Local iron ore identification: comparison to synthesized Fe3O4 nanoparticles obtained by ultrasonic assisted reverse co-precipitation method for Auramine O dye adsorption

The synthesis of nanoparticles has to turn out to be a matter of great interest in recent years due to their numerous advantageous properties and applications in several areas. In this study, iron oxide nanoparticles were synthesized via chemical reverse co-precipitation method from ferrous and ferric solutions using ammonium hydroxide as a precipitating agent under ultrasound irradiation. Meanwhile, a natural iron-ore was collected from an iron-ore career situated in the north-west of Tunisia and dried then crushed to minimize particle size. Thus, a comparative study between these iron oxides was carried out based on their physicochemical and optical properties. Therefore, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption isotherms, transmission electron microscopy, and energy-dispersive X-ray microanalysis were used to study physicochemical properties of these materials. UV-vis spectroscopy was used to investigate optical properties. Results show that both materials can be used as heterogeneous catalysts in the Fenton process and that the novel natural iron oxide is better than the synthesized one because of its more developed surface area, its low cost, and its abundance. Eventually, preliminary adsorption studies of Auramine O, as a model of anionic dye, onto these two materials have shown that natural iron oxide is more effective adsorbent than the synthesized nanoparticles with an adsorption rate of 99%. Adsorption process followed Langmuir type and pseudo-second-order kinetic, suggest monolayer adsorption and physisorption process.

Automated summary

This study compared the physicochemical and optical properties of iron oxide nanoparticles synthesized chemically and extracted from natural ore, showing that the natural iron oxide had better adsorption performance. Both materials can be used as catalysts in the Fenton process, with the adsorption process following Langmuir type and pseudo-second-order kinetic.