نشریه کاربرد شیمی در محیط زیست
پیاپی 54 (تابستان 1402)

One of the most important issues that all the countries of the world are dealing with today is the issue of energy supply. Energy supply is one of the most basic prerequisites for social development and economic growth of many societies, especially developing countries, and access to economically sustainable and environmentally friendly energy sources seems necessary in today''''s conditions. The decrease in fossil resource reserves and the increase in the price of oil and its products, as well as the need to pay attention to the reduction of environmental pollution caused by fossil fuels, have encouraged the countries of the world to use renewable and clean energies. Biofuels are one of the renewable resources that have attracted the attention of many European and American countries. Substitution of fossil fuels with biofuels has the potential to reduce some of the adverse environmental impacts of fossil fuel production and use, including emissions of conventional pollutants and greenhouse gases, depletion of finite resources, and dependence on unstable external suppliers. In addition to environmental benefits, the use of suitable biofuels can bring economic benefits such as reducing agricultural surplus reserves, reducing unemployment and dependence on imported oil, rural development, sustainable agriculture, etc. In the current study, after introducing and expressing the characteristics of two common biofuels, biodiesel and bioethanol, the general advantages and disadvantages of using biofuels, the economic, social and environmental considerations of using biofuels have been discussed.

The construction industry is more risky than any other profession. There are many dangers in the construction sites; But there are many ways to minimize these adverse events. Construction involves a lot of risk and employers know that managing of workers is difficult. When the employer decides to construct a building, he must arrange the necessary actions to prevent accidents, provide workers with safety equipment and give them the necessary training to prevent physical harm. In this research, the dangerous activities of construction works were assessed using the JSA method. Based on the opinions of the expert team, the range of numbers smaller than 10 is consider as low risk, the range of 10-12 is medium risk, and numbers above 12 high risk. Out of the total of 13 activities in the construction project, 5 incidents are high risk incidents, 5 incidents are moderate risk activities and 3 incidents are in the low risk range. After the corrective actions, high risk activities were removed and only 3 activities were included in the range of medium risks. The rest of the activities were considered in the safe zone.

In this research, the ability of solvent extraction to recover zinc from Zanjan Zn extraction unit waste samples has been investigated. This cake contained 180080, 26840, 141040 and 254090 ppm of sulfur, nickel, cadmium and zinc, respectively. Zinc extraction was performed using Cyanex 272 organic solvent. The investigated variables included pH (in the range of 0 to 1.5), time (in the range of 1 to 6 hours), temperature (60 to 80 °C) and the ratio of solids to solution (10 to 30%). Experiments were designed in Design-Expert software version 7 and using central composite design (CCD). pH was the most influential parameter and temperature was the least important parameter. The highest efficiency was measured with 100% at pH 0, temperature 80°C, ratio of solids to solution 30% and time 6 hours. The lowest zinc removal efficiency with 76.6% occurred at pH 1.5, temperature 60 and ratio of solids to solution 10% and time 3.5 hours. Considering the average zinc removal efficiency of 89.10%, the combination of using Cyanex 272 solvent and pH is a suitable method for extracting zinc from cold cake waste and this method has a high performance.

Polymeric materials that hold the capacity to reply toward exterior stimuli are denoted as stimuli responsive polymers or smart polymers. Smart polymers experience a great reversible change, either chemical or physical, in their properties as a significance of minor ecological differences. They can reply to a single, dual, or multiple stimulus such as the electric field, temperature, magnetic field, pH, light intensity, living molecules, etc. In this paper, the main objective is to elaborate the importance of smart polymers and their composite materials at the nano scale. Smart polymer classification along with the most familiar synthesis methods and some most common applications are briefly summarized in this paper. Some common applications of smart polymers are discussed here such as sensor/ biosensor, wastewater treatment, data storage devices, cancer therapy and surgery devices, drug delivery system, etc. The multidisciplinary exploration concerning very diverse disciplines will be essential to offer advances in smart polymer nanocomposite and their several types of application. Polymer chemists, organic/inorganic chemists, material scientists, ecologists, pharmacologists, and therapeutic specialists will have to work together toward realizing innovative materials to meet the requirements of the emerging modern civilization.

The smart mobile phone application can play a prominent role in chemistry education, provided that the application needed by the students is available. The current research has been carried out with the aim of assessing the needs, feasibility and pathology of the introduction of smart phones in the process of teaching and learning chemistry. This research is a basic research type and according to its purpose, it is a descriptive, exploratory type with contextualization method. The statistical population includes all chemistry students of Islamic Azad University, Ahar branch. The 9 students have participated in this research as an available sample. The findings of this research indicate that there is a need to include a smart phone in the chemistry education process from an educational and structural perspective. However, it is not possible to introduce a smart phone to the chemistry education process from the psychological and security aspect in the Islamic Azad University of Ahar branch, while the cultural aspect is acceptable. Also, based on the results of the Grounded Theory, the possible harms of the introduction of smart phones to the process of teaching and learning chemistry can appear in the form of educational, cultural, structural, psychological and security harms.

Pesticides are widely used to prevent unwanted attacks of pests on plants and agricultural fields. The uniqueness of their chemical structure or their interaction with the environment determines the nature of pesticides. In most cases, farmers and consumers of these products, although they know their serious effects, still cannot limit their consumption. Pesticides have harmful effects on soil and human ecosystems that affect molecules, tissues and biological organs and cause acute or chronic disorders. These disorders affect people of all ages, including during pregnancy. These pollutants affect aquatic systems when released. Water molecules in the river are affected by the accumulation of these toxic pollutants with alkaline pH and heavy metals, which can negatively affect the health of plants and animals. This article discusses the scientific literature on the various modification technologies available for safer pesticide use. The use of microorganisms and biological methods for the decomposition of chemical substances in the soil is monitored. However, the effectiveness of this method in the future to save the environment is debatable.