Potentiometric study of binary complexes of methyl 2-pyridyl ketone oxime, phenyl 2-pyridyl ketone oxime and diacetyl monooxime with some transition and heavy metal ions in aqueous solution.

The complexation reaction between some oximes including methyl-2-pyridylketone oxime (MPKO), phenyl-2-pyridylketone oxime (PPKO) and diacetyl monooxime (DMO) with some transition and heavy metal ions Co2+, Ni2+, Zn2+, Pb2+, Fe2+, Fe3+, Cr3+ and La3+ has been studied potentiometrically in aqueous solution at 25+/-0.1 degrees C and ionic strength (mu) of 0.1M supported by KCl. The overall stability constants logbeta's of respective species were obtained by computer refinement of pH-volume data using BEST program. The best model among the several proposed models was selected according to the lowest sigma(fit) value. The main species in binary systems are ML, ML2, MLH, MLH2, ML2H, ML2H2, MOHL, M(OH)2L, M(OH)L2 and M(OH)2L2 (L = MPKO or PPKO or DMO).