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

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-1 i.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.