daryoush afzali

In this study, iron oxide/cellulose acetate nanocomposite was prepared by electrospinning method and its performance was evaluated for removal of arsenic. Here, oleic acid coated magnetite nanoparticle was synthesized by co-precipitation method and was impregnated in cellulose acetate solution. This magnetite impregnated polymer solution, was electrospun to form nanocomposite polymer fiber. The cellulose acetate/iron oxide nanocomposite membrane was characterized by SEM and FTIR. The magnetic properties of composite nanofibers were characterized by using vibrational sample magnetometry analysis. The nanocomposite was used to remove arsenic ions from aqueous solution. Batch adsorption experiments were carried out to study the sorption behavior of arsenic ions as a function of pH, contact time and initial concentration. Experimental results showed that the maximum capacity of the cellulose acetate-iron oxide nanocomposite membrane for removal of arsenic from low concentration is 0.36 mg/g at pH 9. For better investigation of the adsorption mechanism, two isotherm models, Langmuir and Freundlich were tested. Based on the isothermal results, adsorption data were fitted well to Langmuir isotherm. The reusability of the nanocomposite membrane was confirmed for several adsorption and desorption processes by acid-alkali treatment.

With increasing water pollution, serious water shortages and increased pressure to save water, recycling and reuse of water has attracted more attention in various industries. Removal of silica from cooling water is essential for recycling and reuse of water. The aim of this study was to remove silica from water using magnesium oxide nanoparticles (MgO) synthesized by chemical deposition method.

Synthetic nanoparticles were successfully determined using field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). To determine the optimal adsorption conditions the batch system, the effect of important parameters such as pH (2-8), contact time (0-150 min), initial concentration of silica solution (50-1000 mg/L), adsorbent amount (0.01-0.14 g) and temperature (25-60 ˚C) were studied.

Under optimal conditions, an almost removal of 200 mg/L silica solution was achieved in 60 min reaction time. Equilibrium data were analyzed using the Langmuir and Freundlich isotherms. The adsorption process can be well described by the Langmuir model, and the maximum adsorption capacity was calculated as 75.76 mg/g. Synthetic data were analyzed using pseudo-first-order and pseudo-second-order equations. The pseudo-second-order model showed good agreement with the obtained data (R2 = 0.9949).

Due to the high potential of magnesium oxide nanoparticles in silica removal, it can be a good candidate for the removal of silica and industrial wastewater treatment.

In this work, Pd-Zn bimetallic nanoparticles were synthesized in different atomic ratios via a sonochemical method on pretreatment Vulcan XC-72R carbon. The synthesized structures were characterized by inductively coupled plasma-atomic emission spectroscopy, energy dispersive x-ray, powder X-ray diffractometry, and transmission electron microscopy. Electrocatalysis activity of synthesized nanostructures for ethylene glycol and glycerol as fuel was investigated and compared with monometallic palladium by cyclic voltammetry and linear sweep voltammetry analysis. Based on the obtained results, the highest and lowest activity in the oxidation process was obtained for Pd2Zn/C and Pd/C, respectively. The investigation of the voltammetric oxidation mechanism of these alcohols on the Pd2Zn/C coated anode indicates that the process is mass controlled and the species diffused into the electrode for oxidation. The results suggest that this bimetallic nanocatalyst is a good candidate as an anodic catalyst for the direct alcohol fuel cells.

In this study, Y-metal organic framework as a novel porous material was synthesized by affordable- ecofriendly and effective method of ultrasound assisted reverse micelle. Relevant analyses including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) surface area analysis were applied for physicho-chemical characterization of the products. Results obtained from experimental design showed that the experimental parameters affected on adsorption of CH4 gas pollution included temperature, time duration and pressure. These parameters and their interactions were designed by fractional factorial design method. The control of procedure was studied by analysis of variance and response surface methodology (RSM). RSM investigated the possibility of the Y-metal organic framework in optimal conditions to achieve maximum adsorption of CH4 pollution.

The existence of organosulfur compounds such as dibenzothiophene (DBT) in transportation fuels is not only a major source of acid rain, but also the reason many serious diseases of human respiratory system, such as lung cancer. Accordingly, efficient removal of DBT is very important. In the present work, magnetic nanoparticles were synthesis by co-precipitation method and then, these nanoparticles were covered with thin layer of polyaniline by chemical oxidation polymerization method in micellar medium using sodium dodecyl sulfate as surfactant. The synthetic product was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Langmuir and Freundlich isotherm models were used to fit equilibrium data for magnetic nanocomposite. Adsorption process could be well described by the Langmuir model (0.9899). The magnetic adsorbent afforded a maximum adsorption capacity of 118.42 mg g-1 at the optimized conditions (adsorbent dose, 0.01g; contact time, 15 min and pH, 9.3).

Nowadays due to water shortage, the use of treated wastewater as sustainable solution has been considered by industrial units; especially in industrial cooling units and boilers. However the use of treated wastewater also has its own problems such as corrosion of metal parts that they are often made of carbon steel. Therefore different methods such as coating have been considered by the industrial user of treated wastewater in order to reduce corrosion. So in this study, SiO2/TiO2 Ceramic Nano composite coatings was put on Carbon Steel plates by Sol-Gel method and by dipping process for 100 seconds and microstructure and properties of produced ceramic coatings were investigated. The results showed that ceramic Nano composite coatings improved corrosion properties of Carbon Steel. In order to improve the properties and performance of the coating, the molar ratio of components and factors affecting performance of coating were evaluated till optimum coating with Nano structure and highest level of corrosion protection is provided. To evaluate the performance of coatings for corrosion protection, polarization curves and to determine the surface morphology, scanning electron microscope was used. In order to study the bonds type and functional groups in the optimal sol, infrared spectrum was used. The optimum corrosion protection coatings were studied in 3.5% sodium chloride solution. The results showed that the ceramic optimal deposited coating provides effective protection for the surface of Carbon Steel against corrosion in 3.5% sodium chloride solution.

In the present study, removal of dibenzothiophene (DBT) from model oil (n-hexane) was investigated using magnetic activated carbon (MAC) nano-composite adsorbent. The synthesized nano-composite was characterized by FT-IR, FE-SEM, BET and VSM techniques. The MAC nano-composite exhibited a nearly superparamagnetic property with a saturation magnetization (Ms) of 29.2 emu g-1, which made it desirable for separation under an external magnetic field. The magnetic adsorbent afforded a maximum adsorption capacity of 38.0 mg DBT g-1 at the optimized conditions (adsorbent dose, 8 g l-1; contact time, 1 h; temperature, 25 °C). Langmuir, Freundlich and Temkin isotherm models were used to fit equilibrium data for MAC nano-composite. Adsorption process could be well described by the Langmuir model. Kinetic studies were carried out and showed the sorption kinetics of DBT was best described by a pseudo-second-order kinetic model. In addition, the MAC nano-composite exhibited good capability of recycling to adsorb DBT in gasoline deep desulfurization.

Thallium is widely found in nature, but the only inorganic stones full of this element are crookesite and lorandit. It is also found in pyrites of copper, lead and inorganic stones. The element and its compositions are toxic and harmful to the environment; therefore, its application requires caution and further research. It is important to develop sensitive and accurate analytical methods to determine trace levels of thallium in environmental and real samples. In this research, dispersive liquid-liquid microextraction based on solidification of floating organic drop as a sample preparation method was used for separation and preconcentration of ultra-trace amounts of thallium in soil samples prior to graphite-furnace atomic-absorption spectrometry. Investigated effective parameters on extraction include pH, the amount of chelating agent, type and volume of extraction solvent and extraction time. Under optimum conditions, the calibration curve was linear in the range of 0.2-10.0 ng mL−1 of thallium in the original solution, with limit of detection of 0.03 ng mL−1. The relative standard deviation (RSD) for ten replicated determinations of thallium ion at 5.0 ng mL−1 concentration level was calculated as 3.3%. The proposed method was successfully applied to the determination of thallium in soil samples.