Optimizing and control of effective synthesize parameters for Fe3O4 nanoparticles using response surface methodology

To control Fe3O4 nanoparticles (Fe3O4 NPs) size, different molar ratio of Fe2+ and Fe3+ as well as ammonium hydroxide (pH) was used to synthesize Fe3O4 NPs through co-precipitation method. The Box-Behnken design was selected to explore the interaction between process parameters (factors) such as Fe2+ molar ion, Fe3+ molar ion and pH on the final size. The interactive effect between the process variables was evaluated by analysis of variance (ANOVA). The quadratic model predicted by the Box-Behnken design was significant with a P value of < 0.0001. The optimum synthesis conditions were predicted by the model indicating optimum size obtained using 1.00 mol Fe(2+ )ion with 3.00 mol Fe3+ ion with pH at 12.00. From the experiment, the particle size was 10 +/- 2 nm at optimum conditions, while the model predicted a particle size of 6.80 nm. The magnetic properties of Fe3O4 NPs were displayed typical ferromagnetic behavior with saturation magnetization value to be 49.729 emu/g. Finally, the optimized Fe3O4 NPs showed about 80% removal of Congo red (CR) dye, which confirms their applicability in adsorption process for future applications.