نشریه کاربرد شیمی در محیط زیست
پیاپی 37 (زمستان 1397)

4 Nitro xylene is one of the dangerous and toxic compounds that enters water sources from the effluents of industries producing various insecticides and causes pollution of water reserves and the environment. In this paper, graphene oxide was used to remove the toxic compound of 4-nitroxylene from aqueous solutions by adsorption method. In this regard, the effect of various parameters such as initial concentration of 4 nitro xylene, contact time, initial pH, adsorbent dose and temperature on the removal of 4 nitrogen xylene was studied. The results showed that the adsorption process reaches equilibrium in 90 minutes. The removal rate of 4 nitro xylene increases with increasing adsorbent dose and temperature. the highest removal rate also occurred at pH = 7. however, increasing the concentration of 4 nitro xylene has an inverse relationship with the removal percentage, and increasing the concentration of 4 nitro xylene reduces the removal percentage. according to the results, 0.001 g of graphene oxide is able to remove 95.69% of 4 nitro xylene at an initial concentration of 10000 mg L-1 and at pH = 6.6 Therefore, graphene oxide is a powerful adsorbent to remove the toxic compound of 4 nitro xylene.

Today, pollution of water resources by petroleum compounds and its presence in the food chain is one of the environmental problems. Therefore, the removal of these compounds during the water purification process is very important. The aim of this study was to investigate the removal of benzene and toluene monoaromatic compounds by functionalized chitosan biopolymer. First, chitosan hydrogels were prepared. It was then functionalized with carbon nanotubes at three levels (zero, 10 and 20%). The influence of concentration and type of hydrogel, pH, contact time and different concentrations of BT on adsorption was investigated. The experiments have shown that nano-hydrogels prepared to remove BT from aqueous solutions. Chit /CNTS hydrogel with 20% nanotube is able to remove 500 mg/ 100 ml of the contaminant at a concentration of 200 mg/ l in 40 minutes at the inherent pH of the solution with the highest percentage.

Hydrogels are three-dimensional polymers that do not dissolve in water but swell. one of the most important physical properties of hydrogels is their swelling in water. Polyvinyl pyrrolidone has a wide range of applications due to its biocompatibility. methacrylic acid also has many uses due to its COOH group. In this project, using free radical polymerization at 65 °C for 5 hours and 45 minutes, using AIBN as an initiator and methylene bisacrylamide as a crosslinking agent, cohydrogels (vinyl pyrrolidone-methacrylic acid) were prepared and at different pH, temperature and intensity of ions were examined. The maximum inflation was obtained at pH = 12 and in the ratio of 1:1 equal to 8000% and the minimum inflation was obtained at pH = 2 in the ratio of 1: 2. FTIR was used for structural identification and T.G.A. for thermal identification, the maximum degradation for these hydrogels was at 75 ° C, due to high swelling.

Malva sylvestris is one of the most important plants used in pharmaceutical and cosmetic industries is the health of most developed countries. The juice is a potent anti-oxidant strong disinfectant. The leaves and flowers of this plant have a great application in the provision of Medicine and treatment in traditional medicine. In this research, Malva sylvestris was collected from the Anzan Meshgin-Shahr area in the northwest of Iran. The essential oil was extracted by Clevenger's apparatus, GC and GC/MS devices were used for analysis of essential oil compounds and accurate measurements of the compounds. Then, the effect of the essential oil of the Malva sylvestris and  control on the common bacteria of the oral infection evaluated in two ways: Disc deffusion And minimum inhibitory concentration (MIC). According to the results, the essential oil of the herb has a significant inhibitory effect on the types of gram negative and positive bacteria. Also, comparing the diameter of the non-growth of the plant with chlorhexin, it was found that the essence of the herb medicine showed relatively similar results to that of the chlorhexin.  According to the findings, essential oil of the herb has a good anti-microbial effect against the common bacteria of oral infections. As a result, the essential oil of this plant with different concentrations, after completing studies, can be an appropriate alternative for chemical drugs and chemical mouthwashes in the treatment of oral bacterial infections.

In the present investigation, HOMO-LUMO energy gap, polarizability, structural parameters, molecular mass, hardness, softness, chemical potential of the pyrimidine bases thymine, cytosine and uracil in the gas phase were calculated. Density Functional Theory calculations were performed by the B3LYP method with 6-311G basis set on the compounds. thymine, cytosine and uracil present polarizability of 70.45623, 64.75450 and 58.07109 a.u. at the B3LYP method, respectively. The HOMO–LUMO energy gap of 5.39343, 4.92623 and 5.56622 ev were obtained for the thymine, cytosine and uracil using B3LYP method, respectively. According to the calculations, HOMO–LUMO energy gap and hardness of uracil, polarizability of thymine, dipole moment and softness of cytosine in the gas phase have the largest values. According to the HOMO values, cytosine is more reactive in the reactions with electrophiles and according to the values of LUMO, uracil is more reactive against reactions with nucleophiles. N3 atom has the most negative charge and oxygen atoms have the highest electrical potential

In the present investigation, HOMO-LUMO energy gap, polarizability, structural parameters, molecular mass, hardness, softness, chemical potential of the pyrimidine bases thymine, cytosine and uracil in the gas phase were calculated. Density Functional Theory calculations were performed by the B3LYP method with 6-311G basis set on the compounds. thymine, cytosine and uracil present polarizability of 70.45623, 64.75450 and 58.07109 a.u. at the B3LYP method, respectively. The HOMO–LUMO energy gap of 5.39343, 4.92623 and 5.56622 ev were obtained for the thymine, cytosine and uracil using B3LYP method, respectively. According to the calculations, HOMO–LUMO energy gap and hardness of uracil, polarizability of thymine, dipole moment and softness of cytosine in the gas phase have the largest values. According to the HOMO values, cytosine is more reactive in the reactions with electrophiles and according to the values of LUMO, uracil is more reactive against reactions with nucleophiles. N3 atom has the most negative charge and oxygen atoms have the highest electrical potential.

Industrial activities are associated with many risks. Safety, health and environmental (HSE) assessments are very important in the industry due to accidents that lead to death or various disabilities. The results of HSE review and evaluation are an effective help for managers and engineers in deciding and designing health and safety systems in high-risk environments and prevent accidents. the purpose of this study, which is conducted for the first time, is to provide an approach to identify and rank and assess the risk of Pouya Zarkan Aq Dareh Processing Company by occupational safety analysis (JSA) using PHA-pro software. Necessary measures (including types of hazards and consequences) through observation methods, interviews with specialists and experts, review of documents and conditions of the study area, in order to reduce and control accidents and hazards caused by pollution and unsafe behaviors. the production line and the total of the factory have been done in order to determine the priority of the studied risks and consequences and finally by using the Occupational Risk Assessment (JSA) technique, occupational risk and safety assessment.