Abstract
| - The colloidal behavior of nickel aqueous suspensions is studied and compared to that of NiO suspensions.Under acidic conditions, nickel readily dissolves, but no dissolution takes place at basic pH. ζ potential isstudied as a function of pH, showing that the isoelectric point (IEP) occurs at pH 3.5−4. Above the IEP thereis a ζ potential plateau, which is associated to the predominance of NiO(OH) species. At pH 9 a new decreasein ζ potential is associated to NiO predominance. XPS studies support that suspensions prepared at pH >9lead to NiO-enriched species, while suspensions prepared at lower pH form NiO(OH) species.
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