The mineral northupite Na3Mg(CO3)2Cl was synthesized from a solar Adriatic seawater brine pond to which Na2CO3 was added at 373°K. The precipitated northupite had a surface area (P) of 6.0 ± 0.4 m2g-1, and the thermodynamic solubility product was estimated to be log K Na3Mg(CO3)2Cl = -4.8 ± 0.3 at 25°C. This value was used to calculate the interfacial energy (σ = 50 erg cm-2) for the homogeneous nucleation of northupite. The solubility constant determined in this study has been used to examine the saturation state of Mahega Lake and Lake Katwe (Uganda). The waters from Lake Katwe were found to be supersaturated with respect to northupite. The adsorption of Cu and Cd onto northupite particles was studied in seawater. Both metals are strongly adsorbed. Adsorption constants and the specific area of northupite occupied by Cd and Cu using Langmuir adsorption isotherms and equilibrium constants for surface complex formation have been determined.
ASJC Scopus subject areas
- Geochemistry and Petrology