50 research outputs found
Atomic‐Scale Manipulation and In Situ Characterization with Scanning Tunneling Microscopy
No “Slippery Slope”? An Empirical Case Study on the Effect of Secular Science Textbooks on Student Religiosity in a Christian Private School
Deeper than rhizomes, becoming decalcomaniacal: a reflexive response to Murakami and Siegel’s “Becoming Bermuda grass”
Surface Complexation of Neptunium(V) onto Whole Cells and Cell Components of Shewanella alga
Discrete site surface complexation constants for lanthanide adsorption to bacteria as determined by experiments and linear free energy relationships
Bacteria are abundant in many natural and engineered environments where they are thought to exert important controls on the cycling, mobility, bioavailability, and toxicity of metal contaminants. In order to probe their role in moderating the behavior of lanthanides, pH-dependent adsorption edges of 13 individual lanthanides and yttrium to the Gram-negative bacterium Pantoea agglomerans were used to generate discrete site surface complexation constants. The calculated surface complexation constants were compared with stability constants estimated using linear free energy relationships based on a number of hydroxyl-containing ligands. The experimental data suggests that lanthanide adsorption edges below pH 6.5 are consistent with adsorption to phosphate groups for the light and some of the middle lanthanides (La to Gd), whereas some of the middle and heavy lanthanides appear to favor carboxyl co-ordination (Tb to Yb), although exceptions occur in each grouping. The experimentally derived surface complexation constants for carboxyl coordination were of similar magnitude to stability constants estimated from linear free energy correlations using fulvic acid stability constants. The implication is that the adsorption of lanthanides to bacterial surfaces could be modeled reasonably well using lanthanide stability constants for natural organic matter, except perhaps at low pH where phosphate binding dominates