The adsorption of heavy metal ions (Cr3+, Pb2+ and Cd2+) by metal oxide monoliths (Fe2O3 and Fe2O3/SiO2) synthesized via nanocasting method using SiO2 monoliths as a template was studied. The adsorption experiments were performed in different batches by varying key parameters and the equilibrium between the adsorbents and metal ion solution was achieved in similar to 120 min at pH 6. The maximum monolayer adsorption efficiency for Pb (II), Cr (III) and Cd (II) ions was 850, 770 and 690 mg/g, respectively, for the magnetic Fe2O3/SiO2 monoliths. The experimental data show best fit with the pseudo-second-order reaction type. The adsorption data found to be well fitted using Freundlich and Langmuir adsorption isotherms. The adsorption process was exothermic and spontaneous in nature, as confirmed by the thermodynamic parameters. Furthermore, the photocatalytic degradation of an industrial dye e.g., remazol black XP (RxP) by Fe2O3/SiO2 monoliths was done from wastewater and the photocatalytic efficiency of the monoliths (using different amount) has been evaluated under visible light source which gives the best results (97.8%) for the monolith concentration 0.10 g/L. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.