Akl M. Awwad

Green synthesis of silver nanoparticles using carob leaf extract and its antibacterial activity

BackgroundThis paper describes a rapid and eco-friendly method for green synthesis of silver nanoparticles from aqueous solution of silver nitrate using carob leaf extract (Ceratonia siliqua) in a single-pot process.ResultsFormation of stable silver nanoparticles at different concentrations of AgNO3 gave mostly spherical particles with a diameter ranging from 5 to 40 nm. It was observed that the use of carob leaf extract makes a fast and convenient method for the synthesis of silver nanoparticles and can reduce silver ions into silver nanoparticles within 2 min of reaction time without using any severe conditions. Green synthesis of silver nanoparticles (AgNPs) was characterized by UV-visible (UV–vis) spectroscopy, scanning electron microscopy, atomic absorption spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction (XRD). The UV–vis spectra gave surface plasmon resonance for synthesized silver nanoparticles at 420 nm. The XRD analysis showed that the AgNPs are crystalline in nature and have face-centered cubic geometry.ConclusionFurther, the AgNPs showed an effective antibacterial activity toward Escherichia coli pathogen.

Equilibrium and kinetic studies of cadmium(II) and lead(II) ions biosorption onto Ficus carcia leaves

BackgroundFicus carcia leaves (fig leaves) for the removal of cadmium(II) and lead(II) ions from aqueous solutions have been investigated.ResultsThe biosorption of cadmium(II) and lead(II) ions was found to be dependent on the solution pH, initial metal ion concentrations, biosorbent dose, contact time, and temperature. The experimental equilibrium biosorption data were analyzed by two widely used two parameters, Langmuir and Freundlich isotherm models.ConclusionsLangmuir isotherm model provided a better fit with the experimental data than Freundlich model by high correlation coefficients R2. Kinetic studies showed that pseudo-second-order described the biosorption experimental data better than the pseudo-first-order kinetic model.

Biosorption of cadmium (II) onto loquat leaves (Eriobotrya japonica) and their ash from aqueous solution, equilibrium, kinetics, and thermodynamic studies

Biosorption of Cd(II) onto loquat leaves (LL) powder and loquat leaves ash (LA) from aqueous solution has been investigated. The extent of biosorption of Cd(II) ions was found to be dependent on the solution pH, biosorbent dose, initial cadmium ions concentration, contact time, and temperature. The experimental equilibrium biosorption data were analyzed by three widely used two-parameter Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm equations. The Langmuir isotherm model provided a better fit with the experimental data than Freundlich and Dubinin-Radushkevich (D-R) isotherm models by high correlation coefficients R2. The biosorption capacity of LL and LA was found to be 29.240 mg g−1 and 21.322 mg g−1 for Cd(II) ions, respectively. The mean adsorption energies evaluated using the D–R model indicated that the adsorption of Cd(II) onto loquat leaves and their ash mainly proceeds through binding surface functional groups, i.e., were taken place by physisorption. The thermodynamic analysis indicated that the biosorption behavior of cadmium ions onto LL and LA biosorbents was an endothermic process. The negative sign values of ΔGo and positive values of ΔHo revealed that the biosorption process was spontaneous and endothermic. Adsorption mechanisms were also investigated using the pseudo-first-order and pseudo-second-order kinetics models. The kinetic results showed that the adsorption of Cd(II) onto LL and LA followed well pseudo-second order kinetics.

Toxicity of nanoparticles against Drosophila melanogaster (Diptera: Drosophilidae)

In recent years, nanotechnology has become one of the most promising new approaches for pest control. In our screening program, laboratory trials were conducted to determine the effectiveness of five sources of silver nanoparticles (Ag NPs) and sulfur nanoparticles (S NPs) on larval, pupal, and adults of the fruit fly Drosophila melanogaster. Nanoparticles of silver and sulfur were synthesized through reducing, stabilizing, and capping plant leaf extracts method and different concentrations (10, 50, 100, 200 ppm) were tested on D. melanogaster. Results showed that silver nanoparticles (Ag NPs) were highly effective on larvae, pupae, and adults mortality and egg deterrence. On the contrary, none of the tested nanoparticles has a significant effect on pupae longevity. The results also showed that silver nanoparticles can be used as a valuable tool in pest management programs of D. melanogaster.

Estimation of excess molar volumes and theoretical viscosities of binary mixtures of benzene + n-alkanes at 298.15 K

Excess molar volumes, (

Biosorption of Ni(II) from electroplating wastewater by modified (Eriobotrya japonica) loquat bark

V_{text{m}}^{text{E}}

Densities and volumetric properties of (N-(2-hydroxyethyl)morpholine + ethanol, + 1-propanol, + 2-propanol, + 1-butanol, and + 2-butanol) at (293.15, 298.15, 303.15, 313.15, and 323.15) K

VmE), have been derived from the literature viscosity data for the binary mixtures of benzene with n-hexane, n-octane, n-decane, n-dodecane, n-tetradecane, and n-hexadecane as a function of composition at 298.15xa0K and atmospheric pressure conditions. The