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School of Earth & Space Exploration. Chemical and mineralogical comparison of two antibacterial clays . Amanda Turner Dr. Lynda Williams, Dr. Shelley Haydel*, Christine Remenih* & Tanya Borchardt*. ANTIBACTERIAL EFFECTIVENESS. Isolating bacteria affected by clay.
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School of Earth & Space Exploration Chemical and mineralogical comparison of two antibacterial clays Amanda Turner Dr. Lynda Williams, Dr. Shelley Haydel*, Christine Remenih* & Tanya Borchardt*
ANTIBACTERIAL EFFECTIVENESS Isolating bacteria affected by clay Isolating the antibacterial clay minerals ANTIBACTERIAL MECHANISM Testing for physical interaction Testing for chemical interaction ICP-MS, Electron Probe, pH, Eh: Toxin provided? Nutrient depleted? SEM, Mineralogy: Clay-cell attraction? Physical disruption? Investigating Antibacterial Clay Minerals
Bulk Mineralogy NONClaysClays 10.4% Qtz 44.9% Smectite 6.2% Olig 16.5% Illite 5.3% Alb 1.1% Gibbsite 6.7% Others NONClaysClays 39.3% Qtz 21.5% Illite 3.2% Pyrite 16.2% Smectite 1.2% Barite 4.1% Kaol. 1.0% Magnetite 3.3% Pyroph.
Clay Mineralogy No ONE antibacterial mineral How about the chemistry?
Adsorbed onto surface X Interlayer Surfaces X X X
Antibacterial clay Antibacterial clay graphite 10-20 nm amorphous particles 20 nm thick clay laths NV OR
x X X X X X x H2O x x x Leachate Chemistry Antibacterial Clay 200C OR07 Kills NV07 Kills C H O N S P F Cl Br I Hg
x X X X X X x H2O x x x OH x x x Leachate Chemistry Antibacterial Clay 200C 550C OR07 Kills NV07 Kills OR07 doesn’t kill NV0 partially kills C H O N S P F Cl Br I Hg Rb Cs Se Cd As
x X X X X X x H2O x x x OH x x x Leachate Chemistry Antibacterial Clay 200C 550C 900C OR Kills NV Kills OR doesn’t kill NV partially kills Neither Kill! Elements not volatilized Fe Zn Ni Cu V Co W Cr Ag Cd Pb U All below MIC In oxidized form! C H O N S P F Cl Br I Hg Rb Cs Se Cd As
pHEh (mV) NV (<2.0µm) 3.96 +146 OR (<2.0µm) 3.48 +172 French clays HIGH LOW Non-AB clays Neutral Neutral
Healthy E. coli 500 nm 5 µm 2 µm 500 nm 2 µm After clay incubation
x X X X X X x What We’ve Learned Antibacterial Clay PHYSICAL CHEMICAL Mineralogy Leachates No ONE mineral responsible SEM Heating regimes may volatilize vital elements pH, Eh No visible disruption of the cell Extreme pH, Eh values Illite/Smectite Agents soluble at pH ~4
Future Work • More Imaging! • Model elemental speciation at varying pH and Eh – similarities? • Cation exchange (xc) - remove xc’able ions -test xc solution and xc’d clay • Electron and Ion Microscopy - clay/bacteria interactions
NCCAM Acknowledgements Other Colleagues Dr. Dennis Eberl Dr. Ross Giese • Dr. Shelley Haydel • Tanya Borchardt • Christine Remeni • Amanda Cotey • Dr. Renu Sharma • Dr. Karl Weiss • Dr. Laurence GarvieDr. Gordon Moore • Zack Bowles • Dr. Panjai Prapaipong LeRoy Eyring CSSS