title: Reversibly enhanced aqueous solubilization of volatile organic compounds using a redox-reversible surfactant.
abstract: Surfactant-enhanced remediation (SER) is an effective method for the removal of volatile organic compounds (VOCs) from contaminated soils and groundwater. To reuse the surfactant the VOCs must be separated from the surfactant solutions. The water solubility of VOCs can be enhanced using reversible surfactants with a redox-acive group, (ferrocenylmethyl)dodecyldimethylammonium bromide (Fc12) and (ferrocenylmethyl)tetradecanedimethylammonium bromide (Fc14), above and below their critical micelle concentrations (CMC) under reducing (I+) and oxidative (I2+) conditions. The CMC values of Fc12 and Fc14 in I+ are 0.94 and 0.56 mmol/L and the solubilization of toluene by Fc12 and Fc14 in I+ for toluene is higher than the solubilization achieved with sodium dodecyl sulfate, cetyltrimethylammonium bromide and Trition X-114. The solubilization capacity of the ferrocenyl surfactants for each tested VOCs ranked as follows: ethylbenzene > toluene > benzene. The solubilities of VOCs by reversible surfactant in I+ were 30% higher than those in I2+ at comparable surfactant concentrations. The effects of Fc14 concentrations on VOCs removal efficiency were as follows: benzene > toluene > ethylbenzene. However, an improved removal efficiency was achieved at low ferrocenyl surfactant concentrations. Furthermore, the reversible surfactant could be recycled through chemical approaches to remove organic pollutants, which could significantly reduce the operating costs of SER technology.
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China. liyingjie08@163.com
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Li
authors.forename: Senlin
authors.initials: S
authors.lastname: Tian
authors.forename: Hong
authors.initials: H
authors.lastname: Mo
authors.forename: Ping
authors.initials: P
authors.lastname: Ning
mesh_terms: D007455:Iodine / Q000737:chemistry; D008823:Micelles; D010084:Oxidation-Reduction; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry* / Q000302:isolation & purification; D012995:Solubility; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*; D055549:Volatile Organic Compounds / Q000737:chemistry* / Q000302:isolation & purification; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D008823:Micelles; D012989:Soil Pollutants; D013501:Surface-Active Agents; D055549:Volatile Organic Compounds; D014874:Water Pollutants, Chemical; D014867:Water; D010767:Phosphorylcholine; C028810:dodecylphosphocholine; D007455:Iodine