A study of the species involved in the extraction of metal
ions from aqueous solutions into organic solvents with long-chain
carboxylic acids has been made.
The theoretical analysis of the extraction data in terms of a
single equilibrium approach and a multiple equilibria method has been
made. The two approaches have been shown to be equivalent in the
case of one extracted complex, and an extraction expression has been
proposed to describe the extractions. The analysis of the data has
been considered in terms of this expression by graphical and
Under the equilibrium extraction conditions studied, the
extracted species in the case of copper (II), cobalt (II) and nickel
(II) systems appear to be predominantly dimeric in nature and are
usually solvated with carboxylic acid molecules in the organic phase.
Results obtained from the extraction of copper from an
aqueous solution into free-falling drops of n-octoic acid dissolved
in carbon tetrachloride indicate that the rate of extraction does
not vary appreciably over the pH range studied. The measurement
of the interfacial tensions in the same system suggests that no
abrupt change in the nature of the interfacial region occurs as the
pH of extraction increases.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.
Great Britain, Ministry of Technology, Warren Spring Laboratory.