Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China.
Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China.
J Environ Manage. 2024 May;358:120888. doi: 10.1016/j.jenvman.2024.120888. Epub 2024 Apr 13.
Oil dispersion, a crucial process in oil transport, involves the detachment of oil droplets from slicks and their introduction into the water column, influencing subsequent oil migration and transformation. This study examines oil dispersion, considering characteristics, stability, and mechanisms, while evaluating the impact of dispersants and salinity. Results show the significant role of surfactant type in dispersants on oil dispersion characteristics, with anionic surfactants exhibiting higher sensitivity to salinity changes compared to nonionic surfactants. The dispersion efficiency varies with salinity, with anionic surfactants performing better in low salinity (<20‰) and nonionic surfactants showing superior performance at 30-35‰ salinities. Rheological analysis illustrates the breakup and coalescence of oil droplets within the shear rates of breaking waves. An increase in interfacial film rigidity impedes the coalescence of oil droplets, contributing to the dynamic stability of the oil-water hybrid system. The use of GM-2, a nonionic dispersant, results in the formation of a solid-like interface, characterized by increased elastic modulus, notably at 20‰ salinity. However, stable droplet size distribution (DSD) at 35‰ salinity for 60 h suggests droplets can remain dispersed in seawater. The enhancement of stability of oil dispersion is interpreted as the result of two mechanisms: stabilizing DSD and developing the strength of viscoelastic interfacial film. These findings offer insights into oil dispersion dynamics, highlighting the importance of surfactant selection and salinity in governing dispersion behavior, and elucidating mechanisms underlying dispersion stability.
油分散作用是石油运输中的关键过程，涉及到油滴从浮油中脱离并进入水柱中，影响后续的石油迁移和转化。本研究考察了油分散作用，考虑了其特性、稳定性和机制，并评估了分散剂和盐度的影响。结果表明，表面活性剂类型在分散剂对油分散特性的影响中起着重要作用，与非离子型表面活性剂相比，阴离子型表面活性剂对盐度变化更为敏感。分散效率随盐度变化而变化，阴离子型表面活性剂在低盐度（<20‰）下表现更好，而非离子型表面活性剂在 30-35‰盐度下表现出更好的性能。流变分析表明，在破波剪切率范围内，油滴会发生破裂和聚并。界面膜刚性的增加会阻碍油滴的聚并，有助于油-水混合体系的动态稳定性。使用非离子型分散剂 GM-2 会导致形成固态界面，其弹性模量在 20‰盐度下显著增加。然而，在 35‰盐度下，60 小时后稳定的液滴尺寸分布（DSD）表明，油滴可以在海水中保持分散状态。油分散稳定性的增强被解释为两种机制的结果：稳定 DSD 和增强粘弹性界面膜的强度。这些发现为油分散动力学提供了深入的了解，强调了表面活性剂选择和盐度在控制分散行为中的重要性，并阐明了分散稳定性的机制。
