Combined antioxidant capped and surface supported redox-sensitive nanoparticles for continuous elimination of multi-metallic species

Abstract

A strategic modification involving (i) a multi-functional almond shell biochar surface support and (ii) capping with almond skin extracted antioxidants was performed to preserve redox-sensitive Fe⁰ nanoparticles (NPs). pXRD data showed generation of an iron-carbonyl shell on the supported Fe⁰ NPs (SA-Fe⁰), justifying successful antioxidant capping. The total metal removal capacity of 695 mg g⁻¹i.e. AsO₂⁻ (300.2 mg g⁻¹) > Cd²⁺ (224.2 mg g⁻¹) > CrO₄²⁻ (125.2 mg g⁻¹) > Ni²⁺ (44.5 mg g⁻¹) in batch mode, and 102 mg g⁻¹ in continuous column setup confirms the excellent reactivity of the SA-Fe⁰ nanocomposite. Loss of the iron-carbonyl shell and iron oxidation during interaction with contaminants confirm no hindrance in electron transfer due to antioxidant capping.