Oxidation of sodium sulphide in a foam bed contactor

Abstract

Oxidation of sodium sulphide to sodium thiosulphate has been experimentally investigated in a foam bed contactor using air as the oxidizing medium. The variables studied are superficial air velocity, initial sulphide concentration, height of the foam bed, and the nature of the surfactant. The results indicate that the conversion increases with increase in the superficial air velocity and initial sulphide concentration. The nature of the surfactant has considerable influence on the conversion, even when their surface resistance is negligible. When sodium dodecyl sulphate is used as a surfactant, the conversion decreases as the foam height increases. Opposite trend has been observed when octyl phenoxy polyethoxyethanol is used. The apparently contradictory results are satisfactorily explained on the basis of a simplified single-stage model of a foam bed contactor.