1. Exfoliated graphite with γ-Fe2O3 for the removal of oil and organic pollutants from the water surface: Synthesis, Mossbauer study, sorption and magnetic properties.
- Author
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Ivanov, Andrei V., Volkova, Svetlana I., Maksimova, Natalia V., Pokholok, Konstantin V., Kravtsov, Alexei V., Belik, Alexei A., Posokhova, Svetlana M., Kalachev, Igor L., and Avdeev, Victor V.
- Subjects
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ORGANIC water pollutants , *MOSSBAUER effect , *MAGNETIC properties , *FERRIC oxide , *ENERGY dispersive X-ray spectroscopy , *GRAPHITE , *MICROPORES , *FERRIMAGNETIC materials - Abstract
Exfoliated graphite (EG) is a promising sorbent for oil and organic pollutants, which has a high sorption capacity and hydrophobicity. Modifying the EG with ferrimagnetic compound allows EG with sorbed oil to be collected from the water surface with the use of a magnetic field. The aim of this work is to obtain a sorbent based on exfoliated graphite with ferrimagnetic maghemite (γ-Fe 2 O 3) and investigate its structure and functional properties. The preparation of iron-containing EG includes the impregnation of expandable graphite with a FeCl 3 water solution and the thermal treatment of impregnated expandable graphite at temperatures between 400 and 1000 °C. Mossbauer spectroscopy, X-ray diffraction analysis, scanning electron microscopy and energy dispersive X-ray spectroscopy show the evolution of the iron-containing phase from FeOCl to the mixture of α-Fe 2 O 3 and γ-Fe 2 O 3 , which grants magnetic properties to the samples. EG obtained at 1000 °C has a saturation magnetization of 22.7 emu g−1. High macropore and meso-/micropore volume investigated by mercury porosimetry and nitrogen adsorption-desorption method results in a high sorption rate and sorption capacity of EG up to 30 g g−1 toward oil and liquid hydrocarbons. At the same time, the EG sorption capacity toward water is ten times lower. [Display omitted] • Exfoliated graphite/γ-Fe 2 O 3 is obtained from expandable graphite/FeCl 3. • Evolution of the iron-containing phase was investigated by Mossbauer spectroscopy. • Consequent formation of FeOCl, α-Fe 2 O 3 and γ-Fe 2 O 3 is observed. • γ-Fe 2 O 3 content increases when increasing the thermal treatment temperature. • EG/γ-Fe 2 O 3 has high saturation magnetization and oil sorption capacity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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