Islamic Azad University North Tehran Branch

About: Islamic Azad University North Tehran Branch is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Adsorption & Catalysis. The organization has 868 authors who have published 968 publications receiving 9987 citations.

Characterization and nonlinear optical properties of PVP/TiO2 nano-fibers doping with Ag colloid nano-particles

Abstract: We synthesized PVP/TiO 2 nano-fibers doping with Ag colloid nano-particles by electro-spinning method. These nano-fibers were characterized by UV/visible/NIR spectroscopy, SEM and XRD. The image of SEM showed that the synthesized nano-fibers were monotonous and without knot and had a diameter about 150 nm. We also measured the nonlinear refractive and absorption indexes of the sample in three different intensities using the single beam Z-scan method by a continuous wave (CW) He–Ne laser at 632.8 nm wavelength. The nonlinear refraction indexes of these nano-fibers were measured in order of 10 −7 (cm 2 /W) with negative sign and the nonlinear absorption coefficient was obtained in order of 10 −3 (cm/W).

Synthesis and characterization of activated carbon@zerovalent iron–nickel nanoadsorbent for highly efficient removal of Reactive Orange 16 from aqueous sample: experimental design, kinetic, isotherm and thermodynamic studies

Abstract: A simple and fast method based on activated carbon@nanozerovalent iron–nickel (AC@nZVI/Ni) nanoadsorbent was developed for highly efficient removal of Reactive Orange 16 (RO16) from aqueous samples. AC@nZVI/Ni nanoadsorbent was characterized by FT-IR, XRD, SEM and EDX. Effects of diverse factors including the solution value, adsorption time, AC@nZVI/Ni dosage and initial RO16 concentration were explored via experimental design methodology, and the highest removal percentage of 100% was obtained under the optimal conditions. Langmuir and Freundlich models were employed to interpret the equilibrium adsorption data by utilizing different initial concentrations of RO16. The data are fitted to the Langmuir model, with a maximum adsorption capacity of 10.53 mg g−1 and a Langmuir constant of 13.51 L mg−1. The kinetic data were fitted to the pseudo-second-order model. Finally, thermodynamic study was accomplished at diverse temperatures and the data revealed an exothermic nature.

Application of a new modified magnetic nanoparticle as a selective sorbent for preconcentration and extraction of europium in environmental water samples prior to ICP-OES determination

Abstract: The presented study investigates the application of new magnetic core–shell silica nanoparticles as a selective sorbent for magnetic solid phase extraction and determination of europium (Eu) in environmental water samples. Separation was performed by using a small amount of sorbent with high extraction capacity according to the special properties of magnetic nanoparticles. The elution step was performed by 1.5 mL nitric acid (1 mol L−1) and the desorbed analyte was introduced to ICP-OES. The effect of different parameters such as pH, extraction and desorption time, type and concentration of eluent,… were investigated and optimized. Under the optimized conditions the detection limit for determination of Eu was 0.04 µg L−1 and the relative standard deviation (RSD, C = 200 µg L−1, n = 6) was 3.2 %. The linearity of the method was obtained within the range of 0.5–1,000 µg L−1 and the extraction efficiency was 93.5 %. The accuracy of the method was evaluated by calculating the relative recovery by analyzing real water samples and good recoveries (95–106.5 %) were achieved, showing the reliability of the method for determination of europium in real samples.

Biodegradation of phenol from a synthetic aqueous system using acclimatized activated sludge

Abstract: Phenol is one of the aromatic hydrocarbons. Phenol and its derivatives are highly toxic. These pollutants can be observed in the effluents of many industries. This research investigates the removal of phenol by the use of activated sludge in a batch system. The effects of influencing factors on biodegradation efficiency have been evaluated. The main factors considered in this study were the volume of acclimatized activated sludge inoculation, pH, temperature, and initial concentration of phenol. The inoculation volumes of 1, 3, and 5 mL of acclimatized activated sludge were taken into account. Different pH values of 3, 5, 7, 9, and 11 were examined. The experiments were conducted for temperatures of 25, 30, 35, and 40 °C and initial phenol concentrations of 400, 800, 1,000, and 1,500 ppm. The results show that the acclimatized activated sludge has a high capacity for the removal of phenol. From a 100-mL aqueous solution was removed 1,500 ppm of phenol after 80 h. Furthermore, maximum phenol removal was observed for an inoculation volume of 5 mL for three different phenol concentrations of 100, 400, and 800 ppm. The best pH was 7 for the biodegradation process, and the optimum temperature was 30 °C. It was further found that an increase in the phenol concentration increased its removal time. Moreover, the activated sludge could effectively remove about 99.9 % of phenol from a synthetic aqueous solution in a batch system.

Investigation of cutting quality and surface roughness in abrasive water jet machining of bone.

Abstract: The abrasive water jet machining is known as a cold cutting process and can be effective for developing cut in the bone in orthopedic surgery to prevent thermal necrosis. This research examined sur...