Collaborative Research: High Surface Area Mesoporous Carbons for Facile Biofuel Recovery from Dilute Aqueous Solution

1159295/1159200Vogt/Nielsen尽管在利用可再生生物质资源生产可持续液体运输燃料方面取得了重大进展，但在大多数传统生物工艺中，最终产品毒性仍然是一个关键的生产率限制因素。减轻生物燃料产品毒性的一种有效方法是从培养物中就地回收生物燃料，这需要低成本、低能源和生物兼容的分离技术，选择性地从稀水溶液中去除生物燃料。低能分离过程已被提出，但大多数先前的研究都集中在模型生物燃料-水溶液上；实际过程受到复杂生物混合物的挑战，容易造成污垢和较差的材料生物相容性，从而对分离性能和整个过程的可行性产生不利影响。在这里，我们建议系统地研究磁性、介孔、碳基材料，以阐明在理想溶液和生长培养条件下，基本物理化学性质如何影响生物燃料(乙醇和正丁醇)回收的吸附剂性能。生物燃料-吸附剂相互作用的基本和机理特征，以及非理想相互作用(污垢现象)，将提供真实系统的结构-功能关系。最终，将通过将这些材料与生产生物燃料的微生物培养相结合来评估通过连续、就地回收生物燃料而实现的生产率提高。有序介孔材料的高比表面积和孔可及性使其在生物燃料分离方面具有很大的吸引力。我们建议使用软模板化介孔碳作为生物燃料吸附剂；对孔大小、比表面积和孔形态的综合调节将提供对这些性质如何影响生物燃料吸附容量、分配系数和吸附热的基本理解。我们提出了一种单罐合成方法，在不显著影响介观结构的情况下将钴纳米颗粒包含在碳中，从而实现了吸附剂与培养物的磁分离。将对回收效果进行系统检查，以确定磁选是否是吸附剂回收的可行机制。我们将从基础研究开始，使用模型解决方案与其他常用的生物燃料分离吸附剂进行直接比较；然而，在实际应用中，额外的考虑将是至关重要的。事实上，生产生物燃料的培养物是复杂的混合物，其中的污垢和其他非理想的相互作用会导致分离性能的改变。同时，介孔碳的微生物生物相容性相对较差。因此，我们将系统地研究非理想相互作用的性质和程度，以定义和纳入在现实工艺条件下促进持续性能的材料特性。将开发和研究两种不同的回收策略以进行比较分析：传统的外循环填充床柱，以及磁性吸附颗粒在整个培养过程中的新型分散(随后进行磁性收集)。我们预计，后一种从未在生长中、生产生物燃料的培养中被检验过的新方法将提供更高的效率，因为它使吸附剂和培养介质之间能够持续接触，而不需要昂贵和破坏细胞的泵送。这项端到端的概念验证研究将能够评估吸附剂的物理性能如何影响从生长中的微生物培养物中连续、就地去除乙醇和正丁醇的性能。这些顶峰实验独一无二地允许直接评估在理想化条件下执行的基本特征是否以及如何预测真实系统的性能。从根本上了解用于吸附生物燃料的介孔材料的性质-结构关系将使生物燃料从培养液中更有效地分离出来，并将有助于减少美国对外国化石燃料的依赖。更广泛的教育影响将涉及研究生和本科生参与这一高度跨学科的调查领域。此外，这项研究的概念和结果将被纳入一个关于生物反应器和生物燃料的新的教学实验模块。提议向代表人数不足的当地K-12学生开展外联活动，以讨论生物燃料的社会重要性及其分离和生产所带来的挑战；此外，这些活动将旨在纠正对纳米技术的普遍误解。将通过阿克伦全球聚合物学院向P-16进行更广泛的传播，该学院覆盖全球。

1159295/1159200Vogt/NielsenDespite significant developments in producing sustainable liquid transportation fuels from renewable biomass resources, end-product toxicity remains a key, productivity-limiting factor in most conventional bioprocesses. One effective approach to relieve biofuel product toxicity is through its in situ recovery from the culture, which requires low cost, low energy, and biocompatible separation technologies that selectively remove biofuels from dilute aqueous solutions. Low energy separation processes have been proposed, but most prior studies have focused on model, biofuel-water solutions; real processes are challenged by complex biological mixtures prone to cause fouling and poor material biocompatibility, which adversely impact separation performance and overall process viability. Here, we propose to systematically examine magnetic, mesoporous, carbon-based materials to elucidate how fundamental physicochemical properties impact adsorbent performance for biofuel (ethanol and n-butanol) recovery in both idealized solutions and growing cultures. Fundamental and mechanistic characterizations of biofuel-adsorbent interactions, as well as nonideal interactions (fouling phenomena), will provide structure-function relationships in real systems. Ultimately, the productivity enhancements that can be realized through continuous, in situ biofuel recovery will be assessed by integrating these materials with biofuel-producing microbial cultures. High surface area and pore accessibility of ordered mesoporous materials make them attractive for biofuel separations. We propose to utilize soft templated mesoporous carbons as biofuel adsorbents; synthetic tuning of the pore size, surface area, and pore morphology will provide a fundamental understanding of how these properties impact biofuel adsorption capacity, partition coefficients, and heats of adsorption. We propose a single pot synthesis to include cobalt nanoparticles in the carbon without significantly impacting the mesostructure to enable magnetic separation of the adsorbent from culture. Recovery efficacy will be systematically examined to determine if magnetic separation is a viable mechanism for adsorbent recovery. We will begin with fundamental studies using model solutions for direct comparison with other commonly examined adsorbents for biofuel separations; however, additional considerations will be critical in real applications. In reality, biofuel-producing cultures are complex mixtures wherein fouling and other non-ideal interactions lead to altered separation performance. Meanwhile, the microbial biocompatibility of mesoporous carbons is relatively unknown. Accordingly, we will systematically examine the nature and degree of non-ideal interactions to define and incorporate material properties promoting sustained performance under realistic process conditions. Two different recovery strategies will be developed and examined for comparative analysis: a traditional, externally circulated packed-bed column, and the novel dispersion of magnetic adsorbent particles throughout the culture (followed by their magnetic collection). We anticipate the latter novel approach, which has never been examined in growing, biofuel-producing cultures, will provide improved efficacy as it enables continuous contact between the adsorbent and culture medium without costly and cell-damaging pumping requirements. This end-to-end, this proof-of-concept study will enable evaluation of how adsorbent physical properties impact performance as applied to continuous, in situ removal of ethanol and n-butanol from growing microbial cultures. These capstone experiments uniquely allow direct evaluation of if and how fundamental characterizations performed under idealized conditions can predict performance in real systems. A fundamental understanding of the property-structure relationships of mesoporous materials for biofuel adsorption would enable more efficient separations of biofuels from culture broths and will aid in reducing the U.S. dependence on foreign fossil fuels. The broader educational impact will involve participation of graduate and undergraduate students in this highly interdisciplinary area of inquiry. Moreover, concepts and results from this research will be incorporated into a new teaching lab module on bioreactors and biofuels. Outreach activities to local underrepresented K-12 students are proposed to discuss the societal importance biofuels and the challenges associated with their separation and production; additionally, these activities will aim to correct common misconceptions regarding nanotechnology. Broader dissemination to P-16 will be enabled through the Akron Global Polymer Academy, which has worldwide reach.