Turner Andrew, Xu Jing
School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK.
Water Res. 2008 Jan;42(1-2):318-26. doi: 10.1016/j.watres.2007.07.018. Epub 2007 Jul 25.
The influence of sub-micellar concentrations of an anionic surfactant (sodium dodecyl sulphate; SDS) and a cationic surfactant (hexadecyl trimethylammonium bromide; HDTMA) on the aquatic behaviour of the strongly complexing metals, Pd(II) and Hg(II), has been investigated. In river water, flocculation of organic complexes of metal was suppressed by SDS but accentuated by HDTMA, effects that are consistent with electrostatic and hydrophobic interactions between ionic surfactants and natural polyelectrolytes. In sea water, flocculation of metal complexes was enhanced by both surfactants because of the shielding and salting effects of inorganic ions on these interactions. Particle surface modification engendered by sorbed surfactant strongly influenced the sorption of Pd and Hg to estuarine particles. Thus, hydrophobically bound SDS enhances the negative charge at the particle surface and favours specific sorption of metal, while specifically sorbed HDTMA enhances the solvency of the particle surface, favouring non-specific sorption of metal complexes. Given the relatively short environmental half-life of SDS, its impacts on strongly complexing metals are predicted to be localised. However, greater stability of HDTMA suggests that its effects on such metals, including enhanced flocculation and sorption, are likely to be more pervasive.
研究了亚胶束浓度的阴离子表面活性剂（十二烷基硫酸钠；SDS）和阳离子表面活性剂（十六烷基三甲基溴化铵；HDTMA）对强络合金属钯（II）和汞（II）水生行为的影响。在河水中，SDS抑制了金属有机络合物的絮凝，但HDTMA加剧了这种絮凝，这些效应与离子表面活性剂和天然聚电解质之间的静电和疏水相互作用一致。在海水中，由于无机离子对这些相互作用的屏蔽和盐析作用，两种表面活性剂都增强了金属络合物的絮凝。吸附的表面活性剂引起的颗粒表面改性强烈影响钯和汞对河口颗粒的吸附。因此，疏水结合的SDS增加了颗粒表面的负电荷，有利于金属的特异性吸附，而特异性吸附的HDTMA增加了颗粒表面的溶剂化能力，有利于金属络合物的非特异性吸附。鉴于SDS在环境中的半衰期相对较短，预计其对强络合金属的影响是局部的。然而，HDTMA的稳定性更高，这表明其对此类金属的影响，包括增强的絮凝和吸附，可能更普遍。
