Sulfidation of lead-loaded zeolite microparticles and flotation by amylxanthate.

The possibility of recovering lead-loaded zeolite Y microparticles (PbY) by flotation after sulfidation was investigated using amyl xanthate (AMX) as the collector. The sulfidation process (by aqueous Na2S) was first studied as a function of the medium composition (Na2S concentration, pH), and the solid phases were characterized by various physicochemical techniques (X-ray photoelectron spectroscopy, high-frequency impedance measurements, and electrochemistry). Progressively increasing the sulfidation level resulted in the concomitant transformation of Pb(II) species ion-exchanged in the zeolite into PbS clusters that were mostly located at the external boundaries of the zeolite particles while remaining attached to the aluminosilicate (PbS-Y).

Immobilization of iodide on copper(I) sulfide minerals.

In the goal of finding efficient scavengers for radioiodide in conditions (pH, pE) close to those encountered in deep geological sites, sorption of iodide ions on cuprous sulfide minerals (especially roxbyite, Cu(1.75)S) has been studied. Surface analysis by X-ray photoelectron spectroscopy has shown that commercial cuprous sulfides are covered by an oxidized overlayer (mainly in the form of CuSO(4)).

A comparative study of the removal of trivalent chromium from aqueous solutions by bentonite and expanded perlite.

Local bentonite and expanded perlite (Morocco) have been characterised and used for the removal of trivalent chromium from aqueous solutions. The kinetic study had showed that the uptake of Cr(III) by bentonite is very rapid compared to expanded perlite. To calculate the sorption capacities of the two sorbents, at different pH, the experimental data points have been fitted to the Freundlich and Langmuir models, respectively, for bentonite and expanded perlite.