Volume 12, No. 4, August 2012, Pages 526-535 PDF(299 KB)
Emissions of Organic Compounds in Surfactant Solutions under Air Turbulence
Department of Bioenvironmental Engineering, Chung Yuan Christian University, Chung-Li, 32023, Taiwan
The objective of this study was to investigate the effects of surfactants aggregating the gas-liquid interface on the volatilization rates of the organic compounds. The changes in the overall mass transfer coefficient (KOL) and concentration at gas-liquid interface of organic compounds in surfactant (dodecylbenzene sulfonic acid sodium, DBS) solutions under wind speed conditions were used to elucidate the results. The studied compounds consisted of aromatic compounds, benzene, toluene, ethylbenzene, m-dichlorobenzene, and propylbenzene with relatively higher Henry’s law constants (H) and water solubilities (Sw), and chlorinated pesticides, α-endosulfan, heptachlor epoxide, endrin, and dieldrin, with relatively lower H and Sw. Various surfactant concentrations, from 0 to 1000 mg/L under various wind speeds from 0 to 6.0 m/s, were used to examine the influence of the surfactant on the volatilization of the test organic compounds. The results indicated that the surfactant in the solution suppressed the volatilization of organic compounds. The degree of volatilization reduction was inversely proportional to the Sw values of the test organic compounds. The curve profiles for the KOL values of the organic compounds in the surfactant solutions, relative to the selected wind speed, were divided into the following two stages: the sharp-rise stage and the stable-linearity stage. The critical finding was that the surfactant markedly enhanced the concentrations of the low Sw compounds at the interface. The wind may cause an unexpected increase in the KOL value of the low Sw compound in the solution that contains a high surfactant concentration.
Volatilization rate; Volatilization reduction; Surfactants; Wind; Interface concentration.