Fabrication of magnetic biochar was done by pyrolysis of waste leaves of Raphanus sativus (MRB) and Artocarpus heterophyllus (MJB) peel pretreated with FeCl3 was examined for As(III and V) adsorption from an aqueous solution. The synthesized bioadsorbents were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), particle size analysis (PSA), scanning electron microscope (SEM), energy dispersive x-ray (EDX), zeta potential, Vibrating sample magnetometer (VSM) and point of zero charge (pHZPC). MRB-800 exhibits greater efficiency toward the removal of both As species with qmax value 2.08 mg/g for As(III) and 2.03 mg/g for As(V). Whereas, the qmax value was 1.13 mg/g for As (III) and 1.26 mg g-1 for As (V) adsorption using MJB-800. Temkin and Freundlich isotherm were best fitted to the adsorption of As(III) and As(V) by MRB-800, respectively. Langmuir isotherm was best followed to the adsorption of As (III and V) by MJB-800. Pseudo-second-order kinetics was well simulated by the experimental data of As adsorption using both the bioadsorbents. Surface complexation and electrostatic attraction was dominant mechanism for As (III) and As (V) adsorption. Thermodynamic study shows that removal of As (III) was exothermic while the As (V) adsorption was endothermic for MRB-800 and MJB-800.
Keywords: Biochar; adsorption; arsenic; mechanism; water treatment.
Based on the available literature, it was revealed that no work has been reported yet for the utilization of Raphanus sativus (Radish leaves) and Artocarpus heterophyllus (Jackfruit peel) waste for the preparation of magnetic biochar and its application for As(III) and As(V) removal for aqueous solution.