Aluminum Geochemistry Eh-pH, pe-pH diagrams and Solubility
The Eh-pH diagram for Aluminum in Al-O-OH system is constructed using Al activity as 1E-10. The Aluminum species can dissolve in water in both high and low pH as Aluminum can form complex ions with hydroxide ion (ano with other anions such as SO4). Eh–pH diagram is any of a class of diagrams that designates the fields of stability of mineral or chemical species in terms of the activity of hydrogen ions (pH) and the activity of electrons (Eh). All of the reactions illustrated on Eh–pH diagrams involve either proton transfer (e.g., hydrolysis) or electron transfer (oxidation or reduction) or both.