Our other manuscript has been accepted for publication in the Asia-Pacific Journal of Chemical Engineering (Impact factor: 0.797) published by Wiley; a journal on chemical-engineering related and specialised areas, particularly on the key areas of; Process Application (separation, polymer, catalysis, nanotechnology, ferrous metallurgy), Energy and Environmental Technology (natural resources, coal gasification, gas liquidation, air pollution control, water treatment, waste utilisation and management) and Food, Pharmaceutical & Bioengineering (biomaterials, bioprocess, biochemical engineering)
A facile method to prepare high-purity magnetite nanoparticles by electro–oxidation of iron in water using a pulsed direct current
Heru Setyawan, Fauziatul Fajaroh, Memik Dian Pusfitasari, Minta Yuwana, Samsudin Affandi
- A facile method for producing magnetite nanoparticles is proposed.
- The magnetite nanoparticles posses ferromagnetic properties with sizes 7-23 nm.
- The size can be easily controlled by adjusting pulsed parameters.
- The magnetite nanoparticles are stable up to 200°C.
High-purity magnetite (Fe3O4) nanoparticles were successfully synthesized via the electro-oxidation of iron in an aqueous system using a pulsed direct current (pulsed DC). The pure iron to be electro-oxidized was electroplated on a steel plate, which was then used as a sacrificial anode in the electrochemical system. The electrolyte used was demineralized water, either with or without added NaOH, which was used to vary the pH of the solution, between 7 and 10. We showed that the pulsed DC significantly enhanced the purity of the magnetite that was formed. The FeOOH impurities that are typically present when continuous DC is used were not observed. The particles produced using the proposed method were nearly spherical in shape. The size of the particles ranged from 7-23 nm depending on the conditions of synthesis, namely the pulse frequency, duty cycle, and pH. The magnetite nanoparticles exhibited ferromagnetic properties, with values of saturation magnetization ranging from 18 to 55 emu g−1. The results obtained from thermal gravimetric/differential thermal analysis (TG/DTA) revealed that magnetite was converted into maghemite at a temperature of approximately 200°C, and into hematite under further heating to 500°C.
Keywords: magnetite nanoparticles; electrosynthesis; pulsed direct current; aqueous systems.