This work demonstrates the preparation of graphene-oxide (GO)–Fe3+ hybrids nanosheets and their high bleaching efficiency on the dye “Reactive Red 120 (RR 120)” by using sonocatalytic degradation. Sonocatalytic degradation was enhanced by using oxidants like PMS (peroxomonosulphate), PDS (peroxodisulphate), H2O2 (hydrogen peroxide) and KIO4 (potassium periodate). Our observations manifested that the degradation of the dye “RR 120” was found to be multiplied by addition of oxidants in the order of PMS > H2O2 > PDS > KIO4. The effect of inorganic ions was studied by the addition of SO42−, Cl−, H2PO4− and HCO3−. These results revealed that an addition of inorganic anionic decreases the degradation efficiency of RR 120 at high concentration. The trend of decreased degradation efficiency was SO−4 < Cl− < HPO4. In identical conditions, upon addition of HCO3−, the degradation rate of RR 120 degradation was increased. As-prepared GO–Fe3+ hybrid nanosheets were characterised by using X-ray diffraction technique, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, Raman spectroscopy and Energy Dispersive Analysis of Spectroscopy. Raman and XPS results confirmed the existence of Fe3+ ions in GO sheet.