Collaborative Research: Mechanistic study of mesoporous carbon formation from food waste

在美国，超过三分之一的食物被浪费了。大约94%的这些浪费的食物最终进入垃圾填埋场，焚化炉和城市污水系统。在垃圾填埋场，食物垃圾的分解会产生温室气体（甲烷和二氧化碳）和其他副产品，可能导致土壤，空气和水污染。由于食物垃圾是可支持循环经济的有机碳的可再生来源，因此迫切需要将食物垃圾转化为高价值产品的新颖且具有成本效益的工艺。该项目的总体目标是探索将无骨/均质化食物垃圾转化为介孔碳，可用于制造超级电容器和储能应用的电极。为了推进这一目标，主要研究者（PI）建议设计，评估，并优化了一种新的两阶段工艺，该工艺由表面活性剂辅助的食物垃圾水热碳化（HTC）以产生水热炭前体材料，随后热处理以产生用于制备具有高比表面积的超级电容器的电极级中孔碳材料组成（2000 m2/g）和电容（275/F/g）。该项目的成功完成将通过产生新的数据和基础知识来促进食物垃圾转化为用于超级电容器和储能应用的介孔碳，从而造福社会。通过学生教育和培训，包括指导Old自治领大学的一名研究生和南达科他州矿业与技术学院的一名研究生，将为社会带来额外的好处。食物垃圾是推进循环经济的一种有前途的资源和原料。然而，存在与将食物垃圾加工和转化为有价值的有机化合物相关的若干挑战，包括其高水分含量、可变成分和无机杂质的存在。水热碳化（HTC），可以利用水作为反应介质，已成为一种有前途的方法，将食物垃圾转化为高价值的有机产品。在这个项目中，主要研究人员（PI）将探索利用表面活性剂辅助HTC将均质化和无骨的食物垃圾转化为水热炭，然后对所产生的水热炭进行热处理，以产生用于超级电容器和储能应用的电极级中孔碳。所提出的研究的指导假设是：1）表面活性剂胶束在水热介质中的自组装将为在食物垃圾的HTC期间形成的分散的水热炭提供成核和生长位点，以及2）表面活性剂的使用将在热处理期间打开水热炭的孔以改善中孔性、比表面积和离子嵌入。本研究的具体目标是：1）对表面活性剂辅助热裂解过程中水热炭的形成机理进行研究; 2）开发和验证水热炭中金属杂质的去除方法; 3）研究合成和纯化的水热炭的化学热处理以生成介孔碳;以及4）进行生命周期评估（LCA）和技术经济分析（TEA），以评估从食物垃圾生产用于超级电容器制造和能量存储应用的中孔碳的环境影响和经济可行性。为了实现该项目的教育和培训目标，PI建议利用旧自治领大学（ODU）和南达科他州矿业与技术学院（SDSMT）的现有项目，1）招募和指导来自代表性不足群体的研究生和本科生从事该项目，2）开发和实施推广活动，以促进多样性，公平，该奖项反映了NSF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。

Over one-third of the food produced in the United States goes to waste. About 94% of this wasted food ends up in landfills, incinerators, and municipal sewage systems. In landfills, the decomposition of food waste generates greenhouse gases (methane and carbon dioxide) and other by-products that can cause soil, air, and water pollution. Because food waste is a renewable source of organic carbon that can support a circular economy, there is a critical need for novel and cost-effective processes for converting food waste to high value products. The overarching goal of this project is to explore the conversion of boneless/ homogenized food waste into mesoporous carbon which could be used to fabricate electrodes for supercapacitors and energy storage applications. To advance this goal, the Principal Investigators (PIs) propose to design, evaluate, and optimize a novel 2-stage process which consists of a surfactant assisted hydrothermal carbonization (HTC) of food waste to produce a hydrochar precursor material followed thermal treatment to produce an electrode-grade mesoporous carbon material for preparing supercapacitors with high specific surface area (2000 m2/g) and electrical capacitance (275/F/g). The successful completion of this project will benefit society through the generation of new data and fundamental knowledge to advance the conversion of food waste to mesoporous carbon for supercapacitors and energy storage applications. Additional benefits to society will be achieved through student education and training including the mentoring of one graduate student at Old Dominion University and one graduate student at the South Dakota School of Mines and Technology.Food waste is a promising resource and feedstock for advancing a circular economy. However, there are several challenges associated with the processing and conversion of food waste to valuable organic compounds including its high moisture content, variable composition, and the presence of inorganic impurities. Hydrothermal carbonization (HTC), which can utilize water as a reaction medium, has emerged as promising process for the conversion of food waste to high-value organic products. In this project, the Principal Investigators (PIs) will explore the ulization of surfactant assisted HTC to convert homogenized and boneless food waste to hydrochar followed by the thermal treatment of the produced hydrochar to generate an electrode-grade mesoporous carbon for supercapacitors and energy storage applications. The guiding hypotheses of the proposed research are that 1) the self-assembly of surfactant micelles in hydrothermal media will provide nucleation and growth sites for the dispersed hydrochar that forms during the HTC of food waste and 2) the use of a surfactant will open the pores of the hydrochar during thermal treatment to improve mesoporosity, specific surface area, and ion intercalation. The specific objectives of the research are to 1) conduct mechanistic investigations of hydrochar formation during surfactant assisted HTC; 2) develop and validate treatment processes to remove metallic impurities from hydrochar; 3) investigate the chemical-thermal treatment of the synthesized and purified hydrochar to generate mesoporous carbon; and 4) carry out a life cycle assessment (LCA) and techno-economic analysis (TEA) to evaluate the environmental impact and economic feasibility of producing mesoporous carbon from food waste for supercapacitor manufacturing and energy storage applications. To implement the education and training goals of the project, the PIs propose to leverage existing programs at Old Dominion University (ODU) and the South Dakota School of Mines and Technology (SDSMT) to 1) recruit and mentor graduate and undergraduate students from underrepresented groups to work on the project and 2) develop and implement outreach activities to advance diversity, equity, and inclusion in STEM education including annual workshops at ODU and SDSMT that focus on the science and engineering of food waste conversion to high value products.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.