Open AccessXAFS determination of the bacterial cell wall functional groups responsible for complexation of Cd and U as a function of pH
Author(s) -
Kelly S. D.,
Boyanov M.I.,
Bunker B. A.,
Fein J. B.,
Fowle D. A.,
Yee N.,
Kemner K. M.
Publication year - 2001
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049500021014
Subject(s) - x ray absorption fine structure , adsorption , chemistry , bacillus subtilis , metal , sorption , biophysics , bacteria , inorganic chemistry , organic chemistry , spectroscopy , physics , quantum mechanics , biology , genetics
Bacteria, which are ubiquitous in near‐surface geologic systems, can affect the distribution and fate of metals in these systems through adsorption reactions between the metals and bacterial cell walls. Recently, Fein et al. (1997) developed a chemical equilibrium approach to quantify metal adsorption onto cell walls, treating the sorption as a surface complexation phenomenon. However, such models are based on circumstantial bulk adsorption evidence only, and the nature and mechanism of metal binding to cell walls for each metal system have not been determined spectroscopically. The results of XAFS measurements at the Cd K‐edge and U L3‐edge on Bacillus~subtilis exposed to these elements show that, at low pH, U binds to phosphoryl groups while Cd binds to carboxyl functional groups.