Mechanisms of phosphate removal by Micron-Scale Zero-Valent iron

Ying Zhao, Qingxu Li, Qiantao Shi, Beidou Xi, Xinyi Zhang, Zhiqiang Jian, Gaoting Zhou, Xiaoguang Meng, Xuhui Mao, Dejun Kang, Bin Gong

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Extensive studies have been carried out on phosphate removal by zero valent iron (ZVI). Different mechanisms of phosphate removal by ZVI such as phosphate adsorption and precipitation of ferric phosphate and vivianite (Fe3(PO4)2·8H2O) have been reported. In this study, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray powder diffraction (XRD), and X-ray absorption near edge spectroscopy (XANES) were used to elucidate the mechanisms of phosphate removal by micron-scale zero-valent (mZVI). Time-series ATR-FTIR analysis revealed that phosphate was removed by ZVI in two steps: a) adsorption of phosphate in the first 3 days, and b) slow conversion of the adsorbed phosphate into the precipitated form in 6 days. XRD and XANES analysis determined that iron oxides, ferric ion, and ZVI with oxide layer inhibited the formation of vivianite, resulting in the formation of phosphate precipitates, such as H2Fe(II)P2O7. The results suggested that phosphate is removed by ZVI mainly through precipitation under aerobic conditions. The knowledge gained in this study improves the fundamental understanding of the phosphate removal processes via ZVI.

Original languageEnglish
Article number123706
JournalSeparation and Purification Technology
Volume319
DOIs
StatePublished - 15 Aug 2023

Keywords

  • Adsorption
  • Phosphate
  • Precipitation
  • Vivianite
  • Zero valent iron

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