Surface-modified magnetic biochar: Highly efficient adsorbents for removal of Pb(11) and Cd(11)

Novel multi-functional magnetic biochar adsorbents have been synthesized by functionalization with carboxylic acid, amine, amide and thioamide groups on the surface of activated biochar and immobilization with Fe3O4 NPs. Morphology and structure of the novel biochar adsorbents were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The prepared adsorbents have been applied in the removing of Pb(11) and Cd(11) from aqueous media using Langmuir adsorption isotherm. High adsorption capacity (61.25 mg/g Pb(11) and 53.75 mg/g Cd(11)) along with low cost, green synthesis, easy recyclability and high performance after five runs provided an applicable adsorbent for the practical treatment of Pb(11) and Cd(11)-contaminated wastewater. The spontaneous and endothermic nature of the adsorption process was further confirmed by thermodynamic parameters.