Environmental Chemistry

Adsorption and desorption of bivalent metals to hematite nanoparticles†

  1. Valerie A. Grover,
  2. Jinxuan Hu,
  3. Karen E. Engates,
  4. Heather J. Shipley*

Article first published online: 9 DEC 2011

DOI: 10.1002/etc.712

Issue

Environmental Toxicology and Chemistry

Environmental Toxicology and Chemistry

Special Issue: Nanomaterials in the Environment

Volume 31, Issue 1, pages 86–92, January 2012

Additional Information

How to Cite

Grover, V. A., Hu, J., Engates, K. E. and Shipley, H. J. (2012), Adsorption and desorption of bivalent metals to hematite nanoparticles. Environmental Toxicology and Chemistry, 31: 86–92. doi: 10.1002/etc.712

Author Information

  1. Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX, USA

*Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX, USA.

  1. †

    Presented at Nano 2010: International Conference on the Environmental Effects of Nanomaterials, Clemson University, August, 2010.

Publication History

  1. Issue published online: 9 DEC 2011
  2. Article first published online: 9 DEC 2011
  3. Accepted manuscript online: 12 OCT 2011 10:07PM EST
  4. Manuscript Accepted: 21 DEC 2010
  5. Manuscript Revised: 1 DEC 2010
  6. Manuscript Received: 29 SEP 2010

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Keywords:

  • Hematite;
  • Nanoparticles;
  • Metal adsorption;
  • Desorption

Abstract

The use of commercially prepared hematite nanoparticles (37.0 nm) was studied as an adsorbent in the removal of Cd(II), Cu(II), Pb(II), and Zn(II) from aqueous solutions. Single-metal adsorption was studied as a function of metal and adsorbent concentrations, whereas binary metal competition was found to be dependent on the molar ratio between the competing metals. Competitive effects indicated that Pb had strong homogenous affinity to the nanohematite surface, and decreased adsorption of Cd, Cu, and Zn occurred when Pb was present in a binary system. Metal adsorption strength to nanohematite at pH 6.0 increased with metal electronegativity: Pb > Cu > Zn ∼ Cd. Equilibrium modeling revealed that the Langmuir–Freundlich composite isotherm adequately described the adsorption and competitive effects of metals to nanohematite, whereas desorption was best described by the Langmuir isotherm. The desorption of metals from nanohematite was found to be pH dependent, with pH 4.0 > pH 6.0 > pH 8.0, and results showed that greater than 65% desorption was achieved at pH 4.0 within three 24-h cycles for all metals. Environ. Toxicol. Chem. 2012;31:86–92. © 2011 SETAC

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