Simultaneous Removal of Naphthalene and Sulfur Dioxide using Surfactant

Anionic surfactant was added during absorption to investigate the solubility of vapor phase naphthalene and SO2 in water. Anionic surfactant employed was sodium dodecyl sulfate. Lower than critical micelle concentration (CMC), the apparent solubility and absorption rates of SO2 or naphthalene with or without SO2 were practically identical to those of pure water. However, higher than CMC, equilibrium SO2 or naphthalene apparent solubility increased linearly in proportion to the surfactant concentrations. The solubilization effect of micelles resulted in the increase. Because the micelle solubilization effect was greater than that of the decrease of the mass transfer coefficient, the gas absorption rate increased. When surfactant concentration was 0.1 M, the enrichment factor (EF) value of naphthalene with SO2 was 4.54, which was only half of its value without SO2. When surfactant concentration was 0.2 M, the SO2 EF values increased to 2.24. These empirical findings confirm that to increase the removal efficiency of simultaneous absorption of hydrophobic organic compounds and SO2 via a spray or packed tower, an anionic surfactant can be employed.