Uptake of metal ions by a silica-based tetraphenylporphyrin sorbent

The [5-p-carboxyphenyl)-10,15,20-triphenyl]porphyrin (TPP) covalently attac hed to aminopropyl silica gel was examined with respect to the sorption of transition metal ions. The distribution coefficients (K-d) are reported for some metal ions with this new sorbent as a function of pH. It was found th at in optimum pH conditions the sorption of Cu(II) and Fe(III) is much fast er than that of Co(II) and Cr(III). The binding of metal ions is strongly a ffected by the presence of various species accelerating the complex formati on. The application of porphyrin ligands for preconcentration and metal-mat rix separation was also examined using complex formation in solution couple d with an anion exchange resin and column chelation procedure, e.g. sorptio n of metal on an anion exchanger previously loaded with tetra(4-carboxyphen yl)porphyrin.