Retrievable and Reusable Nanoparticle-Pinched Polymer Brushes Enable Highly Efficient Microalgae Dewatering for Cost-Effective Biofuel Production

1160291梁基于生产率和环境考虑的各种分析表明，来自微藻的生物燃料可能是唯一现实的替代品，能够减轻我们对化石燃料的依赖。尽管经过几十年的努力，微藻衍生生物燃料的商业化生产尚未出现，因为目前的微藻脱水技术增加了最终产品的巨大成本，并成为藻类养殖和生物燃料之间的主要障碍。关于微藻脱水的基本原理，尤其是凝固剂的合理设计，存在着知识空白。这项拟议工作的长期目标是了解支配活细胞胶体悬浮液稳定性的基本原理，并以可控的方式指导自由浮动细胞的相分离。这项建议的总体目标是确定藻间相互作用和凝固剂结构之间的合理相关性，以便以微不足道的成本实现高效的微藻脱水。中心假设是，纳米颗粒夹持的聚合物刷子，即辐射共价键合到纳米颗粒核心的聚合物链，在脱水微藻方面比传统的絮凝剂有效得多；此外，使用固态纳米颗粒允许低成本的操作(例如，使用磁场)设计为收集藻类生物量并回收凝固剂进行多次微藻脱水，这进一步显著降低了运营成本。我们根据我们强有力的初步数据提出了这一假设。这项拟议研究的基本原理是，一旦了解了导致这种新型凝固剂异常高性能的结构特征，对其结构的精确控制有望实现前所未有的成本效益微藻脱水。因此，阻碍微藻衍生生物燃料商业化的瓶颈将被清除。我们计划验证我们的中心假设，并通过追求以下三个具体目标来实现这一应用的总体目标：1.找到一种简便和高效的方法来合成结构明确的顺磁性纳米颗粒捏合聚合物刷子；2.确定微藻脱水效率如何受到凝固剂结构特征的调节；3.确定回收纳米颗粒捏合聚合物刷子用于微藻生长和脱水的连续循环的效率。这项工作的预期贡献是确定工程凝固剂的结构特征，使其在微藻脱水中具有异常高的效率和异常低的运行成本。这一贡献意义重大，因为它通过检查藻间相互作用和结构明确的絮凝剂之间的合理相关性，创造了一类超级凝血剂。尽管几十年来用商业上可获得的化学品进行了无情的反复试验，但人们对这方面的了解很少。能源和环境是我们社会可持续发展面临的最大挑战。众所周知，确保可再生能源是我们这个时代的重大挑战，但人们并不总是认识到，为应对这一挑战而提出的任何工程材料本身必须是可持续的，这一应用中的微藻凝固剂的设计就是一个例子。研究人员计划通过以下综合活动提高社会对这方面的广泛认识：将研究纳入教学。组建的研究团队将通过举办研讨会、开发课程材料和吸引行业赞助，成为加强Mines生物燃料研究的核心。国际和平协会将建立一个专门讨论微藻收获问题的网页，并将微藻脱水实验的视频剪辑发布到YouTube上，宣传可持续能源的可持续材料；向代表不足的群体宣传。研究人员计划通过开发关于藻类生物燃料的讲座材料和课堂演示实验来建立一个有针对性和可持续的扩展计划，PI和他的研究生将使用这些材料来参与Mines现有的扩展计划，该计划跨越两个学区-亚当斯县第50区(AC50)和米克县(MC)-从幼儿园到第十二年级。这两个学区都位于农村，贫困学生的比例很高。

1160291LiangVarious analyses based on the production rate and environmental considerations have suggested that biofuels from microalgae are likely the only realistic substitute capable of releasing our reliance on fossil fuels. Despite decades of effort, commercial production of microalgae-derived biofuels has not emerged because current technologies for microalgae dewatering add a huge cost to the final product, and present a major barrier between algaculture and biofuels. A knowledge gap exists in the underlying principles governing microalgae dewatering, particularly for the rational design of coagulation agents. The long-term goal of the proposed work is to understand the underlying principles that govern the stability of a colloidal suspension of living cells, and to direct the phase separation of free-floating cells in a controllable fashion. The overall objective of this proposal is to identify the rational correlations between inter-algal pair interactions and coagulation-agent structures in order to achieve highly efficient microalgae dewatering at a negligible cost. The central hypothesis is that nanoparticle-pinched polymer brushes, i.e., radiating polymer chains covalently bonded to a nanoparticulate core, are far more effective in dewatering microalgae than conventional flocculants; in addition, using solid-state nanoparticles allows low-cost operations (e.g., using magnetic fields) to be designed to collect algal biomass and retrieve the coagulation agents for multiple cycles of microalgae dewatering, which further reduces the operational cost significantly. We have formulated this hypothesis based on our strongly supportive preliminary data. The rationale underlying the proposed research is that, once the structural characteristics responsible for the unusually high performance of this novel coagulation agent are understood, precise control of its structure is expected to enable unprecedentedly cost-effective microalgae dewatering. Hence the bottleneck preventing commercialization of microalgae-derived biofuels will be cleared. We plan to test our central hypothesis and accomplish the overall objective of this application by pursuing the following three specific aims: 1. Identify a facile and highly efficient approach to synthesize paramagnetic nanoparticle-pinched polymer brushes with well-defined structures; 2. Determine how the microalgae dewatering efficiency is regulated by the structural characteristics of the coagulation agents; 3. Determine the efficiency of retrieving nanoparticle-pinched polymer brushes for continuous cycles of microalgae growth and dewatering. The expected contribution of this work is to determine the structural characteristics of engineered coagulation agents that endow them with an unusually high efficiency in microalgae dewatering and an unusually low operational cost. This contribution is significant, because it creates a class of super coagulation agents via examining rational correlations between inter-algal pair interactions and flocculants of well-defined structures. This aspect has been poorly understood despite decades of relentless trial-and-error experiments with commercially available chemicals. Energy and environment represent the top challenges for the sustainable development of our societies. It is well understood that securing renewable energy sources is the grand challenge of our time, but it is not always recognized that any engineered material proposed to address that challenge must be sustainable itself, an example is the design of microalgae coagulation agent in this application. The researchers plan to bring broad societal awareness on this aspect with the following integrated activities: Incorporating research into teaching. The assembled research team will be a nucleus to enhance biofuel research at Mines by giving seminars, developing course materials, and attracting industry sponsorship. The PI will build a webpage devoted to microalgae harvesting issues, and disseminate the video clips of microalgae dewatering experiments to Youtube to advertise sustainable materials for sustainable energy; Outreach to Underrepresented Groups. The researchers plan to build a focused and sustainable outreach program by developing lecture materials and classroom demonstration experiments on algal biofuels, which will be used by the PI and his graduate students, to participate in an existing outreach program at Mines that spans grades kindergarten through the twelfth in two school districts, Adams County District 50 (AC50) and Meeker County (MC). Both school districts are rurally located and have a high proportion of students who are living in poverty