Environmental Application of Biogenic Magnetite Nanoparticles to Remediate Chromium(III/VI)-Contaminated Water
Abstract
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 (Fe3O4) nanoparticles (BMNs) produced by metal-reducing bacteria in removing chromium.
In order to produce BMNs, the metal-reducing bacteria (Geocha-1) enriched from intertidal flat sediments in S. Korea were grown with akaganeite (β-FeOOH) as an electron acceptor, and glucose as an electron donor. The BMNs were harvested via washing and freeze-dry processes. Interactions between ionic Cr(III/VI) and BMNs were examined under different solution pH (pH 2 to 12) using different dose of BMNs (0 to 6 g/L). Chemically synthesized magnetite nanoparticles (CMNs) were used in experiments for comparison. Mineralogical characterization of BMNs was performed by XRD and TEM-EDS analyses. And XPS and ICP analyses were used to determine the amount of Cr(III/VI) removed after reaction. The BMNs were spherical in shape and around 10 nm in size. The surface area of the freeze-dried BMNs was measured to be 101 m2/g. Unlike CMNs, the BMNs were coated with organic matter containing an abundance of reactive carboxyl groups (-COOH). 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.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H21M1846R
- Keywords:
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- 0409 Bioavailability: chemical speciation and complexation;
- BIOGEOSCIENCESDE: 1832 Groundwater transport;
- HYDROLOGYDE: 1865 Soils;
- HYDROLOGYDE: 1871 Surface water quality;
- HYDROLOGY