Iron-crosslinked alginate derived Fe/C composites for atrazine removal from water

Cheng Lei, Yan Song, Fanxu Meng, Yuqing Sun, Daniel C.W. Tsang, Kun Yang, Daohui Lin

Research output: Journal article publicationJournal articleAcademic researchpeer-review

1 Citation (Scopus)

Abstract

Fe/C composite is emerging as a promising nanoscale zero-valent iron (nZVI) based material for wastewater treatment to counteract the limitations of nZVI, while its preparation method, structure-activity relationship, and working mechanisms and conditions still need to be studied. In this study, Fe/C composites derived from iron-crosslinked alginate was successfully achieved via high temperature pyrolysis. Ferric ions were only transformed into Fe3O4/γ-Fe2O3 at low pyrolysis temperature (≤500 °C), whereas Fe0/Fe3C became the primary Fe species with the formation of graphitic carbon at elevated pyrolysis temperature (≥700 °C). Fe/C composites from higher pyrolysis temperature presented better performance in atrazine (ATZ) removal, and the optimal pyrolysis temperature was 800 °C (Fe/C-800). Batch experiments showed that the removal kinetics of ATZ (10 mg L−1) by Fe/C-800 (0.2 g L−1) followed pseudo-second-order model, and 24-h ATZ removal efficiency maintained at 93.5 ± 1.0% within pH 3–9. The adsorption by the graphitic carbon phase of Fe/C-800 was the principal contributor to the pH-independent superior performance in ATZ removal, and the Langmuir model fitted adsorption capacity was 64.8 mg g−1 at pH 6. Although the carbon-phase adsorbed ATZ was basically unavailable for degradation, Fe0/Fe3C-mediated ATZ degradation contributed to the great reactivity of Fe/C-800 at pH 3. Fe0/Fe3C in Fe/C-800 was more efficient for ATZ degradation than commercial nZVI, and oxidative dealkylation by Fe0/Fe3C mediated Fenton reaction was the predominant ATZ degradation pathway rather than reductive dechlorination. Moreover, the produced ATZ degradation intermediates could be further adsorbed by Fe/C-800, mitigating potential secondary pollution. Thus, iron-crosslinked alginate derived Fe/C composites can be an excellent alternative for nZVI in organics-polluted water treatment with great reactivity and wide pH applicability.

Original languageEnglish
Article number143866
JournalScience of the Total Environment
Volume756
DOIs
Publication statusPublished - 20 Feb 2021

Keywords

  • Adsorption
  • Crosslinked alginate
  • Fe/C composite
  • nZVI
  • Oxidative dealkylation

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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