Interaction of divalent metals with struvite: sorption, reversibility, and implications for mineral recovery from wastes

Omanjana Goswami, Ashaki A. Rouff

Research output: Contribution to journalArticlepeer-review


Phosphorus (P) recovered from wastewater as struvite (MgNH4PO4·6H2O) can meet high P demands in the agricultural sector by reuse as a P fertiliser. Heavy metals are prevalent in wastewaters and are common fertiliser contaminants, therefore struvite as a sorbent for metals requires evaluation. Struvite sorption experiments were conducted in model solutions with cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) at 1–5 μM concentrations from pH 7–10. The struvite metal loading increased with dissolved metal concentration and pH, ranging from 2 to 493 mg kg−1. Highest loadings were observed for 5 μM Pb, which exceeded the 120 mg kg−1 European Union (EU) struvite fertiliser limit at all pH values. At 5 μM concentrations, Ni and Cd loadings exceeded EU limits of 100 mg kg−1 at pH 10, and 60 mg kg−1 at pH 8–10, respectively. In desorption experiments, 10–85% metal was released after resuspension in metal-free solutions, with a positive correlation between initial loading and amount desorbed. Distortions of the struvite phosphate band, by Fourier transformation infrared (FTIR) spectroscopy, indicated lowered symmetry of phosphate vibrations with metal sorption. X-ray absorption fine structure spectroscopy (XAFS) analysis of pH 9 solids indicated tetrahedral coordination for Cu and Zn, octahedral coordination for Co and Ni, and Pb in 9-fold coordination. Precipitation of Pb-phosphate minerals was a primary mechanism for Pb sorption. The results provide insight into metal contaminant sorption with struvite in wastewaters, and the potential for metal desorption after recovery.

Original languageAmerican English
JournalEnvironmental Technology (United Kingdom)
StateAccepted/In press - 2022
Externally publishedYes

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology
  • Waste Management and Disposal


  • FTIR
  • Struvite
  • XAFS
  • metals
  • phosphorus


Dive into the research topics of 'Interaction of divalent metals with struvite: sorption, reversibility, and implications for mineral recovery from wastes'. Together they form a unique fingerprint.

Cite this