On solubilization of DNAPLs by mixed anionic-nonionic surfactants
DONG Wen-juan, ZHAO Bao-wei, JIANG Bing, XU Jin(School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China)
Surfactant-enhanced remediation (SER) is considered to be one of the effective approaches to removing the absorbed hydrophobic organic compounds from the contaminated soils. The present paper is just aimed at studying the solubilization of DNAPLs through mixed anionic-nonionic surfactants experiments with chlorobenzene (CB), 1,2-dichlorobenzene (1,2-DCB) and trichloroethylene (TCE) by micellar solutions of single anionic surfactant sodium dodecyl sulfate (SDS) and single nonionic surfactant (TW80) and/or the mixed anionic-nonionic surfactants with a static equilibrium method. It has also investigated the influence of inorganic ions Na+, Mg2+ and Ca2+ upon the solubilization. As a result, our study enables us to supply a new remediation method for the contaminated soil and groundwater by dense non-aqueous phase liquids (DNAPLs). Our study results also prove that the solubilization effect of the organic contaminants by the mixed surfactants can significantly be enhanced compared with the single anionic surfactant SDS. Whereas the critical micellar concentration (CMC) can be decreased, the solubility can be increased as long as the mass ratio of nonionic surfactant increases. As the solubility enhancement efficiency of the different compounds follow the order of TCECB1, 2-DCB, the partition coefficient (Kmc) between the micellar phase and water by the surfactant can be made near to octanol-water partition coefficient (Kow). In addition, the weight of the solubilization ratio (WSR) appears to be positively relative to the water solubility of the organic contaminants and negatively correlates to Kmc, Kow, the molar volume of the solutes and the hydrophile-lypophile balance value (HLB) of the surfactant. Na+, Mg2+ and Ca2+ can increase the apparent solubility of CB in the surfactant. Thus, it can be seen that the mixed surfactant can prove to be able to greatly enhance the resistance to hard water and heighten the solubilization effect.
【Fund】： 国家自然科学基金项目(20577018);; 甘肃省中青年科技基金项目(3ZS042-B25-023);; 兰州交通大学“青蓝”人才工程项目
【CateGory Index】： X53
【CateGory Index】： X53