ISOTHERM DATA OF FE3-3+, AND CO2+ ADSORBED ON SURFACE OF SILICA-PROPYLPIPERAZINEDITHIOCARBAMATO(, CR)

The silylant agent chloropropyltrimetoxysilane immobilized on silica g el reacts with piperazine, followed by another reaction with carbon di sulfide in the presence of sodium hydroxide, to produce a new matrix s odium propylpiperazinedithiocarbamato silica. The basic centres of the resulting surface complexes are the Cr3+, Fe3+ and Co2+ cations from aqueous solution. The adsorbed isotherms for cations were adjusted to fit Giles models. The isotherm for Cr3+ could be classified as L2, whi le those for Fe3+ and Co2+ fitted the subgroup 2 of C class. The isoth erm data show that the capacity of the final carbamate surface to chem isorb Fe3+ and Co2+ is Only one third that observed for Cr3+. (C) 1998 Elsevier Science B.V.