نشریه کاربرد شیمی در محیط زیست
پیاپی 51 (پاییز 1401)

Antibiotics are one of the largest groups of medicinal compounds that are used in medicine and veterinary medicine. These compounds, despite having positive effects in preventing and treating diseases in humans and animals, also have adverse effects on the environment. Recently, the indiscriminate use of antibiotics and the subsequent entry of these compounds into the environment have led to an increase in concerns at the global level. These compounds are not traditionally considered environmental pollutants, however, there are concerns about the emergence of these compounds in aquatic systems, due to their biological effects and potential risks to the environment and health. It is human. Conventional water and wastewater treatment processes are not designed to remove small amounts of chemicals such as antibiotics. Therefore, the entry of these compounds into the environment from different sources leads to the pollution of plants, animals, and water and soil environments and also creates problems for public health. In addition, the presence of these medicinal compounds in the environment leads to the development of antibiotic-resistant pathogens that potentially threaten the functioning of the ecosystem and human health. Then, the occurrence and the ways of their entry into the environment, as well as the negative effects of antibiotics on the environment and human health, were surveyed. Finally, the topics related to their fate and management and risk assessment of antibiotics in the environment were studied.

In this study, Melphalan interaction with graphene quantum dots was evaluated by infra red (IR), natural bond orbital (NBO) and frontier molecular orbital (FMO) computations. The negative values of adsorption energy, enthalpy changes, Gibbs free energy variations showed melphalan adsorption on the surface of graphene quantum dots is exothermic, spontaneous and experimentally feasible. Structural parameters including the energy of HOMO and LUMO orbitals, bandgap, electrophilicity, chemical potential, chemical hardness, density and zero-point energy were also calculated and discussed. The remarkable decrease in bandgap after the melphalan adsorption on the surface of graphene quantum dots demonstrated that the electrochemical conductivity and electrocatalytic properties increased after adsorbate interaction with the adsorbent and graphene quantum dots can be used for the construction of new electrochemical sensor in order to melphalan detection and quantitation. The remarkable decrease in bandgap after the melphalan adsorption on the surface of graphene quantum dots demonstrated that the electrochemical conductivity and electrocatalytic properties increased after adsorbate interaction with the adsorbent and graphene quantum dots can be used for the construction of new electrochemical sensor in order to melphalan detection and quantitation.

As living organisms, plants produce secondary metabolites as a means of adapting to various ecological conditions and phenomena around them in order to preserve themselves and future generations. Chamomile is a perennial and aromatic plant from the compositae family, whose height reaches about 15-60 cm. With yellowish-green leaves and yellow flowers, the dried leaves or its aerial parts have been used in the treatment of headaches, menstrual irregularities, insect bites, inflammations and wounds, and fever since ancient times. The general name of this plant is actually derived from the modified Latin word febrifugia, and despite the fact that different therapeutic doses of cow chamomile plant have beneficial effects in the treatment of separate groups of patients, the usefulness of its clinical effects is not a matter of consensus. Cow chamomile is available as fresh leaves, powdered and dried leaves, capsules and tablets, liquid extract, standardized dry extract, crystals and edible drops. The variety of cautionary predictions associated with study design, either the appropriate concentration of the substance or the duration of evaluation from previous clinical studies, make it difficult to obtain the set of beneficial effects of this herb. Despite the different reports of the usefulness of this plant in patients who are looking for a suitable alternative to prevent migraines.

PMA-AA hydrogel was synthesized by copolymerizing acrylic acid and maleic acid by free radical polymerization and using methylene bis acrylamide crosslinker and ammonium persulfate initiator. It is an efficient adsorbent for removing Cd2+ ions from wastewater. The resulting hydrogel was evaluated by infrared spectrometry and thermogravimetric analysis. The results of OH stretching vibration of AA and MA carboxylic functional groups showed a large and broad absorption band at 3000 cm-1. The C=O stretching frequency of the carboxyl group at 1631 cm-1 in PMA-AA hydrogel shifted to 1636 cm-1, these changes in frequency indicate that hydrogel adsorption is a chemical process. Thermogravimetric analysis of the unloaded PMA-AA hydrogel showed no weight loss up to 155 °C of the free gel, but at 190 °C, there was a significant weight loss, indicating hydrogel decomposition. This rapid weight loss for gels loaded with Cd2+ at 360°C indicated an increase in thermal stability of the loaded hydrogel. The maximum adsorption capacity for hydrogel -Cd2+ was determined to be 392.51 mg/g. The Langmuir isotherm provided the best explanation for the present result. This is because the surface of the hydrogel is homogeneous so its absorption is monolayer, the pseudo-second-order kinetic model explain the absorption well, and also the thermodynamic analysis shows that the absorption of Cd2+ on hydrogel is exothermic. The PMA-AA hydrogel loaded with Cd2+ ions was desorbed and still maintained the adsorption capacity of 99.30% after four adsorption-desorption cycles.

According to the statistical studies that were carried out in the Zylik mineralization zone, most of the samples collected from stream sediments show the concentration of arsenic (As) and antimony (Sb) higher than their Clarke concentration (Clarke number or clarke is the relative abundance of a chemical element, typically in Earth's crust). Also, according to the United States environmental protection agency (U.S. EPA) report, these values are higher than its standard for residential and industrial areas. According to the geochemical distribution map of these elements, the highest concentration of arsenic (As) is in the north and northeast and antimony (Sb) is in the north, south and east of the study area. It seems that this enrichment corresponds to the streams passing through the siliceous veins and caps in the north of the region. Therefore, this area can be the source of environmental contamination, which affects the ecosystem as a result.

The present study Impact of Corporate Social Responsibility Components on Environmental Costs in the Petrochemical Industry. This research is practical in terms of purpose and in terms of methodology, the correlation is of the causal type (after event). The systematic elimination sampling, 11 companies were selected as sample and were investigated in the period of 8 years between 2013 and 2020. The method used to collect information is a library and data are collected for measuring variables from the codal website and corporate financial statements and in Excel, basic calculations have been made then, to test the hypotheses of the software stata was used. The results of the research show that components of corporate social responsibility have an impact on environmental accounting in petrochemical industries. The components of corporate social responsibility have an impact on institutional pressures in petrochemical industries. The components of corporate social responsibility have an impact on green innovation in petrochemical industries. Corporate social responsibility components have an impact on environmental performance in petrochemical industries.