نشریه علوم و تکنولوژی محیط زیست
سال بیست و ششم شماره 8 (پیاپی 147، آبان 1403)

According to the statistics of the World Health Organization regarding the severe shortage of water in many countries of the world, water supply depends on the use of existing resources, and currently, desalination of sea water and oceans is the only solution to supply water for communities that are Water resources are accessible.Desalination of salt water can be done with two thermal and membrane methods, and research has shown that using membrane technology is a more efficient way to solve this crisis economically and environmentally. In this study, a comparison was made on the performance of conventional pre-treatment and membrane pre-treatment before desalination of sea water by reverse osmosis method. The water inlet the reverse osmosis membranes must be of suitable quality in terms of turbidity and other important indicators of membrane fouling.

 The method used to analyze plans includes technical indicators. In this study, two pretreatment systems were sampled. These examples are: (1) conventional pretreatment (2) UF pretreatment. Based on this, in the pilots used for a period of one year, the water quality in the inlet and outlet sections such as turbidity and SDI 15 were analyzed and the results were discussed for the final evaluation.

The average SDI15 index of filtrate during the study time provided by the conventional and UF systems were 5.5 and 1.5 respectively. The required level for reverse osmosis should not exceed SDI15 of 5. which was slightly higher than the appropriate level in the conventional purification method, thus the use of a cartridge filter can solve this problem. The average value of turbidity after conventional pre-treatment wad 0.97 NTU and the standard deviation of turbidity for sea water and filtered is 0.14 and 0.09, respectively. The average value of turbidity after ultrafiltration was 0.35 NTU and the standard deviation for seawater and filtered water is 0.26 and 0.10, respectively. There is a significant correlation between temperature and water yield in both filtration methods.  

 From the results obtained from this study, it can be concluded that membrane-based pretreatment is a suitable technological alternative to the conventional method. Membrane-based pretreatment can successfully replace the conventional pretreatment process.

The emergence of environmental problems and its increasing flow has been the subject matter of many researchers and experts in the environment domain. Providing a culture, focused on the enhancement of environmental culture, that needs to recognize the effects of principles and effective criteria on environment's culture.  

 In the present study, the aim is recognizing and revising the cultural rankings of some effective factors on knowledge, attitudes, positive behaviors and increasing the public culture for the better planning. The present study, involved a questionnaire about attitude, and analytically with certain degree of 95%. The considered sample, used by NCSS software, was four hundred people.

The results raised from the statistical analysis by SPSS software version 16 show that there is a meaningful and positive relation between the effective indexes on environmental culture (P<%5).

 The results also show that from 5 revised criteria in this study, there is a meaningful relation between the criterion of education with the indexes of attitude, the people's environmental knowledge and the criterion of job and their indexes of attitude and environmental behavior. Therefore, the managers and the responsible people in these two parts must go further to refine and enhance the people's environmental culture by different ways. It's also suggested that pay more attention on the effective factors on enhancement of environmental culture in future studies and the responsible organizations in cultural affairs go further to refine and enhance it.

The development of the agricultural economy causes pollution and negative effects on the environment. Given the growing need for food in developing countries and increasing agricultural production, it is expected that greenhouse gas emissions will increase due overuse of fertilizers and chemical pesticides and land use change. Therefore, it is necessary to study the relationship between agricultural sector growth and environmental pollution caused by the use of chemical inputs such as fertilizers and chemical pesticides.

 In the present study, using Tapio decoupling index, the relationship between agricultural production growth and pollution caused by the agricultural production process due to the use of chemical pesticides in the period 2018-2008 has been evaluated. For this purpose, based on the environmental performance index, several countries have been selected and grouped, and for each group, the pollution decoupling index from the growth of the agricultural sector has been calculated and compared. The studied countries were divided into 4 groups based on the environmental performance index and different states of the decoupling index for each group were analyzed.

The results showed that the status of the decoupling index in the fourth group was much more stable than other groups.

 Due to the high share of the agricultural sector in the pollution emission, the decoupling method can be used to assess the relationship between the growth of the agricultural economy and pollution in this sector. Assessing the decoupling of GDP makes it possible to examine the decoupling of the environment by considering aspects of social sustainability relative to economic development.

 By improving the performance of the heat exchanger, it is possible to reduce the size and production costs of the heat transfer, and this leads to a reduction in fuel consumption and better environmental protection. To this purpose, engineers have proposed several ways to increase the heat transfer. The heat transfer rate of a turbulent non-Newtonian fluid flow in a heat exchanger with partially porous media is numerically investigated in this paper. The effects of power-law index of the fluid and Darcy number on the heat transfer rate and thermal performance of turbulent flow are studied and compared to each other.

 The research model is simulated in the FLUENT computational fluid dynamics software using Finite Volume Method and the flow and energy equations are discretized up to the second order upwind.

The pseudo-plastic fluid has the highest heat transfer rate and thermal performance compared to Newtonian and dilatant fluids. According to the findings, the heat transfer rate and thermal performance increase with decreasing Darcy number. Investigation of the effect of non-dimensional porous layer area (S) on the Nusselt number and thermal efficiency in different Darcy numbers shows that, the Nusselt number has the highest value in S=0.9 and thermal efficiency has the highest value in S=0.76.

 S=0.76 is the optimal porous layer thickness. Therefore, porous layer with S=0.76,  and the pseudo-plastic fluid are recommended for the optimal thermal efficiency.

 Leaching of herbicides not only reduces their efficiency, but also increases soil and groundwater pollution. 2,4-D is a herbicide that can pollute soil and deep water. This experiment was conducted with the aim of investigating the effect of organic matter and soil texture on the permeability of 2,4-D herbicide through biological and canonical correlation analysis.

 In this experiment in 2018 in order to analyze and rely on organic matter and soil texture effects on the 2,4-D leaching, Bioassay and Canonical Correlation Analysis techniques were used. Experimental factors were soil organic matter (control, 2.5 and 5 weight percent of sheep short dung), soil texture (control, silty loam and loam soil) and herbicide dose (1.5 and 3 L ha-1). After supplying treatments, polyvinyl chloride pipes benefited for soil retention then herbicide inoculated with distilled water on the soil column. After three days all each 2-cm rings of column soil were exposed to bioassay test.

According to seedling wet weight of cucumber (test plant) in the most amount of dung fertilizer treatment, herbicide leaching front estimated till six cm depth. Whereas this horizon measured 10 cm for the control soil. In sandy soil too, wet weight loss was measured until 12 cm soil depth. In other words, with decreasing organic matter and increasing soil porosity, 2,4-D penetration raised as 6 cm depth.

 Dung fertilizer and heavy soil lead to herbicide immobility and 2,4-D application is not suitable in the young gardens with shallow roots.

 Daphne macronata is one of the species of Daphne genus in Iran that has unique biological properties and has been used as a medicinal plant for a long time. In this study, biocompatible polymer nanofibers from polyvinyl alcohol and Daphne macronata plant extract were prepared as an antimicrobial coating with high efficiency by electrospinning method and its antimicrobial properties on gram-positive, gram-negative and the fungus was examined.

 In this study, a polymer solution with weight / weight of 12% polyvinyl alcohol polymer was prepared and 2 mL of plant extract was added to 10 mL of polymer solution. In order to prepare nanofibers, the optimal conditions of the electrospinning device including voltage of 17 kV, solution injection rate of 3 mL / h, nozzle head to collector distance of 7 cm and collector speed of 100 rpm were set.

After preparing the polymer layer, the morphology and diameter of the nanofibers were determined by scanning electron microscopy and the average diameter of the nanofibers prepared under optimal conditions was 80 nm. Examination of the antimicrobial activity of this coating showed that this structure shows a significant antimicrobial effect on bacteria, so that the highest antimicrobial effect was observed on the gram-positive bacterium Streptococcus pyogenes with a growth inhibition zone diameter of 14 mm.

 The nanocoatings obtained in this study can be used as an antimicrobial coating in the biological and medical fields for packaging or wound dressing due to their biocompatible, non-toxic, inexpensive and high efficiency structure.

In the contemporary era, environmental challenges such as water scarcity, climate change, and the imbalance between population and natural resources have drawn the attention of both governments and nations to the issue of the right to a healthy environment and environmental justice. The human rights dimensions of environmental issues have given rise to a phenomenon known as "greenwashing." Greenwashing refers to the use of environmental protection and human rights measures as a cover for destroying the ecosystem of a region and displacing its inhabitants in order to achieve certain colonial goals, such as the neo-colonial replacement of countries. This article employs a descriptive and analytical approach to examine how greenwashing leads to the violation of solidarity rights. Focusing on the destructive actions of the Zionist regime on the environment of occupied Palestinian territories, this research concludes that contemporary neo-colonialism, in the guise of greenwashing, not only makes colonial actions untraceable but also attracts the support of international and regional organizations.

Nowadays, due to the reduction of energy resources and the importance of the use of renewable energies as a substitute for fossil fuels in order to reduce environmental pollutants, the use of solar equipment has become increasingly important. Solar air collectors are one of these systems that use corrugated and wavy plates to increase their efficiency. In this research, Computational Fluid Dynamics (CFD) has been used to study the heat transfer and airflow inside a solar air collector that uses a corrugated absorber plate.

 In this work, the Reynolds number and the geometrical parameters of the corrugated shape on the absorber plate are considered design variables, and the simulation was done in two dimensions with Ansys Fluent 15 software. The Reynolds number changes in the range of 3800 to 18000 and the process of corrugated repeating and corrugated angle with the plate was selected as parameters affecting the geometry of the channel.

According to the investigations carried out, it has been shown that the best turbulence model is the k-ε RNG model. It was observed that the turbulence created by the corrugated plate leads to an increase in heat transfer within the duct. Although the corrugation of the plate also increases the pressure drop. The current CFD analysis clearly shows that the average Nusselt number and the average friction coefficient increase with the increase in relative pitch and relative height.

 Optimum performance conditions were calculated using the thermal enhancement factor. The maximum value of 0.98 was obtained for the coefficient of thermal improvement over the range of parameters studied.