Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun, 130021, China.
Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Resources, Fuzhou University, Fuzhou, 350108, China.
Environ Pollut. 2020 Oct;265(Pt A):114564. doi: 10.1016/j.envpol.2020.114564. Epub 2020 Apr 9.
In remediation of dense non-aqueous phase liquids (DNAPLs), colloidal biliquid aphrons (CBLAs) could be added to produce a lower density nonaqueous phase which mitigate downward migration of DNAPL to non-polluted aquifers. There is still a big gap in the application of CBLAs in the remediation of actual polluted sites, especially the absence of relevant studies on its transport behavior in the sites, and its structural model has not been fully verified. These two factors could affect the effectiveness of CBLAs in the underground environment and its effect on density control. In this study, we prepared CBLAs with different surfactants and verified the structural model of CBLA based on their particle size distributions and demulsification performance. We studied the effects of particle concentrations, injection velocities, and porous media size on the migration of CBLA using the breakthrough curves and distribution profiles along the column. Experimental results indicated that surface elasticity of CBLAs was inversely proportional to the concentration of the anionic surfactant sodium dodecyl sulphate (SDS), which led to easier demulsification of CBLA with the increase in SDS concentration. This observation was in agreement with the verified structural model of the CBLA which constitute both internal nonionic and external anionic surfactants. Furthermore, CBLA deposition is mainly caused by interception and is not suitable for application in fine media. Low concentration of CBLA and high injection flow rate help CBLA to form a remediation area with a certain radius. This study solved the problem of DNAPLs in contaminated groundwater from the perspective of density regulation, and made contributions towards the development of combined remediation approaches using CBLAs.
在重非水相液体（DNAPLs）的修复中，可以添加胶束双液相乳剂（CBLAs）以产生较低密度的非水相，从而减轻 DNAPL 向下迁移到未污染含水层的程度。然而，CBLAs 在实际污染场地修复中的应用仍然存在很大差距，特别是缺乏其在场地中的迁移行为相关研究，其结构模型也未得到充分验证。这两个因素可能会影响 CBLAs 在地下环境中的有效性及其对密度控制的影响。在本研究中，我们使用不同的表面活性剂制备了 CBLAs，并基于其粒径分布和破乳性能验证了 CBLA 的结构模型。我们通过穿透曲线和沿柱的分布曲线研究了颗粒浓度、注入速度和多孔介质尺寸对 CBLAs 迁移的影响。实验结果表明，CBLAs 的表面弹性与阴离子表面活性剂十二烷基硫酸钠（SDS）的浓度成反比，随着 SDS 浓度的增加，CBLAs 更容易破乳。这一观察结果与 CBLA 的验证结构模型一致，该模型由内部非离子和外部阴离子表面活性剂构成。此外，CBLAs 的沉积主要是由于拦截作用造成的，不适合应用于细颗粒介质。低浓度的 CBLAs 和高注入流速有助于 CBLAs 形成具有一定半径的修复区域。本研究从密度调节的角度解决了污染地下水中的 DNAPLs 问题，为使用 CBLAs 开发联合修复方法做出了贡献。
