism that assumed three mass transfer processes occurring simultaneously: washing, unhindered diffusion and hindered diffusion. The new model was compared to the existing kinetic models. Among the tested models,the new model had the smallest mean relative percentage deviation and the highest corrected Akaike information criterion value. In addition, that, the new model was verified for HD and MAHD of essential oils from some other plant materials. On the basis of the above-mentioned facts, the new model can be recommended for modeling the kinetics of essential oil extraction by both HD and MAHD.展开更多
文摘The advantage of using plants in nanoparticles synthesis is that they are easily available, safe to handle and possess a broad variability of metabolites such as antioxidants, nucleotides and vitamins. The aim of this study was to investigate the effects of Green and Zimbro tea and also Green coconut water as a reducing and stabilizer agent in gold nanoparticle synthesis. The gold nanoparticles were characterized by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Dynamic light scattering (DLS) and Transmission electron microscopy (TEM) analysis. Their physical stability was determined using a UV-Vis spectrophotometer over several days during storage at room temperature. We observed that green chemical process to obtain gold nanoparticles did not require any external chemicals reagent for stabilization of nanoparticulate. Absorption measurements indicated that the plasmon resonance wavelength appears around 530 nm. X-ray diffracto-grams of gold nanoparticles evidenced the presence of Au-rich (fcc) phases. TEM analysis showed a homogeneous dispersion of nanoparticles and some agglomerates. Differences in size and shape of the nanoparticles were observed. Zeta potential of AuNPs synthetized in presence of Green tea was -33 mV indicating stability of the synthesized nanoparticles.
文摘The effect of Juniperus communis (JC) extract on the inhibition of bronze corrosion in aqueous chloride solution was studied by electrochemical polarization methods. The variation of two experimental factors such as the chloride concentration and the temperature allows us to deduce the kinetics parameters of this process (Ea = 65.7 kJ•mol–1). Thermodynamic calculations indicated that JC adsorption on bronze surface obeyed Arrhenius adsorption isotherm and was characterized by an endothermic process (ΔH* = 54.7 kJ•mol–1).
文摘The main objective of the present study was to model the kinetics of essential oil extraction from swelled ground juniper berries by classic hydrodistillation(HD) and microwave-assisted hydrodistillation(MAHD). A new phenomenological kinetic model was developed on the basis of the juniper essential oil extraction mechanism that assumed three mass transfer processes occurring simultaneously: washing, unhindered diffusion and hindered diffusion. The new model was compared to the existing kinetic models. Among the tested models,the new model had the smallest mean relative percentage deviation and the highest corrected Akaike information criterion value. In addition, that, the new model was verified for HD and MAHD of essential oils from some other plant materials. On the basis of the above-mentioned facts, the new model can be recommended for modeling the kinetics of essential oil extraction by both HD and MAHD.
