Phosphate removal from aqueous solution using iron oxides: Adsorption, desorption and regeneration characteristics

Zeeshan Ajmal, Atif Muhmood, Muhammad Usman, Simon Kizito, Jiaxin Lu, Renjie Dong, Shubiao Wu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

163 Citations (Scopus)

Abstract

Dynamics of phosphate (PO4 3−) adsorption, desorption and regeneration characteristics of three lab-synthesized iron oxides, ferrihydrite (F), goethite (G), and magnetite (M) were evaluated in this study. Batch experiments were conducted to evaluate the impact of several adsorption parameters including adsorbent dosage, reaction time, temperature, pH, and ionic strength. The results showed that PO4 3− adsorption increased with reaction time and temperature while it decreased with an increase in solution pH. Adsorption isotherm data exhibited good agreement with the Freundlich and Langmuir model with maximum monolayer adsorption capacities of 66.6 mg·g−1 (F), 57.8 mg·g−1 (M), and 50.5 mg·g−1 (G). A thermodynamics evaluation produced ΔG < 0, ΔH > 0, and ΔS > 0, demonstrating that PO4 3− adsorption onto tested minerals is endothermic, spontaneous, and disordered. The PO4 3− removal mostly occurred via electrostatic attraction between the sorbate and sorbent surfaces. Moreover, the PO4 3− sorption was reversible and could be desorbed at varying rates in both neutral and alkaline environments. The good desorption capacity has practical benefits for potential regeneration and re-use of the saturated particles in wastewater treatment systems.

Original languageEnglish
Pages (from-to)145-155
Number of pages11
JournalJournal of Colloid and Interface Science
Volume528
DOIs
Publication statusPublished - Oct 15 2018
Externally publishedYes

Keywords

  • Iron oxides particles
  • Phosphate
  • Regeneration
  • Wastewater treatment

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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