KINETICS OF HEAVY-METAL REACTIONS WITH FERROUS SULFIDE

The kinetics of heavy metal exchange with ferrous sulfide is examined. The removal rates are dependent on the type and concentration of meta ls, as well as pH. At pH 7, the removal rates follow the order: Cu(II) > Zn(II) > Pb(II) > Cd(II). The reaction with copper occurs very rapi dly; however it is inhibited by copper complexation with EDTA. The rat e of both lead and cadmium exchange decreases at low pH. Competition a mong metals for active FeS sites may exist. The addition of copper and subsequent formation of CuS seem to assist in the removal of other me tals, apparently due to adsorption onto the CuS.