Lead immobilization by phosphate in the presence of iron oxides: Adsorption versus precipitation

Qiantao Shi, Shujuan Zhang, Jie Ge, Jinshan Wei, Christos Christodoulatos, George P. Korfiatis, Xiaoguang Meng

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

As a commonly used corrosion inhibitor, phosphate (PO4) has a complicated effect on the fate and transport of lead (Pb) in drinking water systems. While the formation of pyromorphite has been recognized to be the major driving force of the Pb immobilization mechanism, the role of adsorption on iron oxides is still not clear. This study aims to clarify the contributions of adsorption and precipitation to Pb removal in a system containing both iron oxides and PO4. A combination of batch experiments, X-ray absorption spectroscopy, infrared spectroscopy, and electron spectroscopy was employed to distinguish the adsorbed and precipitated Pb species. The results indicated that the adsorption of Pb on iron oxides still occurred even when the solution was supersaturated to pyromorphite (i.e., 5 mg/L P with 0.1–30 mg/L Pb in 0.01 M NaCl solution at neutral pH). In the tap water containing 0.92 mg/L P and 1 mg/L Pb, adsorption on iron oxides contributed more (62–67%) than precipitation (33–38%) in terms of Pb removal. Surprisingly, the pre-formed pyromorphite is transformed to adsorbed species after mixing with iron oxides in water for 24 h. The illustration of this transformation is important to understand the immobilization mechanisms and transport behaviors of Pb in drinking water systems after the utilization of PO4.

Original languageEnglish
Article number115853
JournalWater Research
Volume179
DOIs
StatePublished - 15 Jul 2020

Keywords

  • Adsorption
  • Iron oxides
  • Lead
  • Phosphate
  • Precipitation

Fingerprint

Dive into the research topics of 'Lead immobilization by phosphate in the presence of iron oxides: Adsorption versus precipitation'. Together they form a unique fingerprint.

Cite this