نشریه شیمی و مهندسی شیمی ایران
سال سی و چهارم شماره 2 (پیاپی 76، تابستان 1394)

Composite coatings of polymer/ceramic are one of good options for corrosion inhibition in water and water sewage pipelines. In this work, ZnO nanopowder was synthesized by combustion sol gel Process. Then, two coating types of epoxy/ZnO and polyaniline/ZnO were applied on steel pipes. The nano powder and the coatings were characterized by X-Ray Diffractometry (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform-Infrared Spectroscopy (FT-IR.(Concentration of coating's elements diffused into water was investigated. Results show that concentration of metals diffused into the water are less than standard limited concentrations and might not be health hazardous. To investigate the corrosion behavior of the applied coating, open circuit potential was applied on both coatings. To evaluate the capability of the coatings in corrosion speed decrement, Toefl curves are assessed. Results show that ZnO nano particles (25nm) in the polymer matrix can enhance corrosion resistance of steel pipes enormously and in this case epoxy/ZnO coatings are superior.

This research is on the thermal decomposition of ammonium perchlorate activated by addition of commercial CuO nanoparticles. CuO nanoparticles were characterized by X-Ray Diffraction (XRD) and Transition Electron Microscope (TEM). TEM image shows that the CuO nanoparticles have a nearly spherical morphology. The catalytic activities of the CuO nanoparticles on the thermal decomposition of Ammonium Perchlorate (AP) were evaluated by Thermo-Gravimetric Analysis and Differential Scanning Calorimeter (TGA/DSC), which results show that, in presence of 2 and 5 wt% of CuO nanoparticles, the thermal decomposition temperature of AP decreased by 61.11 and 72.59 °C, respectively. Also, results imply that the heat decomposition of AP was increased by 528.51 and 535.11 J/g in the presence of 2 and 5 wt% of CuO nanoparticles, respectively. TGA data was used to evaluate kinetic parameters of samples by model fitting method and values of A, Ea, ∆G≠, ∆H≠, and ∆S≠ were obtained.

Polymers can be used as supporters in the synthesis of organic compounds. The most important reason in using polymers is the ease of separation. Polymers supporting the catalyst are the most interesting kind of polymers in supporting reactions. These polymers are recycled in a proper form for the re-use with a simple filter or the temperature. Some polymers which are used frequently include Polyethylene glycol and Polyvinyl alcohol. The polymers hybridized are the most appropriate choice for providing heterogeneous catalysts, recycle, and the use of them in reactions. The functions of catalysts, mostly, are in providing catalysts and also in applying them as supporters of Pt, Pd, Au, Ni, Fe and Ag metals. Providing effective heterogeneous catalysts, which are recyclable by using metal supporter polymers, is utilized for some reactions like cross coupling reactions. These reactions have the wide range of applications in pharmacy, agricultural chemistry and industry. In this study, we have extracted the Ligand for Palladium from PVA. It is done by conducting chemical reaction and the reformation of which in this process. Due to the appropriateness of supportive polymer, it has been provided with hybrid in order to promote the separation problem after the chemical reactions. Therefore, the general design is as the following: A. Preparation of Silica-PVA hybrid, B. Oxidation of Silica-PVA hybrid by Jones reagent,C. Preparation of imine by reaction of Hydroxylammonium chloride with oxidized Silica- PVA hybrid, D. Synthesis of Silica-PVA hybrid and Palladium complex, E. Heck reaction of idobenzene and methylacrylat in the presence of Silica-PVA Pd complex as catalyst. The reaction products were identified by IR, UV-Vis, and GC-Mass analysis.

In this study, polyacrylamide-ZnO composites were synthesized and the behavior of the obtained composites were studied as electrode materials in electrochemical supercapacitors. The morphology, crystal structure, and thermal stability of the composites were examined by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), and FT-IR. Electrochemical properties were determined by Cyclic Voltammetry (CV). Cyclic voltammetry curves confirmed the reversible electrochemical behavior of the composites. The composite oxide content was found to be 15% of the composite’s capacity, with 30% and 50% for zinc oxide. The results indicated that although presence of zinc oxide in the composite has effective role on the electrochemical behavior of the composite, the morphology and thermal stability of the composite determined the composite’s capacity as an electrode in electrochemical supercapacitors.

In this research, treatment of wastewater containing azo dye of acid orange 7 was investigated. According to low capability of conventional photocatalytic process in treating colored wastewater in comparison to ozonation, and high ability of ozone in discoloration, system of ozonation/ photocatalytic processes was used for treatment. Nano TiO2 was used as photocatalyst. The effect of pH (3, 5, 7, 9) and initial concentration (5, 35, 50 mg/L) on removal efficiency of organic pollutant was investigated by ozonation/photocatalytic system and phtocatalytic process. An experimental design based on the response surface method was applied to assess the optimum level of operating parameters on the treatment energy consumption in textile industry wastewater. Based on experimental design data, optimum conditions were achieved at 2.95 day of retention time, pH of 5, ozone injection rate of 1.2 g/h, 128 mg/L of nano TiO2 and 120 Wt UV-A light source.

After the onset of the industrial revolution, the concentrations of greenhouse gases in the atmosphere increased rapidly. Global warming is caused by the emission of greenhouse gases. Carbon dioxide emissions are the most important cause of global warming. Now, there are several methods to remove carbon dioxide from gas streams. One of the proposed methods is the use of zeolites as the adsorbent which can separate CO2 using molecular sieve method. In this study, CO2 removal from Sabzevar Cement plant flue gas by Sabzevar zeolite was investigated.For this purpose, a laboratory - scale column was made and the effect of three factors including the size of zeolite, height-to-diameter ratio of the column (L/D), and gas inlet pressure were investigated in three levels using Taguchi method. ANOVA results showed that in the range of variables, the size of zeolite is the most important factor on the adsorption process. Also, L/D factor had a significant effect on the adsorption process. Under the obtained optimum conditions that involved the size of zeolite 2-2.36 mm, L/D 10.8,gas inlet pressure 90-98 kPa, about 80% of CO2 was removed from the flue-gas after 10 minutes and more than 60% of it was also removed after one hour by the zeolite column.

The oily water from oil refineries and oil distribution centers are one of the most important environmental pollutants in recent decades that make serious damages on the environment. Membrane technology can play an important role in treatment of these kinds of wastewaters as there is no need for chemical addition for breaking the emulsion and the treatment facilities are highly automated. In this research, the performance of different membranes in oily water treatment was reviewed and the performance of nanostructure polyethersulfone (PES) hollow fiber membranes in oil/water separation process was investigated and the effect of operating parameters such as pressure, oil concentration and cross flow velocity of feed on the membrane performance is studied. Increasing the pressure makes higher membrane fouling that reduces the flux of treated water so P = 1 bar, high liquid velocity and low feed concentration were selected as the optimum operating conditions. Membrane surface fouling by oil coarse particles is one of the main problems in membrane processes. Oil particles precipitate on the membrane surface and form second layer on the membrane surface. Second layer formation is leading to flux reduction and enhanced rejection. The effects of membrane fouling at high pressures (2 bar and 3 bar) is quite obvious, so at high pressures the difference in flux with fresh membrane is more evident. All the fabricated PES membranes showed complete separation of oil from water. Therefore, they can effectively be used in oily water treatment.

One of the most efficient systems for transferring the thermal energy from the power plants to the environment is the wet cooling towers. Dissolved impurities, which are entered into the cooling tower by makeup water, can be limited by the blowdown system. In the present paper, the water quality in the wet cooling towers was studied. Analyses showed that the continuous blowdown is more efficient than periodic one. Furthermore, a group of the wet cooling towers with a certain amount of blowdown, the blowdown system of towers can be utilized to reduce the dissolved impurities. For a special case, the effectiveness of the blowdown in a group of five cooling towers has been investigated, and it was shown that with 20 percent blowdown, the average impurity levels in towers can be reduced from six times of the dissolved impurities in water-supply to 2.74.

Solidification/Stabilization (S/S) is used for treatment of various types of hazardous wastes. A systematic study was conducted for treatment of electroplating sludge by Solidification/Stabilization (S/S) with Ordinary Portland Cement (OPC), with the addition of distilled water, lime and magnesium oxide (MgO). Response Surface Methodology (RSM) and Artificial Neural Network (ANN) in combination with Central Composite Design (CCD) were employed to develop the predictive models for simulation and optimization of S/S process. The independent variables were the amount of MgO, electroplating dried sludge, lime, distilled water, while the compressive strength, concentration of zinc and chromium in Toxicity Characteristic Leaching Procedure (TCLP) leachate of the solidified waste after 28 days of hydration were the response variables of 30 specimens. Both RSM and ANN models have been developed based on the experimental designs. The generalization and predictive capabilities of both RSM and ANN were compared by unseen data. Therefore, ten experiments were designed randomly and the predicted responses obtained by ANN and RSM were compared with the experimental results. The results show that the optimized method by ANN or RSM can be used as a confident method for determination of compressive strength of the solidified wastes and concentration of zinc and chromium in TCLP leachates. However, the data calculated by ANN model are more similar to experiments results than that of RSM predicted results. according to RSM and ANN, optimum combination were found 15.3 g, 100 g, 3.6 g, 19 g and 49.5 mL and 14.9 g, 100 g, 3.4 g, 18.5 g, 46 mL of MgO, waste, lime, cement and distilled water, respectively.

Human Epidermal Growth Factor (hEGF) with 53 amino acids and a molecular weight of 6.2 KD is a protein that stimulates the growth of various cell types. The purpose of this study was to apply a novel method for purification of the recombinant hEGF that was expressed in recombinant Escherichia coli BL21(DE3). The recombinant strain produced hEGF in form of intracellular so it was necessary to disrupt cell wall of recombinant E. coli and then purify hEGF from inclusion body. Renaturation and purification protocol, which was used in this study, was a simple and efficient one that had three stages including unfolding, purification by means of ultrafiltration and centrifugation and finally refolding of unfolded rhEGF molecules. SDS-PAGE and Reverse Phase High Performance Liquid Chromatography (RP-HPLC) were used as analytical methods to investigate the results. The purified protein was analyzed by SDS-PAGE and RP-HPLC and the results were shown more than 99% purity.