Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, QC, H3G 1M8, Canada.
Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, QC, H3G 1M8, Canada.
Chemosphere. 2022 Feb;288(Pt 3):132628. doi: 10.1016/j.chemosphere.2021.132628. Epub 2021 Oct 20.
The released oil can affect the vulnerable shoreline environment if the oil spills happen in coastal waters. The stranded oil on shorelines is persistent, posing a long-term influence on the intertidal ecosystem after weathering. Therefore, shoreline cleanup techniques are required to remove the oil from the shoreline environment. In this study, a new shoreline cleanup initiative using chitosan/rhamnolipid (CS/RL) complex dispersion with pH-stimulus response was developed for oiled sand cleanup. The results of factorial and single-factor design revealed that the CS/RL complex dispersion maintained high removal efficiency for oiled sand with different levels of oil content in comparison to using rhamnolipid alone. However, the increase of salinity negatively affected the removal efficiency. The electrostatic screening effect of high ionic strength can hinder the formation of the CS/RL complex, and thus reduce removal efficiency. The pH-responsive characteristic of chitosan allows the easy separation of water and oil in washing effluent. The chitosan polyelectrolytes aggregated and precipitated due to the deprotonation of amino groups by adjusting the pH of the washing effluent to above 8. The microscope image demonstrated that the chitosan aggregates wrapped around the oil droplets and settled to the bottom together, thus achieving oil-water separation. Such pH-stimulus response may help achieve an easy oil-water separation after washing. These findings have important implications for developing the new strategies of oil spill response.
如果石油泄漏发生在沿海水域，释放的石油可能会影响脆弱的海岸线环境。搁浅在海岸线上的石油具有持久性，在风化后会对潮间带生态系统产生长期影响。因此，需要采用海岸线清理技术来清除海岸线环境中的石油。在这项研究中，开发了一种使用具有 pH 刺激响应的壳聚糖/鼠李糖脂（CS/RL）复合分散体的新海岸线清理方法，用于清理含油沙土。析因和单因素设计的结果表明，与单独使用鼠李糖脂相比，CS/RL 复合分散体在处理不同含油程度的含油沙土时保持了较高的去除效率。然而，盐度的增加会对去除效率产生负面影响。高离子强度的静电屏蔽效应会阻碍 CS/RL 复合物的形成，从而降低去除效率。壳聚糖的 pH 响应特性允许在洗涤废水中轻松实现油水分离。通过调节洗涤废水的 pH 值至 8 以上，壳聚糖聚电解质由于氨基脱质子化而聚集和沉淀。显微镜图像表明，壳聚糖聚集物包裹在油滴周围，并一起沉降到底部，从而实现油水分离。这种 pH 刺激响应可能有助于在洗涤后实现轻松的油水分离。这些发现对于开发新的溢油应急策略具有重要意义。
