Effects of surfactants and salt on Henry's constant of n-hexane.
n-Hexane biological removal is intrinsically limited by its hydrophobic nature and low bioavailability. The addition of surfactants could enhance the transport of volatile organic compounds (VOCs) and change the gas-liquid equilibrium of VOCs. In this paper, the effects of four surfactants, sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), tert-octylphenoxypoly-ethoxyethanol (Triton X-100), polyoxyethylene (20) sorbitan monooleate (Tween 80), and sodium nitrate on apparent Henry's constant of n-hexane in surfactant solutions were investigated. The apparent Henry's constants were significantly reduced when surfactants concentrations exceeded their critical micelle concentrations (cmc's). On a cmc basis, the anionic surfactant SDS was found to have the greatest effect on the apparent Henry's constant with CTAB succeeding, then followed by Triton X-100 and Tween 80. However, the apparent Henry's constant of n-hexane decreased even more rapidly when Triton X-100, a nonionic surfactant, was added than when the ionic surfactant of SDS or CTAB was applied under identical mass concentration and other conditions. These results suggest that Triton X-100 have the biggest solubilization of n-hexane among the four surfactants. Sodium nitrate slightly decreased the apparent Henry's constant of n-hexane in surfactant solutions, and could be considered as a cosolvent in the surfactant-(n-hexane) solution. In addition, the relationship between apparent Henry's constant and surfactant concentration was further developed.
Yang
Chunping
C
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China. chunpingyang@gmail.com
Chen
Fayuan
F
Luo
Shenglian
S
Xie
Gengxin
G
Zeng
Guangming
G
Fan
Changzheng
C
D000838:Anions; D001682:Biological Availability; D002627:Chemistry, Physical / Q000379:methods; D005740:Gases; D006586:Hexanes / Q000737:chemistry*; D007477:Ions; D008823:Micelles; D009566:Nitrates / Q000737:chemistry; D017830:Octoxynol / Q000494:pharmacology; D009930:Organic Chemicals / Q000737:chemistry / Q000302:isolation & purification; D011136:Polysorbates / Q000494:pharmacology; D012492:Salts / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D000838:Anions; D005740:Gases; D006586:Hexanes; D007477:Ions; D008823:Micelles; D009566:Nitrates; D009930:Organic Chemicals; D011136:Polysorbates; D012492:Salts; D013501:Surface-Active Agents; D014867:Water; C026385:n-hexane; C031618:sodium nitrate; D017830:Octoxynol