[Effect of surfactant on the evaporation of BTEX from static water]

Effect of surfactant on the evaporative loss of benzene, toluene and ethylbenzene from static water was researched and the mechanism of surfactant was studied, so as try to supply theoretical reference for the effect of surfactant on the evaporation of complex pollution in water system. Sodium dodecylbenzene sulfonate (SDBS), cetyltrimethyl ammonium bromide (CTMAB) and polyoxyethylene(4) lauryl ether(Brij30) were used in the experiment. The results show when the surfactant concentrations exceeded their critical micelle concentrations (CMCs) and were set above 1 000mg/L, 2 000mg/L and 3 000mg/L respectively, the evaporative loss velocity of ethylbenzene, toluene and benzene began to decrease and their half-lives prolonged consequently. The main reason for the decrease of the evaporative loss velocity of BTEX was surfactant micelles formed and it caused the ratio of the concentration of BTEX at the liquid surface to that at the bulk liquid phase to diminish. Comparing CTMAB and Brij30 with SDBS, the evaporative loss of BTEX from static water decreased more evidently in CTMAB and Brij30 solutions. The positive relation was found between the restraining ability of a surfactant and the octanol-water partition coefficients or Henry's law constants of BTEX.