Adsorptive studies of aqueous zinc ions by foam fractionation.

A foam fractionating column equivalent to a single equilibrium stage, operating in simple mode, has been taken into consideration for the present investigations. The system chosen was zinc and sodium lauryl sulfate. It was experimentally noticed that if the surface excess was measured at random operating conditions the column was producing inconsistent data violating the conditions of simple mode operation. It was therefore of utmost importance to investigate the variables affecting the operation of a foam fractionation column in the simple mode. It was concluded that the height of the foam/liquid interface, the air flow rate and the number of capillaries of the bubbler should be mutually adjusted to bring the column close to the simple mode operation so that the results obtained would be meaningful. At the modified operating conditions, the effect of the metal ion and collector concentration on metal surface excess was investigated. The studies were extended to determine the effect of pH on metal surface excess at various bulk metal concentrations. Finally, the results were compared with those of the previous investigators