Novel Bimetallic Magnetic Nanocomposites Obtained from Waste-Sourced Bio-based Substances as Sustainable Photocatalysts.

• Bio-based substances from waste as C sources for preparing bimetallic catalysts. • HO • generation is higher for Fe-Cu materials treated at higher temperature. • The nanocomposites catalyze the sunlight-driven degradation of carbamazepine. • The photocatalytic efficiency increases with decreasing amount of organic matter. Magnetic Fe-Cu nanocomposites with photocatalytic properties were prepared via the precursor method under different conditions using bio-based substances isolated from urban waste (BBS) as carbon sources. The effects of the amount of organic matter, the target temperature of the pyrolysis treatment (400–800 °C), and the replacement of Cu 2+ with Ni 2+ and Co 2+ on the structure, morphology, and photocatalytic capacity of the nanocomposites were analyzed. The capacity of the nanocomposites for the generation of hydroxyl radical under simulated solar irradiation was evaluated via EPR experiments. Carbamazepine (CBZ) photodegradation assays showed an increase of the photocatalytic efficiency of the nanomaterials with decreasing amount of BBS and increasing temperature of the pyrolysis treatment employed in the synthesis. Fe-Cu samples pyrolyzed at 600 and 800 °C showed a CBZ degradation larger than 70% after 4 h at pH 3 and 5. Lower photocatalytic efficiencies were obtained for the Fe-Ni and Fe-Co nanocomposites.