Environmental Application of Biogenic Magnetite Nanoparticles to Remediate Chromium(III/VI)-Contaminated Water
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چکیده
The physicochemical characteristics of biogenic minerals, such as their high specific surface area and high reactivity, as well as the presence of a bacterial carrier matrix make them interesting for various applications, for instance as catalysts, adsorbents, oxidants or reductants. The objective of this study was to examine the efficiency of biogenic magnetite nanoparticles (BMNs) produced by metal-reducing bacteria in removing chromium. Interactions between ionic Cr(III/VI) and BMNs were examined under different solution pH (pH 2 to pH 12) using different dose of BMNs (0 to 6 g/L). Chemically synthesized magnetite nanoparticles (CMNs) were used in experiments for comparison. Results showed that BMNs had higher Cr(VI) removal efficiency (100%) than CMNs (82%) with reaction time of 2 weeks. The lower the pH of Cr-contaminated solution and the longer the reaction time, the higher the Cr(VI) removal efficiency. The Cr(VI) removal efficiency by BMNs in Cr-contaminated groundwater was about 94% after reaction time of 2 weeks. BMNs coated with organic matter were more effective to lead adsorption of Cr(III) with electrostatic interaction (82%) and to prevent oxidation of Fe(II) within the magnetite structure than CMNs (13%). These results indicate that BMNs could be used to decontaminate ionic chromium in environmental remediation technologies.
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