Binding characteristics of copper and cadmium by cyanobacterium Spirulina platensis

TY - JOUR

T1 - Binding characteristics of copper and cadmium by cyanobacterium Spirulina platensis

AU - Fang, Linchuan

AU - Zhou, Chen

AU - Cai, Peng

AU - Chen, Wenli

AU - Rong, Xingmin

AU - Dai, Ke

AU - Liang, Wei

AU - Gu, Ji Dong

AU - Huang, Qiaoyun

N1 - Funding Information: This work was financially supported by the National Natural Science of Foundation of China ( 40825002 ) and Huazhong Agricultural University Scientific & Technological Self-innovation Foundation ( 2009YB005 ). We gratefully acknowledge Dr. Bo He and Dr. Zhi Xie (NSRL, USTC, China) for their helpful technical assistance of XAFS experiments. We also thank Dr. Torbjörn Karlsson from Swedish University of Agricultural Sciences for XAFS data processing.

PY - 2011/6/15

Y1 - 2011/6/15

N2 - 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.

AB - 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.

KW - Cd(II)

KW - Chemical modifications

KW - Cu(II)

KW - Sequestration mechanisms

KW - Spirulina platensis

KW - XAFS

UR - http://www.scopus.com/inward/record.url?scp=79956159761&partnerID=8YFLogxK

U2 - 10.1016/j.jhazmat.2011.03.122

DO - 10.1016/j.jhazmat.2011.03.122

M3 - 文章

C2 - 21514723

AN - SCOPUS:79956159761

SN - 0304-3894

VL - 190

SP - 810

EP - 815

JO - Journal of Hazardous Materials

JF - Journal of Hazardous Materials

IS - 1-3

ER -