Fabrication, characterisation and magneto-responsive performance of manganese ferrite nanospheres for fast separation of oil slicks from water surfaces

The achievement of oil/water separation, characterised by easy operation, low cost and low energy consumption, significantly impacts environmental protection and economic loss reduction. However, industry practitioners still face a considerable challenge. In this study, we reported an efficient, recyclable and environmentally friendly material that facilitates the rapid separation of oil slicks from water surfaces. This material, known as magne-torheological (MR) fluid, demonstrates promising capabilities. The manganese ferrite (MnFe2O4) nanospheres were synthesised through a simple solvothermal method, employing oleic acid for hydrophobic modification. The resulting MnFe2O4 nanospheres exhibited a hierarchical morphology, rough surface, well-defined meso-structure, high saturation magnetisation and superparamagnetic characteristics. These unique properties make the MnFe2O4 nanospheres suitable for incorporation into MR fluid and effective oil removal. The MnFe2O4 nanospheres-based MR fluid demonstrated magnetic field-dependent rheological properties, excellent sedimen-tation stability, remarkable oil-removal efficiency and favourable recycling performance. Thus, the developed MnFe2O4 nanospheres-based MR fluid can serve as an effective tool for removing oil slicks from water surfaces.