Hydrophilic sulfurized nanoscale zero-valent iron for enhancing in situ biocatalytic denitrification: Mechanisms and long-term column studies

So Yeon Yoon, Min Ji Kim, Hye Won Kim, Seon Hwa Lim, Choe Earn Choong, Sang Eun Oh, Jung Rae Kim, Yeomin Yoon, Jae young Choi, Eun Ha Choi, Min Jang

Research output: Contribution to journalArticlepeer-review

Abstract

The aim of this study was to investigate the effects of hydrophilic sulfur-modified nanoscale zero-valent iron (S-nZVI) as a biocatalyst for denitrification. We found that the denitrifying bacteria Cupriavidus necator (C. necator) promoted Fe corrosion during biocatalytic denitrification, reducing surface passivation and sulfur species leaching from S-nZVI. As a result, S-nZVI exhibited a higher synergistic factor (fsyn = 2.43) for biocatalytic NO3- removal than nanoscale zero-valent iron (nZVI, fsyn = 0.65) at an initial nitrate concentration of 25 mg L−1-N. Based on kinetic profiles, SO42- was the preferred electron acceptor over NO3- when using C. necator and S-nZVI for biocatalytic denitrification. Up-flow column experiments demonstrated that biocatalytic denitrification using S-nZVI achieved a total nitrogen removal capacity of up to 2004 mg L−1 for 127 d. Notably, microbiome taxonomic profiling showed that the addition of S-nZVI to the groundwater promoted the growth of Geobacter, Desulfosporosinus, Streptomyces, and Simplicispira spp in the column experiments. Most of those microbes can reduce sulfate, promote denitrification, and match the batch kinetic profile obtained using C. necator. Our results not only discover the great potential of S-nZVI as a biocatalyst for enhancing denitrification via microbial activation but also provide a deep understanding of the complicated abiotic-biotic interaction.

Original languageEnglish
Article number131197
JournalJournal of Hazardous Materials
Volume452
DOIs
StatePublished - 15 Jun 2023

Bibliographical note

Funding Information:
This work was supported by the Korea Environmental Industry & Technology Institute (Grant 2018002480006 ) and the National Research Foundation (NRF) of Korea, which is funded by the Korea government ( 2021R1A6A1A03038785 ).

Publisher Copyright:
© 2023 Elsevier B.V.

Keywords

  • Denitrification
  • Groundwater
  • Microbe
  • Nitrate
  • S-nZVI

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