نشریه کاربرد شیمی در محیط زیست
پیاپی 31 (تابستان 1396)

Investigation of absorption and removal of several kinds of azo and un azo dyes that used in food and dye industrials and after composition, enter the environmental wastewaters, with chitosan as an absorbent. Anionic dyes like sunset yellow and carmoisine that used in this research belong to the sulphunated food azo dyes and dissolved in water. This matter use for coloring of different products like sugar cane, Nutritional supplement, soft drinks, jelly, different fruit juices and etc.
We can see from results that the maximum removal percentage of sunset yellow and carmoisine, with the chitosan in the pH=5 and in the upper and lower pH values, the yield is decreased. It sees from results that the maximum removal for carmoisine in the 50 min and for sunset yellow is in the 40 min for chitosan absorbent.

In this research, produced and mixed physical and mechanical properties of polyethylene  terephthalate / polyethylene naphthalate was done. Alloy PET / PEN with different weight percentages relative to the 100/0, 25/75, 50/50, 75/25, 0/100 percent by weight using a ZSK twin-screw extruder at a temperature of 280 and 300 °C and at the time of incorporation of 10 and 30 minutes is provided. similar to PET, PEN ability to create links and generate copolymer PET / PEN is capable, but the use of PET because of the high price of PEN/ PEN to strengthen the combined percentages higher than 25% gets involved not affordable. That is why the composition of the 25/75 because of the physical and mechanical properties appropriate and cost-effective, optimized alloy composition of PET / PEN in the study suggested.

Industrial equipment has its own complexities that the greater the complexity, the probability of major events in operations will be further processed. Including industrial complex, the oil industry that oil depots risk management process operations Iranian Oil Products Distribution Company is the point of this study. Iranian Oil Products Distribution Company, which has 37 oil storage area martyr Behfar Ardabil region was chosen as a case study. In fact, this study may provide a local model provides risk management operations of the country's oil depots. Therefore, risk method for calculating risk-based maintenance is used. To collect data, the Delphi method is used. Risk number using localized factors can be calculated. But this classic evaluation of risk is always associated with uncertainties.Uncertainty can result from lack of accurate data and adequate, express different types of risks, defects and errors in data measurement and so on. The best and most widely used approach to overcome this uncertainty, fuzzy methods are introduced. In this study, fuzzy approach to risk modeling process operations is employed. The risk value is calculated using fuzzy model.

Different methods have been proposed for the purification of contaminated areas, which include physical methods such as burning, ventilation and temperature absorption. Chemical methods include sedimentation, solvent extraction, oxidation and reduction. In contrast, biodegradation of contaminated soils, the use of green plants and microorganisms in soil remediation and the removal of environmental pollutants, is a low cost method without harm to soil biology and ecosystem. This approach has been increasing day by day for cheap reasons, simplicity, lack of adverse effects on physical, chemical and biological properties of soil, increasing vegetation cover and its positive consequences. Fungi can degrade oil pollution by analyzing petroleum products. They can change or eliminate harmful substances and, consequently, remove them from the reach of other organisms and reduce environmental hazards. During biodegradation of contaminated areas with oil, harmful compounds can be metabolized by enzymes into the fungus or soil. The plant increases the oxygen content of the soil, and oxygen is a determinant factor in the growth and activity of aerobic microorganisms in the soil, as well as the determinant factor in the first stage of the decomposition of a large number of chemical compounds, including aromatic compounds.

This paper deals with the optimal condition for synthesis of three-component Magnetic nanoparticles (MNPs) of iron, copper and manganese using co-precipitation method. The response surface methodology (RSM) with Central composite design (CCD) was used to investigate the optimal condition to syntheses the magnetic nanoparticles. The structures of MNPs were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. The influences of reaction temperature (60-85 °C) and stirring rate (500-1500 rpm) during the precipitation were considered. The appropriate conditions for the synthesis of these particles found to be 60 °C and 1500 rpm. In this condition a nanoparticle of 43 nm dimensions was obtained. The nanoparticles prepared in optimal conditions, can be used for removal of 16 violet basic dye from aqueous solutions.

In green chemistry we are always looking for materials that preparation or use of them does not pollute the environment. It is clear that lemon juice as a natural compound can be used as a green solvent-catalyst in a wide range of chemical reactions. In this study, lemon juice was used for condensation of aniline and benzaldehyde derivatives to prepare N-benzylidene aniline substituted.  The synthesized compounds were characterized by FTIR, 1HNMR and 13CNMR spectroscopies. In the process of synthesis of these compounds no unnatural solvent were used, that emphasizes on the greenness of these reactions. Finally, antibacterial activities of synthesized compounds were studied against Gram-positive and Gram-negative bacteria strains. Results showed that the 3e compound has the highest antibacterial activity when compared to the other synthesized compounds.

Optimizing energy consumption is important for reducing environmental degradation and reducing operating costs. In this project, Pinch technology is used at the Butanol Recovery Unit to save energy. The Utilities include cooling water (20 ̊C) and pressure steam for exchanging heat with a mixture of water and butanol with different mixing rates. By reducing the optimal minimum temperature difference between hot and cold currents of 5°C (ΔTmin = 5 ̊C), the thermal load of the hot and cold Utilities can be reduced. This work by targeting of around 16% and 6%, will be decrease for hot and cold Utilities, respectively. In this project with targeted goals, operating costs per year can be reduced up to 13.3 percent in ideal condition. With increasing and lowering of new area the capital costs will increase to 31,662 $ an additional surplus on initial spending. Energy saving costs are reduced by up to 10.1%, with a return on investment of 5.9 year.

In this paper the thermal analysis performance of heat exchanger is improved by twisted tapes and nanofluid simultaneously. Results of the system are assessed by a rapid design algorithm (RDA) and compared to conventional shell and tube heat exchanger and other traditional including the heat exchanger with nanofluid and twisted tape. Based on the RDA, a relationship between heat transfer coefficients, pressure drops and heat transfer area is derived. Using the maximum allowable pressure drops in this algorithm, the minimum required heat transfer area can be determined. The algorithm is solved numerically by Newton-Raphson method. The results demonstrated that RDA-designed with twisted tape and nanolfuid provide higher efficiency compared with the traditional heat exchangers with in such that the design needs a lower heat transfer area for a given heat load.