Collaborative Research: Novel Materials and Reactor Design for Coupled Electrolytic Hydrogen Production and Nitrate Removal with Resource Recovery from Drinking Water

研究机构：德克萨斯大学奥斯汀分校/爱荷华大学标题：合作研究：耦合电解制氢和硝酸盐去除与饮用水资源回收的新型材料和反应器设计硝酸盐是世界上最普遍存在的地下水污染物，其管理被美国国家工程院认为是重大挑战之一。催化处理已经成为饮用水中硝酸盐去除的一种更可持续的选择，但由于缺乏科学知识和新材料的创新，它的实施一直受到阻碍，这些新材料无法直接解决反应器性能和规模方面的挑战。具体来说，可伸缩反应器中的硝酸盐处理受到氢输送到活性催化剂位点的限制。PIs提出了一种高风险/高回报的方法，该方法基于通过电活性催化剂载体在原位产生吸附的原子氢。最重要的假设是，原子氢可以在发生硝酸盐还原的同一（或直接邻近）地点电解生成，并且这种生成可以与硝酸盐还原平衡，以消除氢的传质限制，优化氢的利用，最大限度地减少能源消耗，并回收增值资源铵和氯。提出的工作的具体目标是：1)确定负责合成具有高导电性，金属分散性，透水性和强度的碳基催化剂载体的基本大块材料和表面化学性质。2)阐明间歇式反应器和流式反应器中电解制氢和硝酸还原耦合过程的反应机理和动力学，并确定优化这些过程的新型催化材料的基本性质。3)评价离子交换-电化学混合反应器去除饮用水中硝酸盐的经济和环境可持续性。提出的方法包括新的合成和电/催化实验，旨在阐明结构/性质相关性，反应机制，以及有效去除硝酸盐和从模拟饮用水中回收氨的最佳反应器条件，并对该技术进行经济和环境生命周期分析，结合离子交换废盐水处理和再利用，将作为过程优化的反馈。提出的硝酸盐还原所需的氢气输送方法，消除了氢气到液体的传质限制，是创新的。潜在的科学进展包括：(i)基础见解和结构-活性关系，指导合成新的阴极材料，有效地产生氢和减少催化反应部位的硝酸盐；（ii）设计一种新型电解反应器，将这些坚固的阴极材料集成到填充床流系统中；（三）综合资源回收农业上有价值的铵，以及用于减轻催化剂污染和水消毒的氯；（四）发展和传播一种综合模式，以便扩大对新技术发展的成本和环境影响评估的规模。拟议的教育、外联和参与活动包括：(i)在pi实验室招募和教育少数民族和女性本科工程专业学生；（ii）为爱荷华州的研究生提供跨学科培训，旨在解决食物、能源和水（FEW）资源的可持续性问题；（iii）通过德州大学奥斯汀分校的工程开放日，让初中生和高中生接触到水处理的工程设计；（iv）开发新的教学模块，并通过行业合作伙伴向水务公司传播。

1706797 / 1705255PIs : Werth, Charles J. / Jawahar Hussaini, Syed Mubeen Institutions: University of Texas at Austin / University of IowaTitle: Collaborative Research: Novel Materials and Reactor Design for Coupled Electrolytic Hydrogen Production and Nitrate Removal With Resource Recovery from Drinking WaterNitrate is the world's most ubiquitous groundwater pollutant, and its management is recognized as one of the Grand Challenges by the National Academy of Engineering. Catalytic treatment has emerged as a more sustainable option for nitrate removal from drinking water, but its implementation has been stymied by a lack of scientific knowledge and innovation in new materials that directly address challenges in reactor performance and scale-up. Specifically, nitrate treatment in scalable reactors is limited by hydrogen delivery to reactive catalysts sites. The PIs propose a high risk/high reward approach that is based on generating adsorbed atomic hydrogen in situ via electroactive catalyst supports. The overriding hypothesis is that atomic hydrogen can be electrolytically generated at the same (or directly adjacent to) site where nitrate reduction occurs, and this generation can be balanced with nitrate reduction to eliminate hydrogen mass transfer limitations, optimize hydrogen use, minimize energy consumption, and recover value added resources ammonium and chlorine. The specific objectives of the proposed work are: 1) To identify the fundamental bulk material and surface chemical properties responsible for the synthesis of carbon-based catalyst supports with high- electrical conductivity, metal dispersion, water permeability, and strength. 2) To elucidate reaction mechanisms and kinetics of coupled electrolytic hydrogen generation and nitrate reduction processes in batch and flow-through reactors, and to identify the fundamental properties of new catalytic materials that optimize these processes. 3) To evaluate the economic and environmental sustainability of a hybrid ion exchange - electrochemical reactor for nitrate removal from drinking water.The proposed approach involves novel synthesis and electro/catalytic experiments that aim to elucidate structure/property correlations, reaction mechanisms, and optimal reactor conditions for efficient nitrate removal coupled with ammonia recovery from simulated drinking water, and an economic and environmental life cycle analyses of the technology coupled to ion exchange waste brine treatment and reuse that will serve as feedback for process optimization. The proposed approach for hydrogen delivery required for nitrate reduction that eliminates hydrogen gas to liquid mass transfer limitations is innovative. Potential scientific advancements include: (i) foundational insights and structure-activity relationships to guide synthesis of new cathodic materials that efficiently generate hydrogen and reduce nitrate at catalytically reactive sites; (ii) the design of a novel electrolytic- based reactor that integrates these robust cathodic materials into a packed-bed flow system; (iii) integrated resource recovery of agriculturally valuable ammonium, as well as chlorine for catalyst fouling mitigation and water disinfection; and (iv) the development and dissemination of an integrated model that allows scale up for a cost and environmental impact assessment for new technology development. Proposed educational, outreach and engagement activities include: (i) the recruitment and education of minority and women undergraduate engineering students in the laboratories of the PIs; (ii) interdisciplinary training of graduate students at Iowa in a program designed to address food, energy, and water (FEW) resource sustainability; (iii) the exposure of junior high and high school students to engineering design for water treatment through engineering open houses at UT Austin; and (iv) the development of a new teaching modules and dissemination to water utilities through an industry collaborator.