Triton Xs （TXs） surfactants/cosurfactant/water/oil （toluene） microemulsion systems for enhancing toluene solubilization were proposed and its potential was investigated for toluene removal from gas stream. The results indicated that TX-100 was superior to other TXs surfactants in removing toluene without cosurfactant. The efficiency of cosurfactants for improving toluene solubilization capacity follows the order： amine 〉 alcohol 〉 acid. According to the factor analysis, the linear cosurfactants are better than the branched ones. The effects of hydrophile-lipophile balance （HLB）, salt （NaCl） concentration and temperature on the formation of microemulsion system were also discussed. The results suggested that the optimum value of HLB was 15, the effect of NaCl concentration on the system was inconspicuous and the lower temperature enhanced the solubilization capacity. Nonionic surfactant-based microemulsions had a significant absorption enhancement for toluene, indicated by as much as 82.72% of toluene in phase composition diagram, which will have a great prospect in air pollution treatment.
Lian Liu,Senlin Tian ,Ping Ning Faculty of Environmental Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China
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 （I 2＋ ） 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 I 2＋ 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.
