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Sulfidation of Zero-valent Iron Nanoparticles for Environmental Remediation

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Version 1 2021-12-07, 14:47
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posted on 2023-09-26, 23:58 authored by Berger, Amanda

The ability of nano-sized zero-valent iron (nZVI) to remove environmental contaminants, from heavy metals to polyhalogenated hydrocarbons, has been well established. However, the reactivity of nZVI towards contaminants is hampered due to competing for side reactions with oxygen and water. Sulfidemodified nZVI (S-nZVI) has become a viable option as S-nZVI has been shown to reduce organic compounds such as trichloroethylene faster than nZVI while also maintaining an increased resistance to oxidation by water. The Fulton group has established that nZVI supported on a naturally occurring microsilicate (Microsilica600, or “misi”), from a Rotorua geothermal deposit, is capable of removing nitrates from water. This material, or nZVI@misi, minimises the potential bioaccumulation path that nZVI has, and is easier to handle than unsupported nZVI. This research investigated the effect of sulfidation of nZVI@misi (or S-nZVI@misi) on the reactivity towards the degradation of a variety of different potential contaminants.  S-nZVI@misi was synthesised using sodium thiosulfate for sulfidation. Increasing the concentration of the reagent and sulfidation time from 3 hours to 24 hours resulted in high percentages of sulfur-to-iron (S/Fe) for each material. This increase in S/Fe had a significant impact on the removal of cadmium and chromium as with higher the percentage of S/Fe, the faster the removal of these species occurred. Compared to pristine nZVI@misi, S-nZVI@misi was significantly faster at removing both cadmium and chromium. However, sulfidation of nZVI@misi proved to reduce the rate of 4-nitrophenol reduction and prevent nitrate reduction from occurring. Experimental analysis also showed that cadmium removal was faster with S-nZVI supported by FeOOH-coated microsilica, compared to material supported by un-coated microsilica. Therefore, we have synthesised supported S-nZVI that quickly removes cadmium and chromium from solution compared to standard supported nZVI.

History

Copyright Date

2019-01-01

Date of Award

2019-01-01

Publisher

Te Herenga Waka—Victoria University of Wellington

Rights License

CC BY-NC-ND 4.0

Degree Discipline

Chemistry

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level

Masters

Degree Name

Master of Science

ANZSRC Type Of Activity code

1 PURE BASIC RESEARCH

Victoria University of Wellington Item Type

Awarded Research Masters Thesis

Language

en_NZ

Victoria University of Wellington School

School of Chemical and Physical Sciences

Advisors

Fulton, Robin