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

Abstract

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.

Hydrolytically stable nanosheets of Cu–imidazolate MOF for selective trapping and simultaneous removal of multiple heavy metal ions

“…3e) suggests that the metal ion adsorption process favours M 2+ ions existing in a more complex R–NH 2 M 2+ form, implying that the process is dominated by covalent complex formation between the amine group present in the framework and the metal ions, as opposed to electrostatic interactions. 38–40 To understand the affinity of the different metal ions to the Cu–Im MOF, distribution coefficients ( K D ) were calculated and Log K D versus adsorbent concentration plots were generated (Fig. 3a–d).…”