جستجوی مقالات مرتبط با کلیدواژه "gold mine" در نشریات گروه "زمین شناسی"

Cyanide is one of the most important and harmful pollutants released to the environment and as a result of industrial activities, aquatic environments are the most important route for exposure of living organisms to this pollutant. This research aimed to study the adsorption of cyanide by raw zeolite and modified zeolite with surfactant. Using the cationic surfactant of hexadecyltrimethylammonium bromide, the raw zeolite was modified. After the determination of prepared adsorbent properties and isothermal experiments, kinetics, the effect of pH, and the ionic strength of the stock solution was measured by batch tests. The XRD results confirmed the presence of clinoptilolite mineral in the structure of the raw zeolite and the surface coating of raw zeolite by surfactant after modification was observed by SEM images. The Langmuir, Freundlich and, Tamkin adsorption models showed an excellent ability to describe the cyanide adsorption isotherm using the studied adsorbent. The adsorption capacity of cyanide by modified zeolite was 3.97 mg /g, which is significantly increasing compared to the maximum adsorption capacity of raw zeolite cyanide (0.54 mg /g). Modelling of kinetic data showed that pseudo first-order and pseudo second-order models have an excellent ability to describe the adsorption kinetics of cyanide contaminants using natural and modified zeolites. Cyanide removal by surfactant-modified zeolite decreased with increasing pH and ionic strength of the stock solution. The results of this study showed that the modification of zeolite with surfactant could be used as a non-toxic and efficient adsorbent to remove cyanide from aqueous solutions in the bed of the tailings dams of the Zareshoran mine processing plant in Takab city of West Azerbaijan province of Iran.

The Hired mining area south of Birjand, South Khorasan province has been identified as the center of mineral pollution accumulation and it has been attempted to map the soils of the study area from their geochemical and environmental map. The maximum concentrations of Arsenic and Antimony were 5550 and 910 ppm, respectively. The enrichment factor (EF) for Arsenic, Antimony and Cadmium are 1.89, 2.05 and 0.03, respectively. This indicates the average contamination of the two elements Arsenic and Antimony and the lack of contamination of the area with Cadmium. According to the I-geo index, the degree of contamination of Arsenic and Antimony elements was 1, indicating a moderate contamination of the two elements in the region and less than 1 for Cadmium. Pollution Index (PI) for the Arsenic and Antimony elements in the area was moderate and for the Cadmium element, indicating that the soils of the study area were classified as non-polluted to moderately contaminated and most of this contamination is in the adjacent soils of the mine. In general, the soils of the study area have high levels of trace elements (above the natural background value) and if not controlled in the future, the pollution will reach a critical level and cause many problems for the inhabitants of the area.