EFRI E3P: Hydrogenolysis for upcycling of polyesters and mixed plastics

使用塑料对人类有巨大的好处；然而，塑料制品的使用寿命很长，造成了巨大的塑料废物积累。塑料升级回收涉及将塑料废物转化为具有高经济和环境价值的新材料。塑料升级回收工作的主要挑战之一是进料流的复杂性。塑料废物中的各种聚合物具有不同的分子结构，塑料废物通常含有大量的添加剂和污染物。允许处理混合塑料废物的方法可以降低与分类相关的成本，但这些方法将需要能够处理高度异质废物流的强大处理技术。这种过程的发展需要新的实验和计算工具来了解塑料废物的各种成分如何与用于驱动这种过程的催化剂相互作用。该项目结合了各种紧密耦合的实验和计算建模工具和方法，以探测复杂环境中塑料和催化剂之间的界面。研究人员还将探讨关键的塑料添加剂和污染物如何使界面化学复杂化，使用技术经济分析来确定降低升级回收成本和环境影响的最重要机会。该项目将为不同群体的学生提供塑料废物转化技术的跨学科培训。参与该项目的教师和学生将参与多种形式的外展活动，包括针对K-12学校儿童的面对面研讨会和针对终身学习者的电子资源开发。该项目的总体目标是开发允许同时或顺序处理混合塑料废物以获得理想单体的技术。要实现这一目标，需要了解聚合物解构是如何受到不同聚合物、单体、催化剂、气相以及塑料添加剂和污染物的影响的。提出的工作将确定如何操纵各种组分和相之间的相互作用，以实现有效的单一塑料组分和冷凝聚合物和聚烯烃的二元混合物的解构。催化氢解将被用作一种强大的技术来解构各种塑料，使用同时（一锅）和顺序的塑料混合物解聚。控制反应环境的方法将由具有天然聚合物解构、化学催化、先进原位表征、材料合成和表面改性以及计算专业知识的跨学科研究小组进行研究。该研究的变革方面在于关注多相反应工程，明确关注催化塑料解构的反应动力学和传质限制。实验验证的模型将与技术经济分析相结合，通过适当合成最佳催化剂、温度程序和反应器设计，设计将废塑料混合物转化为有价值单体的工艺。研究聚合物-催化剂界面的方法可以应用于氢解以外的领域，并将有助于解决与大分子与催化材料相互作用有关的基础科学问题。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Using plastics has tremendous benefits for humanity; however, the lifetime of plastic products is long, creating an enormous accumulation of plastic wastes. Upcycling of plastics involves transforming plastic waste into new materials with high economic and environmental value. One of the major challenges for plastics upcycling efforts is the complexity of the feed stream. The various polymers in plastic wastes have diverse molecular structures, and plastic wastes typically contain significant levels of additive and contaminants. Methods that allow processing of mixed plastic wastes can reduce costs associated with sorting, but these methods will require robust process technology capable of handling highly heterogeneous waste streams. Development of such processes requires new experimental and computational tools to understand how the various components of plastic wastes interact with the catalysts that are used to drive such processes. This project combines a variety of closely coupled, experimental and computational modeling tools and approaches to probe interfaces between plastics and catalysts in complex environments. The investigators will also address how key plastic additives and contaminants complicate the interfacial chemistry, using technoeconomic analysis to identify the most important opportunities for reducing upcycling cost and environmental impact. The project will lead to cross-disciplinary training of a diverse group of students in plastic waste conversion technology. Faculty and students on the project will engage in multiple forms of outreach, including both in-person workshops aimed at K-12 school children and development of electronic resources aimed at life-long learners. The overall goal of this project is to develop technologies that allow simultaneous or sequential processing of mixed plastic wastes to desirable monomers. Achieving this goal will require understanding how polymer deconstruction is influenced by different polymer, monomer, catalyst, and gas phases, as well as by the presence of plastics additives and contaminants. The proposed work will identify ways to manipulate the interactions between the various components and phases to achieve efficient deconstruction of single plastics components and binary mixtures of condensation polymers and polyolefins. Catalytic hydrogenolysis will be employed as a robust technique for deconstruction of diverse plastics, using both simultaneous (one-pot) and sequential depolymerization of plastic mixtures. Methods for controlling the reaction environment will be investigated by an interdisciplinary team of researchers with expertise in natural polymers deconstruction, chemical catalysis, advanced in situ characterization, materials synthesis and surface modification, and computation. The transformative aspect of the research lies in the focus on multiphase reaction engineering, with an explicit focus on both reaction kinetics and mass transfer limitations in catalytic plastics deconstruction. Experimentally validated models will be used in conjunction with techno-economic analysis to design processes that convert mixtures of waste plastics to valuable monomers through appropriate synthesis of optimal catalysts, temperature programs, and reactor designs. The methods for studying polymer-catalyst interfaces can be applied beyond the hydrogenolysis and will be useful in addressing fundamental science problems related to the interaction of macromolecules with catalytic materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.