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Showing 2 results for Hexavalent Chromium
Volume 1, Issue 1 (3-2023)
Abstract
The dust produced by the electric arc method in the ferrochrome factory contains high amounts of hexavalent chromium, which has a high solubility in water and causes high environmental pollution. The present research has proposed a new method for neutralization of hexavalent chromium present in ferrochrome dust in solution environment by using chemical precipitation method. After checking conventional and non-conventional additives for neutralization by co-precipitation method, Iron sulfate is added to the aforementioned wastewater before release into the environment as a reducing agent of hexavalent chromium to trivalent chromium. Next, calcium sulfate was used as a stable complex forming factor in the system to remove chromium. XRD and XRF analyzes were used to characterize the dust and UV-Visible to determine the amount of chromium removed from the wastewater. The results showed that for 100 g/l of dust dissolved in water, adding 30 g of iron sulfate in the first stage and 20 g of calcium sulfate in the second stage reduces the content of hexavalent chromium from high values to below 10 ppm. Easy, high speed, cheapness and availability of additives are the merits of this method.
N. Salmani , M.h. Sayadi, M.r. Rezaei ,
Volume 9, Issue 2 (9-2018)
Abstract
Aims: Chromium has destructive effects on the environment and various chemical methods have been investigated for removal of Cr (VI), but high cost and environmental problems have led to using biological methods to remove chromium. The aim of this study was to optimize adsorption process of Cr from aqueous solution, using biosynthesized palladium nanoparticles by Spirulina Platensis.
Materials and Methods: In this experimental study, palladium nanoparticles were synthesized, using Spirulina Platensis and examined by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) methods. During the process of adsorption of chromium, pH, contact time, initial Cr concentration, and adsorbent dosage to optimization were optimized. Adsorption isotherms for Chromium were also determined on palladium nanoparticles based on Langmuir and Freundlich isotherm models.
Findings: The extract of Spirulina Platensis had the ability to synthesize palladium nanoparticles. The maximum removal was obtained at pH=2, initial chromium concentration=0.1mg/l, contact time=20 minutes, and adsorbent dosage=0.5g/l, and the removal percentage varied from 68.9% to 98.1%. RL for palladium nanoparticles was in the range of 0.17 to 0.95, showing that Langmuir model was suitable for adsorbent.
Conclusion: Biosynthesized palladium nanoparticles by Spirulina Platensis high efficiency in removing chromium in aqueous solutions.
