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

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，能够释放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给最终产品增加了巨大的成本，并在藻类和生物燃料之间形成了一个主要障碍。在微藻脱水的基本原理方面存在知识空白，特别是对于混凝剂的合理设计。这项工作的长期目标是了解控制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漂浮细胞的相分离。该提案的总体目标是确定藻对间相互作用和混凝剂结构之间的合理相关性，以便以可忽略的成本实现高效的微藻脱水。中心假设是纳米颗粒捏聚合物刷，即，共价键合到纳米颗粒核上的辐射状聚合物链在使微藻脱水方面比常规絮凝剂有效得多;此外，使用固态纳米颗粒允许低成本操作（例如，使用磁场）被设计成收集藻类生物质并回收用于多个循环的微藻脱水的凝结剂，这进一步显著降低了操作成本。我们已经制定了这一假设的基础上，我们强烈支持的初步数据。所提出的研究的基本原理是，一旦理解了这种新型混凝剂的异常高性能的结构特征，预计对其结构的精确控制将使微藻脱水具有前所未有的成本效益。因此，阻碍微藻生物燃料商业化的瓶颈将被清除。我们计划通过追求以下三个具体目标来测试我们的中心假设并实现本申请的总体目标：1.确定一种简便高效的方法来合成具有明确结构的顺磁性纳米颗粒捏聚合物刷; 2.确定混凝剂的结构特征对微藻脱水效率的调控作用; 3.确定回收纳米颗粒捏聚合物刷的效率，用于微藻生长和脱水的连续循环。这项工作的预期贡献是确定工程混凝剂的结构特征，赋予它们在微藻脱水中具有异常高的效率和异常低的运营成本。这一贡献是显著的，因为它通过检查藻类间的相互作用和明确定义的结构的絮凝剂之间的合理相关性来创建一类超级絮凝剂。尽管对商业上可获得的化学品进行了数十年的不懈试错实验，但这方面的理解仍然很少。能源和环境是我们社会可持续发展的最大挑战。众所周知，确保可再生能源是我们这个时代的重大挑战，但并不总是认识到，为解决这一挑战而提出的任何工程材料本身必须是可持续的，一个例子是微藻混凝剂的设计。研究人员计划通过以下综合活动在这方面引起广泛的社会认识：将研究纳入教学。组建的研究团队将成为一个核心，通过举办研讨会，开发课程材料和吸引行业赞助来加强矿山的生物燃料研究。PI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传播到Youtube，为可持续能源的可持续材料做广告;与代表性不足的群体进行外联。研究人员计划通过开发有关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的可持续推广计划，PI和他的研究生将使用该计划，以参与矿山现有的推广计划，该计划跨越两个学区的幼儿园年级，亚当斯县50区（AC 50）和米克县（MC）。这两个学区都位于农村，生活贫困的学生比例很高

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