Effects of surfactant contamination on oxygen mass transfer in fine bubble aeration process

Abstract

The effects of anionic, cationic, and non-ionic surfactants (SDS, SDBS, CTAB and Tween20) on oxygen mass transfer (OMT) in fine bubble aeration systems were investigated. The overall gas-liquid volumetric mass transfer coefficient (KLa), specific interfacial area (a), and liquid-side mass transfer coefficient (KL) parameters were used to assess the influence of the surfactants. At the same concentration, the different surfactants were observed to influence the KLa value as follows: KLa (SDBS)>KLa (SDS)>KLa (tween20)>KLa (CTAB). For all used surfactants, the overall trends showed a significant decrease in the KLa value at low concentrations (0–5mg/L), while the KLa value recovered somewhat at high concentrations (10–20mg/L). The decrease to the KL value was found to be much larger than increase in the a value in the presence of surfactants. Furthermore, a simple model was established that provides an OMT prediction for different surfactants.