A correlation of the adsorption capacity of perovskite/biochar composite with the metal ion characteristics.

LaFeO3/biochar composite is prepared by cellulose-modified microwave-assisted method at 450 °C. The structure is identified by Raman spectrum which, consists of characteristics biochar bands and octahedral perovskite chemical shifts. The morphology is examined by scanning electron microscope (SEM); two phases are observed, rough microporous biochar and orthorhombic perovskite particles. The BET surface area of the composite is 57.63 m2/g. The prepared composite is applied as a sorbent for the removal of Pb2+, Cd2+, and Cu2+ ions from aqueous solutions and wastewater. The adsorption ability reaches a maximum at pH > 6 for Cd2+, and Cu2+ ions, and is pH-independent for Pb2+ ions adsorption. The adsorption follows pseudo 2nd order kinetic model, Langmuir isotherm for Pb2+ ions, and Temkin isotherms for Cd2+, and Cu2+ ions. The maximum adsorption capacities, qm, are 606, 391, and 112 mg/g for Pb2+, Cd2+, and Cu2+ ions, respectively. The electrostatic interaction is responsible for the adsorption of Cd2+, and Cu2+ ions on LaFeO3/biochar composite. In case of Pb2+ ions form a complex with the surface functional groups of the adsorbate. LaFeO3/biochar composite shows high selectivity for the studied metal ions and excellent performance in real samples. The proposed sorbent can be easily regenerated and effectively reused.