Effect of Fe (III)/Fe (II) cation molar ratio variation on magnetite Fe₃O₄ nanoparticles synthesized from natural iron sand by co-precipitation method

In this study, Fe₃O₄ nanoparticles (NPs) were synthesized using Indonesian iron sand via co-precipitation. One of the critical parameters in the formation of Fe₃O₄ by using the co-precipitation method is controlling the ratio of Fe (II)/Fe (III) during the reaction process. The impact of Fe (II)/Fe(III) cation molar ratio (1.5:1, 2:1, 2.5:1) on NP yield and crystallite size have been investigated. Actual yields were consistently lower than theoretical predictions, suggesting Fe (II) oxidation during synthesis. Notably, varying Fe (II)/Fe (III) ratios had minimal influence on nanoparticle crystallite size and overall product characteristics were observed.