Synthesis of γ-Fe2O3-ZnO-biochar nanocomposites for Rhodamine B removal

Abstract Organic dye molecules, for example Rhodamine B (RhB), cause a serious environmental issue in industry wastewater. Magnetic biochar adsorption is one of the effective ways for water treatment. In this work, we develop a facile technique to synthesize magnetic biochar γ-Fe2O3-ZnO-biochar nanocomposites by thermal decomposition of zinc(II) acetylacetonate and iron(III) 2,4-pentanedionate in the presence of biochar in triethylene glycol solvent under the protection of nitrogen. The synthesized magnetic biochar nanocomposites are characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and their adsorption performance on RhB is investigated. The adsorption capabilities of the nanocomposites are controlled by the ratios of zinc(II) acetylacetonate: iron(III) 2,4-pentanedionate: biochar, which provides an easy way to optimize the adsorption performance of the nanocomposites. The removal RhB tests indicate that magnetic γ-Fe2O3-ZnO-biochar nanocomposites exhibit improved performance than bare biochar. The improved performance is attributed to photocatalyst properties of ZnO in the composite. The developed method represents a novel strategy to prepare magnetic biochar nanocomposites with improved removal capabilities via photocatalyst nanoparticles toward wastewater treatment.