فهرست مطالب آرزو قادی

The use of antibiotics as major drugs in infectious diseases has always been associated with two problems of side effects and drug resistance. The compounds found in various plants have been used as a treatment method since the past until today because medicinal plants possess side effects compared to other drugs. Given that different species of Echinops dichorus L. plant have indicated good antimicrobial effects, in this study antimicrobial effects of ethanol and aqueous extracts of Echinops dichorus L. plant have been investigated by disk diffusion method and determining the minimum inhibitory concentration (MIC) on the 24-hr culture of Escherichia coli (E. coli) standard strain. Echinops dichorus L. plant was dried after collection and its ethanol and aqueous extracts of were prepared by maceration method. Afterward, the concentrated and dried samples were stored in clean containers under standard conditions for further tests. The antibacterial effect of different concentrations of the extracts was determined by agar diffusion and compared with penicillin, gentamicin, and tetracycline antibiotics. Ethanol and aqueous extracts possessed a MIC of 31.25 µg/ml (diameter of the bacterial growth inhibition (halo): 12 mm) and 125 µg/ml (diameter of the bacterial growth inhibition (halo): 10 mm), respectively, as anti-microbial effect against E. coli.

In this research the separation of methane and carbon dioxide gases by using the Nano composite membrane including poly ether block amide and poly vinyl alcohol as polymers with multi wall carbon Nano tubes is investigated.  The results of many studies show that the combinations of polyether block amide have great efficiency in making the polymeric membranes for separating gas. However, efforts are doing to improve the permeability and selectivity of such membranes.  In this study made membrane was made by using the solution molding and combining the percentage of 80 to 20 for polyether block amide/poly vinyl alcohol and carbon Nano tube with the amount of 0.5,1 and 2 percent of weight is used. Morphology and structure of the membrane made by TGA, FE-SEM, XRD and FTIR were checked.  Measuring the amount of permeability of the built membranes was done by using constant pressure-variable volume method.Total results showed that with the increase of pressure up to 8 bars, the amount of permeability of carbon dioxide and methane gases increases and the maximum amount of permeability for carbon dioxide and methane gases respectively are 4w6 and 36.44 bar.  The amount of selectivity for binary gases of carbon dioxide- methane increases with the increase of the amount of nanoparticle and the maximum amount in membrane contains 2percent of carbon nanotube and 8bar pressure with the amount of 11.69.

The wastewater obtained from sugar production cannot be naturally degraded due to the presence of various color precursors, colored impurities, lime carbonation sludge and other organic impurities. In this study, optimization of the effective parameters for the sugar industry wastewater treatment is investigated using photo- Fenton process and response surface methodology.

 This empirical research was conducted on a laboratory scale on refined wastewater obtained from sugar beet factory (Qazvin, Iran), in ternms of the intensity of contamination, considering the reduction of the three factors including COD, phenolic, and color content using the advanced oxidation process (photo- Fenton process). In order to optimize the ocndions for wastewater treatment, the results of these experiments wre ultimately optimized by response surface methodology.

The results obtained that the optimal condition for color and phenolic removal were: pH of 6.1' reaction time 15 minutes' Fenton's reagent (Fe2+/H2O2) concentrations: 20/1500 of ppm. Under these conditions, the color and phenolic reduction were achieved 73.92% and 93.9%, respectively.

The photo- Fenton process has a good efficacy in treating the sugar industry wastewater in the removal of important pollution parameters such as color impurities, phenolic compounds, and COD.Also, the statistical results showed that the pH parameter, Fenton's reagent concentration and contact time were significant during treatment process (p<0.05).

In the dairy industry, natural gums can be used to stabilize emulsions such as cocoa milk. Among the types of gums are carboxymethylcellulose and capacaraginan, which are used ias bulking, thickener, Stabilizer, primer, and emulsifying in the food industry. Due to the challenges in cocoa milk storage methods, in the present study, we investigated the effect of capacaraginan, carboxymethylcellulose gums, and their combination on the physicochemical properties of cocoa milk with two reduced protein levels (2.4% and 2.6%) has been paid. For this purpose, by measuring pH, soluble solids, apparent viscosity, sedimentation rate, and color parameters during storage for 5 months at 4 ° C, the effect of these gums on the stability of cocoa milk emulsion was investigated. Also, after sensory testing of cocoa milk including color, texture, and flavor during the storage period at 5-day intervals, it was observed that with increasing concentration of hydrocolloids, soluble solids, viscosity, and saturation index increased, while pH, sediment, and yellow and redness index will decrease. Samples containing 0.1% of synthetic gum showed the highest sensory evaluation score. Based on the results obtained from physicochemical and sensory evaluations, using 0.1% of the combined gum of capacaraginan: carboxymethylcellulose for the preparation of cocoa milk with protein content in the range of 2.4 to 2.6% stable properties can be achieved in cocoa milk.

Sulfur is one of the elements in fossil fuels that is converted to sulfur dioxide, which is one of the most important air pollutants, when burned in a car engine. In the present study, the adsorption capacity of an organic sulfurized compound from a diesel fuel model containing 300 ppm thiophene was evaluated using x13 zeolite modified with 3% by weight of copper metal. Moreover, the effect of three parameters of contact time (15, 30, 60, and 120 min), adsorbent value (0.5, 1, 2.5 and 3.5 g) and temperature (25, 40, 50 and 60 °C) was assessed in a discontinuous system. In order to activate the adsorbent surface cations, x13 zeolite was washed with deionized water and 0.1 M copper nitrate salt and then copper nanoparticles were loaded on it. The maximum adsorption capacity was 2.5 g of adsorbent at 60 min at room temperature, and the amount of thiophene for adsorption modified with copper nanoparticles increased from 300 to 138 ppm. The adsorption results showed that an increase of more than 2.5 g of adsorbent would not cause a significant change in the adsorption efficiency. In addition, FT-IR, SEM and N2 physisorption studies showed that the adsorbent would maintain its regular structure after nanoparticle loading. Finally, the modified zeolite showed better performance for desulfurization of the diesel fuel model.

Today, due to the growing population and increasing agricultural and food production, the use of toxins and organophosphate and organochlorine pesticides, especially Edifenphos, is increasing in the agricultural sector. One of the most effective ways to remove such toxins is to use the adsorption method. Therefore, the present study investigated the removal of Edifenphos fungicide from aqueous solution using polypyrrole composite on natural perlite zeolite. It is notworthy that each experiment was performed in a discontinuous system. For this purpose, after removing possible impurities in perlite through heating at 550 °C and then activating perlite with 0.06 N sulfuric acid, PPy/perlite nanocomposite was prepared. The structure of the adsorbents synthesized was identified using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. Then, the effect of experimental parameters of pH, contact time, adsorbent mass, and temperature on adsorption was studied. The results showed that the optimal conditions for adsorption of Edifenphos by PPy/Perlite were pH 6, contact time 18 min, and adsorbent amount of 0.3 g/100 ml. Examination of the effect of temperature also showed that increasing the temperature has a positive effect on the removal efficiency. Finally, the study of the process thermodynamics showed a spontaneous and endothermic process.

Zinc hydroxide chloride nanostructure was successfully synthesized through a simple method at low temperature by sonochemical process. The morphology and crystalline of the products were analyzed by XRD, FESEM and TEM. The effect of independent variables including contact time, solution pH, adsorbent dosage and the concentration of dyes on response performance with response to surface methodology based on Central Composite Designs. ANOVA was applied to analyze the responses.  Investigating the isotherm and  kinetic models showed that the experimental data were correlated with Temkin adsorption isotherm model and pseudo-second order kinetic. In optimal conditions, Zinc hydroxide chloride nanostructure has the potential to remove Reactive Blue 39 dye.

In this study, the process of separating lycopene carotenoid pigment from tomato powder by industrial hemicellulose enzyme was studied. For this purpose, the effects of temperature change, enzyme concentration, incubation time, pH were all studied at optimum points. The research is based on the effectiveness of the enzyme in different conditions on the amount of pigments extracted from tomato powder and obtaining the optimal extraction points by statistical analysis of the results. To extract the pigment in this study, solvents of hexane, ethanol, acetone in a ratio of 1: 2:1 and incubation at 30 ° C for 16 hours were used for the full effectiveness of the solvent. For each variable, three levels were defined. In order to target the experiments, Taguchi design was used for the experiment design table and included nine experimental rows. For each experimental row, three replications and a control containing an enzyme-free sample were considered. Pigment-containing solutions were transferred to spectrophotometry at the end of the separation stage and after recording the data and statistical analysis, it was observed that the effectiveness of the enzyme concentration variable was much higher than other variables, so that the highest average pigment extraction concentration at 500 μg = .0.450 Separately, each variable has optimal points for the incubation temperature of 40 degrees and for the incubation time of 60 minutes, for pH = 4, the enzyme concentration is 200 micrograms per liter for every 5 grams of tomato powder.

Methylene blue dye is the most common dye for dyeing cotton, wool and silk. Inhalation of this dye can cause respiratory distress and while direct exposure to it can also cause permanent eye damage, burning sensation in the exposed areas, Nausea and vomiting, excessive sweating and mental disorders. In this paper, silver nanoparticles was synthesized via a simple method. Various techniques such as FESEM, XRD, UV-Vis DRS were used to identify the morphology, structural composition and optical properties of synthesized silver nanoparticles. The results of UV-Vis DRS showed that the prepared silver nanoparticles effectively improved the efficiency of the visible light response in the process of photocatalytic degradation of methylene blue dye. The results of pseudo-first-order linear kinetics showed that the value of k increased with increasing of MB dye concentration from 0.0264 to 0.0614 min-1. In general, nano-silver synthesis showed a high potential in removing MB dye from aqueous solutions.

Chlorination for disinfection of drinking water leads to the formation of by-products like trihalomethanes, due to the reaction of chlorine with natural organic compounds like tannic acid, fulvic acid, and humic acid. Due to the carcinogenicity of these compounds, rapid measurement of these compounds in water requires rapid and sensitive analytical methods. In this study, solid-phase microextraction was used as a solvent-free separation and pre-condensation technique to determine four common halomethanes in drinking water using gas chromatography with mass spectroscopy. In this technique, polydimethylsiloxane fiber was used as headspace method for pre-condensation and extraction of the analyte from the aqueous sample. Detection and measurement of the extracted analytes was conducted using thermal desorption in the injection chamber of gas chromatography-mass spectroscopy. Various parameters affecting the efficiency of trihalomethane extraction, including the extraction and desorption temperature, the extraction and desorption time in addition to the amount of salt were investigated and optimized. Under optimal conditions, the concentration factor of detection limit was obtained in the range of 2.1 to 4.4 µg/l and the linear range of 20 to 600 µg/l. Relative standard deviation was obtained to be between 2.5% and 3.1% at the concentration of 30 µg/l trihalomethanes in water. The method was successfully applied to extract and determine trihalomethanes in drinking water in cities of Mazandaran Province.

Chemical engineering is one of the most versatile and largest engineering fields. Chemical engineering graduates have different status based on their area of study and responsibility in society. Since a low level coordinator is recognized as a manager, chemical engineers could benefit from management science for all control processes, leadership, organizing projects, decision making, creativity and innovation, etc. Therefore this paper emphasizes projects necessity of management course for chemical engineering as an obligatory course, which is a basic need for update management.