The main aim of this study was to evaluate the effi ciency of natural zeolite for Cr(VI) removal from aqueous solutions. Following simple modifi cation of adsorbent, the effect of operational parameters including pH (2-10), adsorbent dosage (2-20 g/L), contact time (5-150 min) and Cr(VI) concentration (10-50 mg/L) were studied according to one-factor-at-a-time procedure. The maximum Cr(VI) removal of 99.53% was obtained at initial pH of 2, contact time of 30 min, adsorbent dosage of 8 g/L and initial chromium concentration of 10 mg/L. The Freundlich isotherm was best fi tted with experimental data (R2 = 0.951). Also, type 1pseudo second order kinetic model showed the most correlation (R2 = 1) with the experimental data. According to obtained results, it can be concluded that the application of clay-like adsorbents such as natural clinoptilolite zeolite can be considered as an effi cient alternative for fi nal treatment of effl uents containing Cr(VI).
Soil is an important component of life cycle affecting agriculture and food crops. Quality of soil resources is defined according to their potential impact on human health by exposure of harmful constituents through the food chain. Heavy metals especially As, Pb and Cd are among the most hazardous elements which could be released to the top soil through different wastewaters, fertilizers, herbicides and etc. In this research Aghili plain in Khuzestan province, Iran was selected as a total of 54 samples were prepared based on a systematic gridding procedure. Selected heavy metals concentrations were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and then zoning was performed using kriging method. Pollution level was assessed through single factor indices and pollution load index. A separate map dealing with each heavy metal was prepared to present the distribution of heavy metal in Aghili plain. In all samples the heavy metals concentrations were followed the bellow trend: Pb>As>Cd.Furthermore, based on the PLI, all stations were categorized as moderately to highly polluted sites (1
Landfill leachates contain a wide variety of pollutants such as organic matter, refractory compounds, ammonia, particulate and dissolved solids and hazardous metals requiring application of advanced and well designed treatment processes before release to the environment. The main purpose of this research was to evaluate the efficiency of combined air stripping, Fenton oxidation and biological treatment in treating landfill leachate, especially the elimination of ammonia and refractory organics. The laboratory scale set-up consisted of three sequential but separate steps. The optimum conditions for air stripping and the Fenton oxidation were determined for landfill leachate from Karaj city, Iran. The final step was a moving bed bioreactor with HRTs of 18, 12 and 6 h. The highest NH(3)-N removal was 79% in the air stripping process at pH 10.5. At the optimum conditions for the Fenton reaction at a reaction time of 90 min, pH 3 and a H(2)O(2)/Fe(2+) mass ratio of 20, the COD removal was 61% and improved the BOD/COD ratio from 0.42 to 0.78. The overall COD removal including the final biological reactor with a HRT of 6 h resulted in an effluent COD concentration of less than 100 mg L(-1).
Background: The aim of this study was to determine the concentrations of lead (Pb) and cadmium (Cd) in lipstick and eye pencil cosmetics of different grades in the markets of Iran. Methods: This descriptive study was conducted in Ahvaz city in 2018. Sixty different samples of lipstick and eye pencil of three common brands were selected and analyzed using the Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES) and the results were compared with standard values recommended by the Food and Drug Administration (FDA). The analysis of lipsticks was based on producer country and colors and producer country only for eye pencil. Results: The mean concentrations of Pb and Cd were 41.86 and 53.42 µg/g, respectively. Concentrations of lead were higher than those of Cd in lipsticks, while for eye pencil, Cd showed higher concentrations. The overall results indicated that in all brands and colors of lipsticks, only 33% of the samples had Pb content less than the FDA limit, and among lipstick samples, 44% had Cd concentration less than the FDA limit of 3 μg/g, however, in 100% of the eye pencil samples, the concentration of Cd was higher than the recommended value of 3 μg/g. Conclusion: Given the health risks of exposure to heavy metals and in order to increase community awareness about the harmful effects of cosmetics, it is necessary to monitor the concentration of these toxic elements in these products and encourage the manufactures to meet the FDA standards.
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