Macroporous Magnetic Iron Oxides and Their Composites for Liquid-Phase Catalytic Oxidation
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Macroporous Magnetic Iron Oxides and Their Composites for Liquid-Phase Catalytic Oxidation E. K. Papynova, b, *, A. D. Nomerovskiia, A. S. Azona, V. O. Glavinskayaa, I. Yu. Buravleva, b, A. V. Ogneva, A. S. Samardaka, A. N. Dran’kova, S. G. Krasitskayaa, and I. G. Tananaeva, c, d aFar
Eastern Federal University, Vladivostok, 690091 Russia Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok, 690022 Russia c Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, 119991 Russia d Ozersk Technological Institute, Branch of NRNU MEPhI, Ozersk, 456780 Russia *e-mail: [email protected]
b
Received June 5, 2020; revised June 18, 2020; accepted June 20, 2020
Abstract—A novel synthetic approach is proposed to the production of macroporous magnetic iron oxides and their iron aluminate composites for liquid-phase catalytic oxidation. The materials were prepared by sol– gel synthesis where metal precursors were mixed with a colloidal template solution based on siloxane–acrylate latex. The pore structure and magnetic properties of the composites were studied as functions of temperature and magnetic field. The effects of the heat treatment schedule on the phase composition, porosity, and catalytic properties of the materials were elucidated. The results are supported by scanning electron microscopy, X-ray powder diffraction analysis, nuclear gamma resonance, and low-temperature nitrogen adsorption. The addition of aluminum ions in the course of sol–gel (template) synthesis allows the materials to preserve their pore structure upon high-temperature treatment, thereby improving the catalytic properties and significantly affecting the magnetic characteristics of the resulting magnetic composites. Keywords: sol–gel technology, template synthesis, macroporous materials, iron oxides, catalysis, aluminum nitrate, sodium aluminate, magnetic properties DOI: 10.1134/S0036023620110157
INTRODUCTION Advanced liquid-phase catalytic oxidation technologies constitute the basis for the purification of waste, industrial, and domestic water from high-toxicity hazardous organic pollutants that are not naturally biodegradable [1, 2]. The advantages of these technologies are due to their low operating costs, environmental safety, and the efficiency in removing such complex pollutants as organometal complexes with radionuclides, which are formed in the technical waters of nuclear power plants [3]. This is just the case where, according to [4, 5], oxidative catalysis is one of the most constructive solutions for recycling liquid radioactive media using oxide catalysts. The abovecited works show that, regardless of the efficiency of state-of-art oxidation catalysts, there is always a need to develop new catalytically active oxide systems with higher performances than the state-of-art analogues. Of the state-of-art catalysts, iron oxides are, for example, of interest; they are a promising alternative because of their low toxicity,
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