不同溶液对地下水中甲基叔丁基醚溶解过程影响

采用实验室小型二维砂箱对地下水流动过程中甲基叔丁基醚(MTBE)溶解过程进行模拟实验,主要考察了非离子型表面活性剂聚乙氧基油酸山梨糖醇(Tween80)、阴离子表面活性剂十二烷基苯磺酸钠(SDBS)与助溶剂乙醇对MTBE溶解过程的影响。结果表明,Tween80在其临界胶束浓度(CMC)以上能够对MTBE起到增溶的效果而且在所研究浓度范围存在最佳增溶浓度10g/L;低于临界胶束浓度条件下的SDBS并没有增强MTBE迁移反而会延缓MTBE的溶解;乙醇可以增大MTBE的溶出浓度,而且随着含量提高增溶效果加强。通过比较各种条件下最佳的MTBE累积去除率可以得出,当MTBE去除率达到80%之前,对MTBE溶解增强效果由大到小顺序依次为:非离子型表面活性剂Tween80> 助溶剂乙醇> 水> 阴离子表面活性剂SDBS;而去除率80%以后,增溶效果的顺序则为乙醇> Tween80> 水> SDBS。

Effects of different solution on MTBE dissolution in subsurface

A two-dimension laboratory scale sandbox was manufactured to model the dissolution process of methyl-tert-butyl ether(MTBE)in subsurface. A serial of experiments were conducted to investigate the influences of nonionic surfactant Polysorbate 80(Tween80), anionic surfactant Sodium Dodecylbenzenesulfonate(SDBS)and cosolvent ethanol on MTBE dissolution. The results indicated that Tween80 can promote MTBE dissolution above Critical Micelle Concentration(CMC)and the optimal concentration was 10g/L within the experimental concentration range;SDBS prolonged the time for complete dissolution of MTBE without enhancement of MTBE mobility below Critical Micelle Concentration;ethanol can enhance MTBE dissolution byhigh dissolution concentration and effectiveness was increased with the increase of ethanol content. By comparing the best MTBE removals under different conditions, the following results were obtained. Before 80% of MTBE was dissolved, the descending order for enhancement effects of MTBE dissolution was:nonionic surfactant Tween80> cosolvent ethanol> water> anionic surfactant SDBS. However, after removal rate was greater than80%, the order was:cosolvent ethanol> nonionic surfactant Tween80> water> anionic surfactant SDBS.