Removalof Cadmium(II) from Aqueous Solution by Ion Flotation Using RhamnolipidBiosurfactant As an Ion Collector.

Inthis research, the potential of cadmium removal from aqueous solutionby foam flotation with a rhamnolipid biosurfactant sample was studied.The effects of different major operating conditions, such as rhamnolipidand cadmium concentrations, solution pH, aeration rate, and frothertype and concentration, on the cadmium removal were investigated.The selectivity coefficients in the presence of rhamnolipid maintaineddefinite orders as follows: cadmium > zinc, cadmium > copper,and zinc > copper. The selectivity coefficient of cadmium overcopper was the highest one. The maximum removals of Cd from cleanand Zn- and Cu-contaminated solutions were about 57%, 36%, and 48%,respectively. Kinetic studies indicated that ion flotation of cadmiumfollows a first-order equation with a kinetic rate of 0.0071 min–1. Although the removals are rather low, it seems thatthe use of rhamnolipid biosurfactant can be promising in heavy-metalremoval from wastewaters by foam flotation with some modifications. [ABSTRACT FROM AUTHOR]