Removal of arsenic from water using iron-doped phosphorene nanoadsorbents: A theoretical DFT study with solvent effects

Abstract

Abstract Arsenicals are toxic compounds affecting human and animal health due to its high toxicity, where As(III) is more toxic than As(V). To find effective methods for As(III) removal from water, density functional theory calculations were implemented to expands the use of phosphorene based materials for the As(III) adsorption. It is shown that As(III) form bi(mono)dentate inner-sphere surface complexes with Fe-doped phosphorene nanoadsorbents in water at room temperature, where an adatom doping scheme reaches the highest adsorption stability. The interaction is chemical and energetically dominated by permanent electrostatics, polarization and charge-transfer stabilizing effects. The adsorption efficiency remains stable in the presence of water molecules from acid to neutral pH; while, alkaline solutions could be used for the regeneration of the nanoadsorbents. Further analyses also show the proposed nanoadsorbents could be implemented for the directly and simultaneously removal of As(III) and As(V) from contaminated water, where energy-saving is achieved by avoiding the pre-oxidation process to convert As(III) into As(V). Therefore, Fe-doped phosphorene emerges as a useful material for arsenic remediation.