Influence of selected natural complexants on the mobilization and purging of copper from aqueous media into supercritical carbon dioxide

摘要: The mobilization/purging of copper(II) or zinc(II) from aqueous solution by in situ complexometric extraction into supercritical carbon dioxide (SC-CO2) is described. On line detection using AAS has permitted the kinetics process to be monitored over course extraction. A single step procedure at moderate pressure and 50 °C resulted virtually quantitative removal 0.08–2.4 µmol ml–1 Cu with an estimated half-life (t1/2) 3–5 min. By contrast, a small portion zinc media was mobilized appreciably slower rate which apparently result non-equilibrium carbonate precipitation. Recoveries CuII Cu–fulvic acid (FA) solutions Cu–FA–sand suspensions were dependent on concentrations both FA sample. Whereas pseudo-first-order provided adequate model for (mean t1/2= 17.8 min) containing 1.2 CuII+ 1.05 FA, higher loading caused apparent coagulation accompanied release bound (t1/2= 2.5 but immobilization remainder. For lower Cu–FA (0.48 0.10 per millilitre), no evident analyte purged 16.7 quantitatively. extractions mixtures, recoveries less than changes response curve time better approximated sum two Gaussian curves exponential decay curves. recovered quantitatively 1%(m/m) oxalic decreased purging this complexant increased recovery only moderately.