Graphycal Abstract: The magnetic materials were synthesised from pomelo peel (PP@Fe3O4), durian peel (DP@Fe3O4), and banana peel (BP@Fe3O4) for adsorption of Methylene Blue. Under the optimal conditions, adsorption efficiencies of 97.7%, 97%, and 98.9%, respectively. These materials were employed to assess the COD index in select water samples.