Molecular Interactions and Modeling of Anionic Surfactant Effect on Oxygen Transfer in a Cylindrical Reactor

In this work, effects of anionic surfactant on the oxygen transfer is investigated in a cylindrical reactor. For the first time, a systematic study in a wide surfactant concentration range, below and above the critical micellar concentration, is shown. A maximum reduction in the volumetric mass transfer coefficient (K(L)a) was observed for a surfactant concentration of 0.07 mM, before the CMC. Results are discussed based on the molecular interactions among water, air bubbles, and surfactant molecules. To better understand the experimental findings, a mathematical model was developed based on the estimated volumetric mass transfer coefficient. Predictions agree very well with the experimental results and point to a maximum reduction of 41% in the K(L)a, regardless of the inlet airflow rate in the reactor. We believe that our model can be used to predict future experimental results. In addition, this work can also be useful to better design an aerobic system.