Abstract:Removal of toxic metals from waste waters is one of the main concerns for environmental protection due to the high toxicity combined with their very long life span and slow biodegradability. Heavy metals such as Cr (VI) are very hazardous to the health of humans, flora and fauna because once they are absorbed into a living organism they are eliminated very slowly and become part of the food chain. The removal of such toxic materials has been tested through the use of magnetic nanoparticles in order to obtain a clean depollution of waste water. The comparison of two such materials, magnetite and maghemite was presented. The synthesis procedure for both materials was compared, their morphologies analyzed by XRD, TEM and SAED and their adsorption capabilities were evaluated at various pH values. The purpose of this study was to determine the differences in performance of the two magnetic nanopowders in terms of Cr (VI) removal from waste waters.