Chemical and Materials Engineering Department, University Complutense of Madrid, 28040 Madrid, Spain.
Int J Environ Res Public Health. 2020 Jun 23;17(12):4494. doi: 10.3390/ijerph17124494.
Application of surfactants in the remediation of polluted sites with dense nonaqueous phase liquid (DNAPL) still requires knowledge of partitioning between surfactants and pollutants in the organic and aqueous phases and the time necessary to reach this balance. Two real DNAPLs, generated as wastes in the lindane production and taken from the polluted sites from Sabiñanigo (Spain), were used for investigating the solubilization of 28 chlorinated organic compounds (COCs) applying aqueous surfactant solutions of three nonionic surfactants (E-Mulse 3 (E3), Tween80 (T80), and a mixture of Tween80-Span80 (TS80)) and an anionic surfactant (sodium dodecyl sulfate (SDS)). The initial concentrations of surfactants were tested within the range of 3-17 g·L. The pH was also modified from 7 to >12. The uptake of nonionic surfactants into the organic phase was higher than the anionic surfactants. Solubilization of COCs with the nonionic surfactants showed similar molar solubilization ratios (MSR = 4.33 mmolg), higher than SDS (MSR = 0.70 mmolg). Furthermore, under strong alkaline conditions, the MSR value of the nonionic surfactants was unchanged, and the MSR of SDS value increased (MSR = 1.32 mmolg). The nonionic surfactants did not produce preferential solubilization of COCs; meanwhile, SDS preferentially dissolved the more polar compounds in DNAPL. The time required to reach phase equilibrium was between 24 and 48 h, and this contact time should be assured to optimize the effect of the surfactant injected on COC solubilization.
表面活性剂在受密集非水相液体 (DNAPL) 污染的场地修复中的应用仍需要了解表面活性剂与有机相和水相中的污染物之间的分配情况，以及达到平衡所需的时间。两种真实的 DNAPL，分别作为林丹生产过程中的废物和从西班牙萨比尼戈污染场地中提取的，用于研究应用三种非离子表面活性剂（E-Mulse 3 (E3)、吐温 80 (T80) 和吐温 80-司盘 80 (TS80)）和一种阴离子表面活性剂（十二烷基硫酸钠 (SDS)）的水溶液对 28 种氯化有机化合物 (COC) 的增溶作用。表面活性剂的初始浓度在 3-17 g·L 范围内进行了测试。还从 7 到 >12 对 pH 值进行了调整。非离子表面活性剂进入有机相的吸收量高于阴离子表面活性剂。非离子表面活性剂对 COC 的增溶显示出相似的摩尔增溶比 (MSR = 4.33 mmol·g)，高于 SDS (MSR = 0.70 mmol·g)。此外，在强碱性条件下，非离子表面活性剂的 MSR 值保持不变，而 SDS 的 MSR 值增加（MSR = 1.32 mmol·g）。非离子表面活性剂对 COC 没有表现出优先增溶作用，而 SDS 优先溶解 DNAPL 中极性更强的化合物。达到相平衡所需的时间为 24 至 48 小时，应确保这段接触时间以优化注入表面活性剂对 COC 增溶的效果。
