• A study of the nickel-humic acid bond and aqueous nickel speciation using FT-IR spectrometry and the geochemical computer program MINTEQA2

      Bassett, R. L.; Babel, Carol Ann; Bassett, R. L.; Hiskey, J. Brent (The University of Arizona., 1994)
      FT-IR analysis of nickel-humic acid bond formation in an aqueous solution was evaluated using the HA TR and CIRCLE internal reflectance sampling accessories. Nickel complexation to humic acid carboxyl groups was detected in solutions containing Nt2 concentrations greater than 6 mM. CIRCLE spectra showed better sample representation, whereas HA TR spectra showed better spectrum resolution. Various hypothetical aqueous nickel scenarios were modeled using the geochemical equilibrium computer program MINTEQA2. The distribution of nickel species at maximum nickel concentrations were shown to be influenced by ions present, by variations in pH, and by variations in nickel, humic acid, and ammonium concentrations. Consistent 1.0 molal concentrations for all scenario ions were used to demonstrate the influence of each ion or ion combination on nickel speciation. Nickel speciation under environmental aquifer ion concentrations, were predicted using chemical analyses from wells in the Globe-Miami, Arizona mining district and the French Prairie Area in Oregon.