Fundamental processes influencing environmentally benign aqueous microemulsion-based methods for bio-oil extraction

CBET 1160053Sabatini植物油提取行业是食品行业挥发性有机化合物排放的主要贡献者。仅在美国，大豆油提取过程中每年的己烷损失就可能高达2.1亿至4.3亿升。关于在植物油提取中使用己烷，人们对健康的担忧越来越多，环境法规也越来越多。暴露在每天15ppm的己烷中三个月已被证明会导致周围神经损伤，己烷也是一种潜在的危险爆炸材料。由于越来越多的环境问题，美国环境保护局(EPA)制定了关于己烷排放的法规。迫切需要更可持续的提取方法来替代己烷。这项研究的总体目标是确定使我们能够开发强大的基于表面活性剂的生物油提取过程的基本过程，包括用于设计一系列生物油的微乳液提取过程的基于基础的模型。本文提出的工作将首次对影响以水相表面活性剂为基础的方法提取生物油的基本过程有一个定量的了解，并将进一步提供一个新的定量模型，该模型可用于在实际条件下对萃取性能进行先验预测。所得到的模型可用于设计基于表面活性剂的多种植物和油料种子的萃取系统，这是目前尚不具备的。这项工作的结果具有潜在的变革性，因为它们将极大地推进生物油的提取方法，从而在整个行业内用更环保的基于水表面活性剂的方法取代环境有害的基于溶剂的方法。油籽浸出的水处理工艺比正己烷更受欢迎，因为它对环境友好、安全，而且产生的油质量上乘。大豆油的酶法浸出效率可达90%以上，但酶辅助浸出过程孵化时间长、温度高、乳状液稳定性差，不利于工业化生产。为了应对这些挑战，该项目将利用生物相容的扩展表面活性剂系统来实现高采油效率，同时避免稳定的乳状液形成。然后将工作扩展到测试微藻油提取，以验证表面活性剂辅助水相萃取方法和过程模型的通用性。本项目将研究支化表面活性剂与一种新型扩展表面活性剂(在表面活性分子的头部和尾部之间插入中间极性基团的表面活性剂)的混合物。延伸型表面活性剂与多种植物油的界面张力一直很低，但它们需要非常高的盐浓度才能达到最佳性能。通过将扩展表面活性剂与疏水和支化表面活性剂混合，所需的盐度将降低，而支化将减少表面活性剂的尾尾相互作用，从而允许更好的石油渗透率，从而提高萃取效率。这项创新研究的结果可能有益于社会，以及旨在增强俄克拉荷马大学本科生和研究生学习体验的教育倡议。表面活性剂在油籽提取中的新应用以及对这种方法的基础科学的理解将被整合到俄克拉荷马大学的胶体和表面科学课程中，该课程吸引了来自多个工程学科(即化学工程师、化学、环境工程和科学)的许多本科生和研究生。此外，本研究开发的基于表面活性剂的水基采油预测模型将提交给K-Gray Engineering Path数字图书馆，允许大学之间的课程共享。开发的模型将提供一个互动教学模块，学生可以在其中探索油籽提取的基本机理，以及在高级化学工艺设计中应用该模型。

CBET 1160053SabatiniThe vegetable oil extraction industry is the primary contributor of volatile organic compound emissions in the food industry. The annual hexane loss in the soybean oil extraction process alone in the US could be as high as 210 - 430 million liters. There are growing health concerns and increased environmental regulations regarding the use of hexane in vegetable oil extraction. Exposure to hexane at 15 ppm/day for three months has been shown to cause peripheral nerve damage, and hexane is also a potential hazardous explosive material. The U.S. Environmental Protection Agency (EPA) established regulations on hexane emission due to growing environmental concerns. There is a pressing need for more sustainable extraction method as an alternative to hexane. The overall goal of this research is to identify the fundamental processes that will allow us to develop a robust surfactant-based bio-oil extraction process, including a fundamentally-based model for design of microemulsion extraction processes for a range of bio-oils. The work proposed here would, for the first time, provide a quantitative understanding of fundamental processes influencing the bio-oil extraction by the aqueous surfactant-based method, and further would provide a new quantitative model which can be used for making a priori predictions of extraction performance under realistic conditions. The resulting model could be used to design surfactant-based extraction systems for a wide range of plants and oilseeds, which is not available at present. The results of this work have the potential to be transformative, in that they will significantly advance the way in which bio-oils are extracted, resulting in an industry-wide replacement of environmentally-hazardous solvent-based methods with more environmentally-benign aqueous surfactant-based methods. Aqueous processing of oilseed extraction is preferred over hexane because it is environmentally friendly, safe and produces oil with superior quality. While enzyme-based extraction of soybean oil can achieve greater than 90% oil extraction efficiency, the enzyme-assisted extraction process requires long incubation time, high temperature and produces stable emulsions, which are not desirable in industrial scale. To address these challenges, this project will utilize bio-compatible extended-surfactant systems to achieve high oil extraction efficiency while avoiding stable emulsion formation. The work will then be extended to test micro-algae oil extraction to validate the versatility of the surfactant-assisted aqueous extraction method and process model. This project will study the mixture of a branched surfactant with a novel extendedsurfactant (surfactants with an intermediate polarity groups inserted between the head and the tail of the surfactant molecule). Extended-surfactants consistently showed ultralow interfacial tension with a wide range of vegetable oils, but they require very high salt concentration to achieve optimum performance. By mixing extended-surfactants with a hydrophobic and branched surfactant, the requires salinity will be reduced while the branching will decrease the surfactant tail-tail interaction, allowing better oil penetration, thereby improving the extraction efficiency. The results of this innovative research potentially benefit to the society, as well as education initiatives designed to enhance the learning experience of undergraduate and graduate students at the University of Oklahoma. The new application of surfactant in oilseed extraction and understanding the fundamental science of this approach will be integrated into a colloids and surface science course at the University of Oklahoma, which has attracted a number of undergraduate and graduate students from multi engineering disciplines (i.e. chemical engineer, chemistry, environmental engineer and science). In addition, the developed aqueous surfactantbased oil extraction prediction model resulting from this research will be submitted to the K-Gray Engineering Pathway Digital Library, allowing course shareware among universities. The developed model will provide an interactive educational module where students can explore the fundamental mechanisms involved in oilseed extraction as well as applying the model in advanced chemical process design.