阴/非表面活性剂对土壤中菲的洗脱及影响因素研究

A Comparative Study of Washing Effects of Phenanthrene in the Soils by Anionic/Nonionic Surfactants

通过对不同浓度、不同配比的表面活性剂溶液中的含菲土壤进行振荡、离心等方法,比较研究了十二烷基苯磺酸钠(sodiumdo declbenzyl sulfonate,SDBS)、辛基酚聚氧乙烯醚(octylphenoxypolyethoxyethanol,TX100)及其混合表面活性剂(SDBS-TX100)对土壤中菲的洗脱作用,重点研究了表面活性剂浓度、清洗时间、土壤种类、无机盐等因素的影响。结果表明,随着单一非离子表面活性剂(TX100)和混合表面活性剂(SDBS-TX100)浓度的增大,菲洗脱率不断增大,当浓度为4000mg·L-1时达到平衡;对于阴离子表面活性剂(SDBS),随着浓度的增大菲洗脱率直到浓度为8000mg·L-1仍在增大。1∶10土水比条件下,清洗时间为40min时,单一阴、非表面活性剂和混合表面活性剂对污染土壤中菲的洗脱能力分别达到最高。土壤有机质含量较低有利于表面活性剂对菲的洗脱作用。一定浓度的无机盐离子Na+、Ca2+和Mg2+的存在可使阴离子表面活性剂产生沉淀,大大影响了表面活性剂的洗脱能力,但阴/非混合表面活性剂(SDBS-TX100)可降低沉淀损失,提高对菲的洗脱作用。

Polynnelear aromatic hydrocarbons（PAHs）are ubiquitous and persistent since they could not be easily decomposed in soil. Therefore, clean-up of PAHs contaminated sites is an urgent task. Surfactant-enhaneed soil washing is considered with increasing frequency to access soil-contaminant separation. In this study, the wash of phenanthrene in the soils by anionic/nonionic mixed surfactants that were consist of sodium dodeclbenzyl sulfonate （SDBS）and octylphenoxypolyethoxyethanol （TX 100） （SDBS-TX 100）, was studied and compared individually with the suffaetants. The wash of phenanthrene in the soils was influenced by many factors, including suffactant concentrations, washing time, soil types and inorganic salts. The phenanthrene concentrations in water phase increased obviously with the increase of the nonionic suffactant（TX 100 ）and mixed suffactants （SDBS-TX100）concentrations. When the concentration was 4 000 mg· L^-1 the washing efficiency was balanced. But the wash efficiency of phenanthrene increased constantly until the surfaetant concentrations approached 8 000 mg· L^-1 for anionic surfactant（SDBS）. When the ratio of soil-water system was 1 to 10 and washing time reached 40 min, the washing efficiency of phenanthrene in the soils using single and anionic/nonionic mixed suffactants when concentrations were 1 000 mg·L^-1 distincly achieves the maximum. The washing efficiency of phenanthrene could be enhanced by the soils with lower organic matter. Na^＋, Ca^2＋ and Mg^2＋ with certain concentrations in the soils may precipitate with anionic surfactants, which could decrease the phenanthrene concentration in water phase, but it was increased by anionic/nonionic mixed surfactants（SDBS-TX100）which could reduce the precipitation. The results show that anionic/ nonionic surfactants could exhibit potential application in the enhanced soil.