Zero-valent iron nanoparticles (nZVI, Fe0 NPs) are capable of effectively degrading a broad range of environmental contaminants and have been extensively studied as a tool for groundwater remediation. However, Fe0 NPs agglomerate rapidly; this process can significantly decrease their effective surface area and thus significantly reduce their reactivity. To avoid such agglomeration, macroporous alginate substrate-supported Fe0 NPs (Fe0 NPs/MAS) were firstly synthesized by a two-part Fe0 NP-immobilization approach: 1) The fabrication of a macroporous alginate substrate (MAS) that provided a large surface area capable of sustaining a high load of stable and well-dispersed Fe0 NPs (26.06 wt.%). 2) A facile chemical reductive growth procedure to generate Fe0 NPs (ca. 50-100 nm) that are covalently anchored to the surface of the MAS. Batch experiments were further carried out to elucidate the efficiency of the Fe0 NPs/MAS toward nitrate removal from aqueous solution. Compositional and structural characterizations showed that the reductively grown hemispherical shaped-Fe0 NPs were covalently immobilized onto MAS mainly though Fe–O–C connections, which improved not only Fe0 NPs stability but also their reactivity. The Fe0 NPs/MAS removed &gt;96.5% of nitrates from an aqueous solution within 30 minutes, whereas unsupported Fe0 NPs that removed only 44.7% of nitrates over a longer period of time. These results demonstrate that the enhanced efficiency of Fe0 NPs/MAS is mainly due to agglomeration-prevention effect. On the basis of our experimental results, immobilization of Fe0 NPs through the alginate substrate-bound growth was expected to help develop practical applications for Fe0 NPs in environmental remediation, such as reactive media in permeable reactive barriers (PRBs) or an in-situ subsurface reagent.

Macroporous alginate substrate-bound growth of Fe0 nanoparticles: Synthesis, structural characterization and application in nitrate reduction

251st National Meeting (2016)

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