Water solubility enhancements of pyrene by single and mixed surfactant solutions

Article type: Research Article

Authors: Zhu, Li-zhong | Chiou, Cary T.

Affiliations: Department of Environmental Science, Zhejiang University, Hangzhou 310028, China. E-mail: lzzhu@mail.hz.zj.cn | U.S.Geological Survey, Box 25046, MS 408, Denver Federal Center, Denver, Colorado 80225, USA

Abstract: Water solubility enhancements of pyrene by both single-surfactant and mixed-surfactant solutions were compared andevaluated. The solubility of pyrene in water was greatly enhanced by each of Triton X-100 (TX100), Triton X-405 (TX405), Brij 35 and SDS, in which the water solubility enhancements increased with increasing surfactant concentrations. The extent of solubility enhancements at surfactant concentrations below the CMC is the order of TX100 > Brij 35 > TX405 > SDS; the sequence at surfactantconcentrations above the CMC is TX100 > Brij 35 > SDS > TX405. Pyrene was solubilized synergistically by anionic-nonionic mixed surfactant solutions, especially at low surfactant concentrations. The synergistic power of the mixed surfactants is SDS-TX405 > SDS-Brij 35 > SDS-TX100. The synergism as noted is attributed to increasing Kmc and/or decreasing the CMC of the mixed surfactan solution. For SDS-TX405 and SDS-Brij 35 mixed surfactant solutions, an increase in Kmc is coupled with a decrease in the CMC; for SDS-TX100, only a decreased in the CMC value is noted. Mixed-surfactant solutions may improve the performance of the surfactant-enhanced remediation (SER) of soils by increasing the bioavailability and biodegradation of non-aqueous-phase organic pollutants and reducing the level of surfactant pollution and remediation expenses.

Keywords: water solubility enhancements, pyrene, single-surfactant solution, mixed surfactant solution

Journal: Journal of Environmental Sciences, vol. 13, no. 4, pp. 491-496, 2001