|
|
Type of Document Master's Thesis Author Hepinstall, Sarah Elizabeth Author's Email Address shepinst@nd.edu URN etd-04132004-142711 Title Comparison of the Effects of Hydroxamate Siderophores on Lead and Cadmium Adsorption to Kaolinite Degree Master of Science Department Civil Engineering and Geological Sciences Advisory Committee
Advisor Name Title Patricia Maurice Committee Chair Jeremy Fein Committee Member Peter Burns Committee Member Keywords
- kaolinite
- cadmium
- siderophores
- adsorption
- lead
Date of Defense 2004-03-25 Availability restricted Abstract Siderophores are Fe(III)-specific organic ligands biosynthesized by microbes in Fe-deficient environments. They also complex other metals, such as Pb and Cd, influencing metal mobility. This study compared the effects of siderophores desferrioxamine-B (DFO-B), desferrioxamine-D (DFO-D1), desferrioxamine-E (DFO-E), as well as siderophore-like ligand acetohydroxamic acid (aHA) on Pb and Cd (except for DFO-E) adsorption to kaolinite (KGa-1b) at pH 4.5 to 9, in 0.1 M NaClO4, at 22oC, in the dark. At pH > 6, all of the ligands inhibited Pb adsorption with inhibition increasing in the order aHA < DFO-D1 < DFO-B < DFO-E. At lower pH, the presence of DFO-B slightly enhanced Pb adsorption. These ligands also inhibited Cd adsorption at pH > 8, but had no effect at low pH. Modeling the systems with PHREEQC suggested that the siderophores in solution out-competed the kaolinite surface for the metal cations, thus causing decreased adsorption at high pH.Files
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access HepinstallSE052004.pdf 248.50 Kb 00:01:09 00:00:35 00:00:31 00:00:15 00:00:01 indicates that a file or directory is accessible from the campus network only.