IMMOBILIZED DITHIOCARBAMATE GROUPS ON SILICA - CHEMISORPTION OF SOME CATIONS FROM ETHANOLIC SOLUTION

Immobilized dithiocarbamate was prepared by reacting a 3-propylethylen ediamine group, covalently bonded to silica gel, with carbon disulfide in toluene. This modified surface has 6.7 x 10(-4) mol g(-1) of ligan d sites available to extract cobalt, nickel, copper and zinc from etha nol solution. The adsorption isotherms are very similar in shape for a ll cations and conform to the Langmuir model. However, the degree of a dsorption indicated a metal: a ligand ratio of 1:3 for cobalt, 1:2 for nickel and 1:1 for copper and zinc complexes. These cations are sulfu r-bonded to the anchored ligand. The isotherm of the cobalt chemisorpt ion data agrees with oxidation of cobalt to the trivalent state. The g eometries of these complexes are similar to those obtained in solution . The results suggest a very similar behavior of the dithiocarbamate c hemically bonded on silica gel with that of these ligands in the unbon ded state.