Acid-functionalized Nanoparticles for Hydrolysis of Lignocellulosic Biomass

[33538] [qh]考虑到石油的长期供应以及美国希望减少对外国石油的依赖，可再生燃料越来越多地被认为是石油基燃料的替代品。从多年生能源作物、农作物残渣和林业生物质中提取的纤维素乙醇可以取代目前美国石油消费的很大一部分。从纤维素中生产乙醇的挑战在于纤维素物质难以分解成糖。纤维素水解主要有两种方法：无机酸和酶。矿物酸的水解速度很快，但由于它们的腐蚀性，使用它们需要昂贵的材料，而且它们必须被分离再利用或中和并排放。酶比酸对葡萄糖的选择性更强，但价格昂贵且不能重复使用。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性核与提供强酸性和增强与木质纤维素生物质相互作用的配体结合来合成。该方法是合成磁铁矿纳米颗粒，并利用磁铁矿与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，但其他的可用作Brønsted酸位点。此外，配体将包含官能团（如芳香环），这将增强晶体纤维素和酸功能化纳米颗粒之间的相互作用。实验方案涵盖多方面，包括催化剂和水解后反应产物的表征，催化剂颗粒的可分离性和可重复使用性。Hohn和Wang将能够探测哪些催化剂性质，如酸位强度或羟基的存在对生物质生产葡萄糖很重要。这项研究的智力价值在于，它将是第一个研究酸功能化纳米颗粒水解的研究。它将产生木质纤维素水解的新知识，并将为未来在生物质转化中使用纳米技术的研究铺平道路。此外，葡萄糖是可从生物质中提取的糖的代表。然后，这些糖分子可以用作化学物质或燃料的平台分子，从而促进石油的替代。拟议的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在科学和工程领域招聘妇女的既定项目。

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.