Binding characteristics of copper and cadmium by cyanobacterium Spirulina platensis

Linchuan Fang, Chen Zhou, Peng Cai, Wenli Chen, Xingmin Rong, Ke Dai, Wei Liang, Ji Dong Gu, Qiaoyun Huang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

Cyanobacteria are promising biosorbent for heavy metals in bioremediation. Although sequestration of metals by cyanobacteria is known, the actual mechanisms and ligands involved are not very well understood. The binding characteristics of Cu(II) and Cd(II) by the cyanobacterium Spirulina platensis were investigated using a combination of chemical modifications, batch adsorption experiments, Fourier transform infrared (FTIR) spectroscopy and X-ray absorption fine structure (XAFS) spectroscopy. A significant increase in Cu(II) and Cd(II) binding was observed in the range of pH 3.5-5.0. Dramatical decrease in adsorption of Cu(II) and Cd(II) was observed after methanol esterification of the nonliving cells demonstrating that carboxyl functional groups play an important role in the binding of metals by S. platensis. The desorption rate of Cu(II) and Cd(II) from S. platensis surface was 72.7-80.7% and 53.7-58.0% by EDTA and NH4NO3, respectively, indicating that ion exchange and complexation are the dominating mechanisms for Cu(II) and Cd(II) adsorption. XAFS analysis provided further evidence on the inner-sphere complexation of Cu by carboxyl ligands and showed that Cu is complexed by two 5-membered chelate rings on S. platensis surface.

Original languageEnglish
Pages (from-to)810-815
Number of pages6
JournalJournal of Hazardous Materials
Volume190
Issue number1-3
DOIs
StatePublished - 15 Jun 2011
Externally publishedYes

Keywords

  • Cd(II)
  • Chemical modifications
  • Cu(II)
  • Sequestration mechanisms
  • Spirulina platensis
  • XAFS

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