Catalytic activity of non-spherical shaped magnetite nanoparticles in degradation of Sudan I, Rhodamine B and Methylene Blue dyes

The catalytic activity of non-spherical shaped Fe₃O₄ nanoparticles synthesized by low cost co-precipitation method was tested. It was presented, that magnetite nanoparticles can be used to degrade not only Rhodamine B and Methylene Blue, but above all cancerogenic azo dye – Sudan I. It was confirmed, that the degradation of Rhodamine B can be described by pseudo-zero-order kinetic model, whereas degradation of Methylene Blue by pseudo-first-order kinetic model. The degradation mechanism of Sudan I by photo-Fenton reaction was proposed. It was noted, that this double-stage process can be associated with hydroxylation of Sudan I and degradation of derivates, such as 4′‑OH‑Sudan I and 6‑OH‑Sudan I. Therefore, it cannot be simple describe by one kinetic model. The introduction of hydroxyl group results in an increase of the absorbance, which in turn is associated with hyperchromic effect.