Henry's Law Constants and Micellar Partitioning of Volatile Organic Compounds in Surfactant Solutions

• Published in: Journal of chemical and engineering data 2000-01, Vol.45 (1), p.38-47
• Main Authors: Vane, Leland M, Giroux, Eugene L
• Format: Article
• Language: English
• Subjects: Chemistry; CHLORINATED ALIPHATIC HYDROCARBONS; ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; ENVIRONMENTAL TRANSPORT; Exact sciences and technology; General and physical chemistry; Liquid-vapor equilibria; MICELLAR SYSTEMS; PARTITION; Phase equilibria; REMEDIAL ACTION; SURFACTANTS; TOLUENE; VOLATILE MATTER
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/je990195u

Partitioning of volatile organic compounds (VOCs) into surfactant micelles affects the apparent vapor−liquid equilibrium of VOCs in surfactant solutions. This partitioning will complicate removal of VOCs from surfactant solutions by standard separation processes. Headspace experiments were performed to quantify the effect of four anionic surfactants and one nonionic surfactant on the Henry's law constants of 1,1,1-trichloroethane, trichloroethylene, toluene, and tetrachloroethylene at temperatures ranging from 30 to 60 °C. Although the Henry's law constant increased markedly with temperature for all solutions, the amount of VOC in micelles relative to that in the extramicellar region was comparatively insensitive to temperature. The effect of adding sodium chloride and isopropyl alcohol as cosolutes also was evaluated. Significant partitioning of VOCs into micelles was observed, with the micellar partitioning coefficient (tendency to partition from water into micelle) increasing according to the following series:  trichloroethane < trichloroethylene < toluene < tetrachloroethylene. The addition of surfactant was capable of reversing the normal sequence observed in Henry's law constants for these four VOCs.