Bimetallic Oxide Nanohybrid Synthesized from Diatom Frustules for the Removal of Selenium from Water

Frustules or the rigid amorphous silica cell wall of unicellular, photosynthetic microalgae with unique porous architecture has been used to synthesize a composite by immobilizing zirconium and iron oxides on its surface and in the pores. This was effective for removal of Se from water, which is an emerging contaminant that is a micronutrient at low concentrations but toxic at high concentrations. The adsorption isotherms followed both Langmuir and Freundlich models, and the composite was regenerable. The Langmuir maximum adsorption capacity for Se(IV) (qm) was 227 mg/g, which is among the highest ever reported. The research findings highlight the synthesis of bimetallic composite as well as the potential of diatoms as hosts for nanomaterials for use in water treatment.