Magnetically-modified natural biogenic iron oxides for organic xenobiotics removal
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Biogenic iron oxides have been collected from a water stream and subsequently magnetically modified using water-based magnetic fluid. Both natural and magnetically modified materials have been characterized in detail using wavelength dispersive X-ray fluorescence spectrometry, X-ray powder diffraction, Mössbauer spectroscopy, electron microscopy and BET surface area measurements. The natural material is composed of 2-line ferrihydrite, forming hollow microtubules—sheaths of Leptothrix ochracea, and detrital components. As a result of the ferrofluid modification, maghemite nanoparticles were identified on the surface of the treated material. The active surface area of the bulk, magnetically-modified sample was 148 m2 g−1. The magnetically modified material was tested as inexpensive magnetically responsive adsorbent for the removal of selected organic xenobiotics, namely organic dyes, from aqueous solutions. The observed maximum adsorption capacities ranged between 34.3 and 97.8 mg of dye per 1 g of adsorbent.
KeywordsBiogenic iron oxides Leptothrix ochracea Magnetic fluid Magnetic adsorbents Xenobiotics
The authors thank to Klara Safarova for electron microscope characterization of the studied samples and Jiri Pechousek for surface area measurement. This work was supported by the research Projects LH11111 and LH12190 (Ministry of Education of the Czech Republic), 13-13709S (Grant Agency of the Czech Republic), Grant from the Technology Agency of the Czech Republic “Competence Centres” (Project TE01020218), by the Operational Program Research and Development for Innovations—European Social Fund (CZ.1.05/2.1.00/03.0058) and by the Joint Research Project FY2011 in the JSPS Bilateral Programs, supported by Ministry of Education, Culture, Sports, Science and Technology of Japan. This study was also supported by JST, CREST. Ivo Safarik thanks the Japanese Society for the Promotion of Science for the financial support of his study stay in Japan in 2010.
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