Cobalt ferrite as an electromagnetically boosted metal oxide hetero-Fenton catalyst for water treatment

Abstract

The cobalt ferrite Fenton catalysts were obtained by the flow co-precipitation method. FTIR, XRD, and Mössbauer spectroscopy confirmed the spinel structure. The crystallite size of the as-synthesized sample is 12 nm, while the samples annealed at 400 and 600 °C have crystallite sizes of 16 and 18 nm, respectively. The as-synthesized sample has a grain size of 0.1–5.0 μm in size, while the annealed samples have grain sizes of 0.5 μm–15 μm. The degree of structure inversion ranges from 0.87 to 0.97. The catalytic activity of cobalt ferrites has been tested in the decomposition of hydrogen peroxide and the oxidation of caffeine. The annealing of the CoFe2O4 increases its catalytic activity in both model reactions, with the optimal annealing temperature being 400 °C. The reaction order has been found to increase with increasing H2O2 concentration. Electromagnetic heating accelerates the catalytic reaction more than 2 times. As a result, the degree of caffeine decomposition increases from 40% to 85%. The used catalysts have insignificant changes in crystallite size and distribution of cations. Thus, the electromagnetically heated cobalt ferrite can be a controlled catalyst in water purification technology.