Objective: The lowest concentration of sodiumdodecyl sulfate (SDS) separated capably fromits feed solution
using a one-stage foam separation was determined. Both enrichment ratio and recovery percentage of SDS
were increased and SDS concentration of the residual solution was decreased at its lowest concentration.
Materials method: The effects of SDS concentration and superficial gas velocity on foaming height and
enrichment ratio of SDS were studied in order to determine the lowest SDS concentration in foam separation.
A two-stage foam separation technology using only one column was developed to improve the performances
at the lowest SDS concentration.
Results: The results showed that the lowest SDS concentration in foam separation was 50 mg/L. In the onestage
foam separation, SDS surface excess increased with increasing the height of the liquid phase and the
pore diameter of gas distributor, thus enrichment ratio increased from 1.9 to 7.2 and however, recovery percentage
decreased and SDS concentration of the residual solution significantly increased. In the developed
two-stage foam separation, enrichment ratio and recovery percentage increased to 28.0 and 94.2%, respectively
and at the sametime, SDS concentration of the residual solution decreased to 6.0 mg/L under the operating
conditions of SDS concentration of the feed solution of 50.0 mg/L, loading volume of 0.630 L and
superficial gas velocity of 1.33 mm/s.