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Analysis of Total Aluminum and Dissolved Aluminum. Louis McDonald and Jeff Skousen Plant & Soil Sciences West Virginia University. Aluminum. The Good. The Bad. The Ugly. ?. Where is the Aluminum?. Aluminum – “Free” Ion. Al 3+. Aluminum Complexes. Complexes. Al 3+. Inorganic.
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Analysis of Total Aluminum and Dissolved Aluminum Louis McDonald and Jeff Skousen Plant & Soil Sciences West Virginia University
Aluminum The Good The Bad The Ugly ?
Aluminum Complexes Complexes Al3+ Inorganic Organic e.g. fluoride, hydroxide, sulfate, carbonate O Al3+
Aluminum Complexes Complexes Al3+ Inorganic Organic hydroxide Small e.g. acetic, citric
Aluminum Complexes Complexes Al3+ Inorganic Organic hydroxide Small Large e.g. acetic, citric e.g. humic acid, fulvic acid
Where is the Aluminum? Al3+ Complexes Inorganic Organic Large Small OH-
Aluminum Particles By Composition Aluminum hydroxides and oxides Gibbsite (Al(OH)3) Kaolinite Al2Si2O5(OH)4 Aluminosilicates Feldspar (KAlSi3O8) Phyllosilicates Kaolinite (Si2Al5(OH)4)
Aluminum Particles By Size V. Small Small Medium Large Very fine clays Clays Silts Sands Colloids – Al on surface does matter
Colloids Ca2+, Mg2+, K+, etc. Al3+
Very Large Very Small Particles Complexes Al3+ V. Small Inorganic Organic Small OH- Medium Large Small Large
Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small OH- Medium Large Small Large Definitely Dissolved Definitely Solid
Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic OH- Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
The Curious Case of Hydroxide Al3+ Total Dissolved Al Al(OH)4-
Al3 Al1 Al13 From Casey et al. 2010
Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic OH- Small Medium Large Small Large Definitely Dissolved Definitely Solid Polynuclear Al Filter Size Operationally Dissolved
Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
Why filter? PROPERLY! Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
What do instruments measure? Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
Acidifying Samples + Acid, H+ Al3+ H – Complexes Al in Solids H on Surfaces Al3+ Al – Complexes Al in Solids Al on Surfaces Dissolved Al Dissolved Al
Why might hardness matter? Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
What is toxic? Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
What is toxic? Very Large Very Small Ingestion or Inhalation Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
What is toxic? Very Large Very Small Particles Al3+ Complexes Plants, algae V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
What is toxic? Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Fish acute Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
What is toxic? Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Fish chronic? Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
What is Total Al? What is dissolved Al? Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved
Questions? Very Large Very Small Particles Al3+ Complexes V. Small Inorganic Organic Small Medium Large Small Large Definitely Dissolved Definitely Solid Filter Size Operationally Dissolved