GREEN SYNTHESIS OF IRON OXIDE NANOPARTICLES

The present article deals with the problematic of so called green synthesis of iron oxide nanoparticles. The iron oxide nanoparticles can be used e.g. for catalysators and gas sensors or in MRI. The green synthesis is an innovative environmental friendly method which uses exclusively natural raw materials to obtain desired compounds. Fe(NO3)(3).9H(2)O was used as iron oxide precursor and red onion peel extract, green tea leaves extract and starch solution were chosen as precipitating agents in the present work. The shape, size and phase of resulting particles were investigated using scanning electron microscope and Raman spectroscopy. Through the green synthesis two different allotropic modifications of iron oxide nanoparticles were obtained. The use of starch and red onion peel extract led to formation of hematite while green tea leaves caused formation of mixture of hematite + maghemite. The average size of obtained hematite nanoparticles prepared using starch solution was (30 +/- 10) nm. The size of bean-shaped hematite nanoparticles prepared by using red onion peel extras was (130 +/- 40) nm length and (70 +/- 20) nm width. The mixture size of hematite + maghemite was measured on (100 +/- 20) nm length and (60 +/- 10) nm width.