Nanofurry magnetic carbon microspheres for separation processes and catalysis: synthesis, phase composition, and properties

A new method is developed to synthesize magnetic carbon microspheres decorated with carbon nanofibers and iron nanoparticles (nanofurry microspheres) for separation techniques in chemistry and biology. Microspheres are synthesized by carbonizing polystyrene–divinylbenzene-based, iron-loaded ion exchange resins. The phase composition, magnetic properties, and surface area and morphology of these materials are characterized by various techniques. It is detected that superparamagnetic (SPM) magnetite is present in microspheres exclusively upon carbonization at 400–500 °C, elemental iron, both α- and γ-Fe, is the major component at 600 °C, and cementite dominates between 700 and 1000 °C. Nanofiber formation is observed to be pronounced at high temperatures. The synthesized carbon microspheres have high surface area (100–300 m2 g−1) and can be separated easily by a magnet or by filtration. Saturation magnetization of selected samples is obtained between 5 and 28 emu g−1, depending on the phase composition. The novel microcomposites are expected to be effective adsorbents or support materials in various chemical processes, for example in water and air cleaning, catalysis, and biotechnological separations. Preliminary experimental studies for Cr(VI) removal from water and for platinum deposition are provided.