Enhanced arsenite removal by superparamagnetic iron oxide nanoparticles in-situ synthesized on a commercial cube-shape sponge: adsorption-oxidation mechanism

Xiang Yang Lou, Roberto Boada*, Laura Simonelli, Manuel Valiente

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)

Abstract

Hypothesis: The easy aggregation of superparamagnetic iron oxide nanoparticles (SPION) greatly reduces their adsorption performance for removing arsenic (As) from polluted water. We propose to exploit the porosity and good diffusion properties of a cube-shaped cellulose sponge for loading SPION to reduce the aggregation and to develop a composite adsorbent in the cm-scale that could be used for industrial applications. Experiments: SPION were in-situ synthesized by co-precipitation using a commercial cube-shaped sponge (MetalZorb®) as support. The morphology, iron-oxide phase, adsorption performance and thermodynamic parameters of the composite adsorbent were determined to better understand the adsorption process. X-ray absorption spectroscopy (XAS) was used to investigate the chemical state of the adsorbed As(III). Findings: The adsorption of the supported SPION outperforms the unsupported SPION (ca. 14 times higher adsorption capacity). The modelling of the adsorption isotherms and the kinetic curves indicated that chemisorption is controlling the adsorption process. The thermodynamic analysis shows that the adsorption retains the spontaneous and endothermic character of the unsupported SPION. The XAS results revealed an adsorption-oxidation mechanism in which the adsorbed As(III) was partially oxidized to less toxic As(V) by the hydroxyl free radical (•OH) generated from Fe(III) species and by the hydroxyl groups.

Original languageEnglish
Pages (from-to)460-467
Number of pages8
JournalJournal of Colloid and Interface Science
Volume614
DOIs
Publication statusPublished - 15 May 2022

Keywords

  • Adsorption-oxidation
  • Arsenite removal
  • Commercial cube sponge
  • superparamagnetic iron oxide nanoparticles (SPION)
  • X-ray absorption spectroscopy
  • Water Purification/methods
  • Adsorption
  • Arsenic/chemistry
  • Kinetics
  • Arsenites/chemistry
  • Magnetic Iron Oxide Nanoparticles
  • Water Pollutants, Chemical/chemistry
  • Ferric Compounds/chemistry
  • Hydrogen-Ion Concentration

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