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

1706797 /1705255 PI：Werth，Charles J. / Jawahar Hussaini，Syed Mubeen机构：德克萨斯大学奥斯汀分校/爱荷华大学标题：合作研究：新型材料和反应器设计用于耦合电解制氢和硝酸盐去除与饮用水资源回收硝酸盐是世界上最普遍的地下水污染物，它的管理被美国国家工程院认为是重大挑战之一。催化处理已成为饮用水中硝酸盐去除的一种更可持续的选择，但由于缺乏直接应对反应器性能和规模扩大挑战的新材料的科学知识和创新，其实施受到阻碍。具体地，在可扩展的反应器中的硝酸盐处理受限于向反应性催化剂位点的氢气输送。PI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原位产生吸附的原子氢。最重要的假设是，原子氢可以在硝酸盐还原发生的相同（或直接相邻）地点电解产生，并且这种产生可以与硝酸盐还原平衡，以消除氢传质限制，优化氢的使用，最小化能量消耗，并回收增值资源铵和氯。所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、水渗透性和强度的碳基催化剂载体的基本本体材料和表面化学性质。2)阐明间歇式和流通式反应器中耦合电解制氢和硝酸盐还原过程的反应机理和动力学，并确定优化这些过程的新催化材料的基本性质。3)为评价离子交换-电化学复合反应器去除饮用水中硝酸盐的经济性和环境可持续性，提出的方法包括新的合成和电/催化实验，旨在阐明结构/性能相关性，反应机理和最佳反应器条件，以有效去除硝酸盐并从模拟饮用水中回收氨。并对离子交换废盐水处理和再利用技术进行了经济和环境生命周期分析，作为工艺优化的反馈。所提出的用于硝酸盐还原所需的氢气输送的方法是创新的，其消除了氢气到液体的传质限制。潜在的科学进步包括：（i）指导新阴极材料合成的基础见解和结构-活性关系，所述新阴极材料在催化反应位点有效地产生氢气和还原硝酸盐;（ii）设计新型基于电解质的反应器，其将这些稳健的阴极材料整合到填充床流动系统中;（iii）对农业上有价值的铵以及氯进行综合资源回收，以减轻催化剂结垢和水消毒;以及（四）开发和推广一个综合模型，以便扩大新技术开发的成本和环境影响评估。 拟议的教育、外联和参与活动包括：㈠在公共工程学院的实验室招募和教育少数族裔和妇女工程专业本科生; ㈡在爱荷华州开展旨在解决粮食、能源和水资源可持续性问题的方案，对研究生进行跨学科培训;（iii）透过UT Austin的工程开放日，让初中及高中学生接触水处理工程设计;及（iv）发展新的教学模式，并透过业界合作伙伴向水务公司推广。

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.