Modeling the sorption kinetics of divalent metal ions to hematite

Byong Hun Jeon, Brian A. Dempsey, William D. Burgos, Richard A. Royer, Eric E. Roden

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

The sorption kinetics of the divalent metals Zn, Co, Ni, and Cd to hematite were studied in single sorbate systems with high sorbate/sorbent ratios (from 1.67 to 3.33mol sorbate/mol sorption sites) in 10mM Na-piperazine N,N′-bis 2-ethane sulfonic acid (Na-PIPES) solution at pH 6.8. The experimental data showed a rapid initial sorption (half-time about 1min) followed by slower sorption that continued for 1-5 days. The sequence of fast to slow sorption kinetics was modeled by slow inner-sphere (IS) complexation in equilibrium with outer-sphere (OS) complexes. Although the OS reaction was fast and considered to be in equilibrium, the extent of OS complexation changed over time due to increased surface potential from the IS complexes. For example, the model showed that the dimensionless OS complexation function, Kos, decreased from 0.014 initially to 0.0016 at steady state due to sorption of 4×10 -5M Zn(II) to 2gL-1 hematite. Sorption rate constants, kads, for the various divalent metals ranged from 6.1 to 82.5M -1s-1. Desorption rate constants, kdes, ranged from 5.2×10-7 to 6.7×10-5s-1. This study suggests that the conversion from OS to IS complex was the rate-determining step for the sorption of divalent metals on crystalline adsorbents.

Original languageEnglish (US)
Pages (from-to)2499-2504
Number of pages6
JournalWater Research
Volume38
Issue number10
DOIs
StatePublished - May 1 2004

Fingerprint

Hematite
hematite
Metal ions
Sorption
sorption
kinetics
Kinetics
ion
metal
modeling
Complexation
complexation
Rate constants
Metals
ethane
Surface potential
Ethane
Sorbents
Adsorbents
Desorption

All Science Journal Classification (ASJC) codes

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

Cite this

Jeon, Byong Hun ; Dempsey, Brian A. ; Burgos, William D. ; Royer, Richard A. ; Roden, Eric E. / Modeling the sorption kinetics of divalent metal ions to hematite. In: Water Research. 2004 ; Vol. 38, No. 10. pp. 2499-2504.
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Modeling the sorption kinetics of divalent metal ions to hematite. / Jeon, Byong Hun; Dempsey, Brian A.; Burgos, William D.; Royer, Richard A.; Roden, Eric E.

In: Water Research, Vol. 38, No. 10, 01.05.2004, p. 2499-2504.

Research output: Contribution to journalArticle

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