Electron paramagnetic resonance (EPR) study of Cu2+ and Mn2+ ions interacting as probes with calcium carbonate during the transformation of vaterite into cubic calcite

Abstract

The interactions between trace elements and carbonates (CaCO₃) in deionized water have been evaluated. The behaviour of Cu and Mn was investigated using spectrometric techniques, namely electron paramagnetic resonance, plasma atomic emission and high resolution electron microscopy. The results obtained show that, for low concentrations (10^–4 mol dm^–3), these metals do not form a precipitated phase on vaterite and cubic calcite, but they interact favourably with the CaCO₃ structure leading to the transformation of vaterite into cubic calcite. Our investigations have resolved that these two metals can be used successfully as probes to follow and control this crystalline transformation and to assess its extent with time.