In this study, nanomaterials, iron oxide nanoparticles (Fe3O4), iron oxide nanocoated with citric acid (CA MNP) and iron oxide inlaid with wheat shells (WH MNP) were prepared and used under conditions such as pH, equilibrium time) and were studied on heavy cobalt as a pollutant, the nanomaterial was diagnosed by XRD analysis and FTIR infrared spectroscopy. Where the results of the removal Fe3O4 at the equilibrium time in the 10th minute and by 97.91%, while in CA MNP in the 10th minute, it gave a removal rate of 65.52%, while at WH-MNP in the 10th minute, it gave a removal rate of 95%. As for the results of the pH function Fe3O4 at PH 10 with a removal rate of 70.85%, either in CA-MNP at PH 8 with a removal rate of 95.97%, and in WH-MNP at PH 2 with a removal rate of 74.54%. The results of the concentration were in Fe3O4 at a concentration of 30 with a removal rate of 95.6%, while CA-MNP at a concentration of 30 with a removal rate of 77.62%, and in WH-MNP at a concentration of 30 with a removal rate of 96.6%. In XRD analysis, the grain size of Fe3O4 was calculated at (15.29) nm, CA-MNP was nm (15.78) and WH-MNP was about nm (17.14). The FTIR analysis of Fe3O4 shows the appearance of beams of the O-H and HOH group, while CA-MNP indicates that citric acid envelops the manganite surface by chemical adsorption of carboxylate strite ions in the acid, while WH-MNP is the hydroxyl group that indicates the vibration of C=O.