Efficient foam separation was achieved by dual CCC through a long multilayer coil mounted on the cross-axis synchronous flow- through coil planet centrifuge (X-axis CPC). A series of preliminary experiments was performed to investigate various physical factors such as revolutional speed, liquid feed rate, N2 gas feed pressure, etc., to optimize operational conditions. Potential capability of the method was demonstrated in separations of two sets of test samples using sodium dodecyl sulfate (SDS) as a foaming agent. Rhodamine B with high foam affinity was quickly separated from Evans blue lacking foam affinity. A high concentration of salts such as Na2HPO4 in the surfactant solution effectively lowered the foam affinity of basic dyes, thus yielding complete peak resolution of two basic dyes, rhodamine B and methylene blue, according to a subtle difference in foam affinity.
