National Center of Excellence for Environmental and Hazardous Waste Management, Chulalongkorn University, Bangkok 10330, Thailand.
J Colloid Interface Sci. 2010 Apr 1;344(1):126-31. doi: 10.1016/j.jcis.2009.10.035. Epub 2009 Nov 17.
Surfactant-based adsorption processes have been widely investigated for environmental applications. A major problem facing surfactant-modified adsorbents is surfactant loss from the adsorbent due to loss of monomers from solution and subsequent surfactant desorption. For this study, a bilayer of anionic polymerizable surfactant (Hitenol BC 05, Hitenol BC 10 and Hitenol BC 20) and non-polymerizable surfactant (Hitenol N 08) was adsorbed onto alumina. The results of adsorption studies showed that as the number of ethylene oxide (EO) groups of the surfactants increased, the area per molecule increased and the maximum adsorption decreased. The lowest maximum adsorption onto alumina was for Hitenol BC 20 (20 EO groups) corresponding to 0.08 mmol/g or 0.34 molecule/nm(2) while the highest level of adsorption was 0.30 mmol/g or 1.28 molecule/nm(2) for Hitenol BC 05 (5 EO groups). This variation in adsorption was attributed to the increased bulkiness of the head group with increasing number of EO groups. Relative to the adsolubilization capacity of organic solutes, ethylcyclohexane adsolubilizes more than styrene. Styrene and ethylcyclohexane adsolubilization were both independent of the number of EO groups of the surfactant. For surfactant desorption studies, the polymerization of polymerizable surfactants increased the stability of surfactants adsorbed onto the alumina surface and reduced surfactant desorption from the alumina surface. These results provide useful information on surfactant-based surface modification to enhance contaminant remediation and industrial applications.
基于表面活性剂的吸附过程已广泛应用于环境应用。表面活性剂修饰吸附剂面临的一个主要问题是由于单体从溶液中损失以及随后的表面活性剂解吸，表面活性剂从吸附剂中损失。在这项研究中，阴离子可聚合表面活性剂（Hitenol BC 05、Hitenol BC 10 和 Hitenol BC 20）和非聚合表面活性剂（Hitenol N 08）的双层被吸附到氧化铝上。吸附研究的结果表明，随着表面活性剂中环氧乙烷（EO）基团数量的增加，分子面积增加，最大吸附量减少。Hitenol BC 20（20 EO 基团）在氧化铝上的最低最大吸附量为 0.08 mmol/g 或 0.34 分子/nm(2)，而 Hitenol BC 05（5 EO 基团）的最高吸附量为 0.30 mmol/g 或 1.28 分子/nm(2)。这种吸附的变化归因于随着 EO 基团数量的增加，头基的体积增加。与有机溶质的增溶能力相比，乙基环己烷的增溶能力大于苯乙烯。苯乙烯和乙基环己烷的增溶能力都与表面活性剂的 EO 基团数量无关。对于表面活性剂的解吸研究，可聚合表面活性剂的聚合增加了吸附在氧化铝表面上的表面活性剂的稳定性，并减少了表面活性剂从氧化铝表面的解吸。这些结果为基于表面活性剂的表面修饰提供了有用的信息，以增强污染物修复和工业应用。
