In this study, alpha-Fe2O3 nanoparticles (NPs) have been prepared using the hot water extract of the mandarin (Citrus reticulum) peels as a way for recycling of domestic waste to valuable product. The prepared hematite was characterized by UV/Vis spectroscopy, thermal gravimetric analysis, XRD, FTIR, SEM, and TEM. It was found to be porous irregular sphere shaped NPs with average size of 20-63 nm, characterized by weak ferromagnetic properties and band gap (Eg) of 2.38 eV. The prepared alpha-Fe2O3 NPs expressed good photocatalytic degradation activity. It showed good capacity for the decontamination of polluted water from anionic and cationic dyes and dicholorophenols under visible light irradiation.