Acid-functionalized Nanoparticles for Hydrolysis of Lignocellulosic Biomass

1033538 Hohn随着对石油长期供应的担忧和减少美国对外国石油依赖的愿望，可再生燃料越来越多地被认为是石油基燃料的替代品。来自多年生能源作物、作物残渣和林业生物质的纤维素乙醇可以取代美国目前石油消费的很大一部分。从纤维素生产乙醇的挑战是难以将纤维素物质分解为糖。两种主要方法用于纤维素水解：无机酸和酶。无机酸具有快速的水解速率，但由于它们的腐蚀性，它们的使用需要昂贵的材料，并且它们必须被分离和重新使用或中和和排放。酶对葡萄糖的选择性比酸高，但价格昂贵，不能重复使用。堪萨斯州立大学化学工程系的首席研究员Hohn和Wang提出了一种用于木质纤维素材料预处理和水解的新型催化剂：酸功能化磁性纳米颗粒。他们的假设是，活性的、可分离的木质纤维素水解催化剂可以通过将磁芯与配体结合来合成，所述配体提供强酸性并增强与木质纤维素生物质的相互作用。该方法是合成磁铁矿纳米颗粒，并利用磁铁矿和酸官能团之间的强相互作用将配体结合到纳米颗粒上。这些配体将包含多个酸基团：一些与纳米颗粒结合，但其他可用作布朗斯台德酸位点。此外，配体将含有将增强结晶纤维素与酸官能化纳米颗粒之间的相互作用的官能团（如芳环）。实验计划涵盖了许多方面，包括催化剂和水解处理后的反应产物的表征，以及催化剂颗粒的可分离性和可重复使用性。Hohn和Wang将能够探索催化剂的哪些性质，如酸中心强度或羟基的存在对从生物质生产葡萄糖很重要。这项研究的智力价值在于，它将是第一个研究用于水解的酸官能化纳米颗粒的研究。这将产生新的知识，在木质纤维素水解，并将铺平道路，为未来的研究在生物质转化中使用纳米技术。此外，葡萄糖是可以从生物质衍生的糖的代表。然后，这些糖分子可以用作化学品或燃料的平台分子，从而促进石油的替代。拟议研究的更广泛影响是与开发将生物质转化为燃料的技术相关的社会利益，这可以减少美国对外国石油的依赖。此外，这项研究将被纳入一个实践讲习班，该讲习班将用于一个旨在加强科学和工程领域妇女招聘的既定方案。

1033538HohnWith concerns about the long-term supply of petroleum and the desire to decrease U.S. dependence on foreign oil, renewable fuels are increasingly being considered as replacements for petroleum-based fuels. Cellulosic ethanol from perennial energy crops, crop residue, and forestry biomass could replace a significant percentage of the current United States petroleum consumption. The challenge in producing ethanol from cellulose is the difficulty in breaking down cellulosic matter to sugars. Two primary methods are used for cellulose hydrolysis: mineral acids and enzymes. Mineral acids give fast hydrolysis rates, but their use requires expensive materials due to their corrosivity and they must be separated and reused or neutralized and discharged. Enzymes are more selective than acids towards glucose, but are expensive and cannot be reused.Principal Investigators Hohn and Wang of the Department of Chemical Engineering at Kansas State University propose a new type of catalyst for pretreatment and hydrolysis of lignocellulosic materials: acid-functionalized magnetic nanoparticles. Their hypothesis is that active, separable lignocellulose hydrolysis catalysts can be synthesized by combining a magnetic core with ligands that provide strong acidity and enhanced interaction with lignocellulosic biomass. The approach is to synthesize magnetite nanoparticles and utilize the strong interaction between magnetite and acid functionalities to bind ligands to the nanoparticle. These ligands will contain multiple acid groups: some that bind to the nanoparticle, but others that are available to act as Brønsted acid sites. In addition, the ligand will contain functional groups (like aromatic rings) that will enhance the interaction between crystalline cellulose and the acid-functionalized nanoparticles. The experimental plan covers many aspects, including characterization of the catalysts and the reaction products after hydrolysis treatments, and the separability and reusability of the catalyst particles.Hohn and Wang will be able to probe what catalyst properties such as acid site strength or the presence of hydroxyl groups are important for production of glucose from biomass. The intellectual merit of the proposed research is that it will be the first to investigate acid-functionalized nanoparticles for hydrolysis. It will generate new knowledge in lignocellulose hydrolysis, and will pave the way for future research in using nanotechnology in biomass conversion. In addition, glucose is a representative of sugars that can be derived from biomass. These sugar molecules then may be used as platform molecules for chemicals or fuels, thus serving to advance the replacement of petroleum. The broader impact of the proposed research is the benefit to society associated with developing technology to convert biomass to fuel that can decrease U.S. dependence on foreign oil. In addition, this research will be incorporated into a hands-on workshop that will be used in an established program designed to enhance recruitment of women in science and engineering.