An integrated technology for efficient selenium remediation

硒是一种金属，用于制造各种工业产品，包括玻璃、颜料、光伏电池和半导体器件。近年来，硒对地表水系统和地下水含水层的污染已经成为美国和世界范围内的一个严重问题。在天然水体中，硒主要以亚硒酸盐(SeO42-)和亚硒酸盐(SeO42-)的形式存在，这两种阴离子具有高度的溶解性和毒性。尽管硒(Se)具有抗氧化性，是人类健康必不可少的微量营养素，但由于有毒的Se氧离子在水生食物链中生物积累，长期暴露于过量Se会对生态系统健康造成不利影响，导致鱼类和水生无脊椎动物的突变和生殖障碍。该项目的总体目标是探索一种新的综合处理系统的设计、评估和优化，该系统可以从受污染的水中提取有毒的亚硒酸盐/亚硒酸根阴离子，并将它们还原为无毒和不可溶的元素硒(Se0)。为了推进这一目标，首席调查人员(PI)建议测试流动电极电容去离子(FCDI)离子分离过程与生物电化学系统(BES)在紧凑型反应器中的集成，以电为驱动力和电源来去除、减少和解毒受污染的废水中的亚硒酸盐/亚硒酸根阴离子。该项目的成功完成将使社会受益，因为它将产生新的基本知识和数据，以推动设计和部署更有效和更具成本效益的技术，在排放到接受水体之前从工业和受污染的废水流中去除Se。通过学生教育和培训将为社会带来更多好处，包括指导阿拉巴马大学的一名博士后研究员、一名研究生和一名本科生。传统的和商业上可用的水处理技术(如混凝/沉淀、离子交换和反渗透)不能同时从受污染的水中去除有毒的亚硒酸盐/亚硒酸根离子，并将它们转化为无毒和不可溶的零价硒(Se0)。在这个项目中，首席研究人员(PI)提出了一项假设，即将流动电极电容去离子(FCDI)离子分离过程与生物电化学系统(BES)集成到紧凑型反应器中，可以利用电力作为驱动力和能源，同时去除、还原有毒废水中的亚硒酸根，并将其转化为无毒的Se0。这项研究的具体目标是1)利用合成和真实世界的硒污染废水来表征、评估和优化一体化FCDI-BES反应器在相关操作条件下的性能；2)利用基因组测序来探索和揭示生物电化学还原亚硒酸盐/亚硒酸根阴离子的分子机理；以及3)进行生命周期分析(LCA)和全局敏感性分析，以指导拟议的新型一体化FCDI-BES处理系统的性能优化。为了落实这个项目的教育和培训目标，私人投资促进机构计划招募和指导本科生从事项目研究活动。此外，PIS建议利用阿拉巴马大学现有的项目来设计和提供两项年度教育活动，包括为来自阿拉巴马州黑带的120多所学校的30-50名高中生和教师进行身临其境的实验室演示。阿拉巴马州黑带是阿拉巴马州一个持续存在经济和社会挑战的地区，包括高贫困和高失业率。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Selenium is a metalloid that is utilized in the manufacturing of various industrial products including glasses, pigments, photovoltaic cells, and semiconductor devices. In recent years, the contamination of surface water systems and groundwater aquifers by selenium (Se) has become a critical problem in the United States and worldwide. In natural waters, Se predominantly exists as selenate (SeO42-) and selenite (SeO42-) oxyanion species which are both highly soluble and toxic. Although selenium (Se) is an essential micronutrient for human health due to its antioxidant properties, chronic exposure to excess Se can adversely impact ecosystem health causing mutations and reproductive impairments in fish and aquatic invertebrates as toxic Se oxyanions bioaccumulate in aquatic food chains. The overarching goal of this project is to explore the design, evaluation, and optimization of a new integrated treatment train that can extract toxic selenate/selenite oxyanions from contaminated water and reduce them to elemental selenium (Se0) which is non-toxic and non-soluble. To advance this goal, the Principal Investigators (PIs) propose to test the integration of a flow-electrode capacitive deionization (FCDI) ion separation process with a bioelectrochemical system (BES) into a compact reactor to remove, reduce, and detoxify selenate/selenite oxyanions from contaminated wastewater streams using electricity as driving force and power source. The successful completion of this project will benefit society through the generation of new fundamental knowledge and data to advance the design and deployment of more efficient and cost-effective technologies that could remove Se from industrial and contaminated wastewater streams prior to their discharge into receiving water bodies. Additional benefits to society will be achieved through student education and training including the mentoring of a post-doctoral research fellow, one graduate student, and one undergraduate student at the University of Alabama. Conventional and commercially available water treatment technologies (e.g., coagulation/precipitation, ion exchange, and reverse osmosis) cannot simultaneously remove toxic selenate/selenite oxyanions from contaminated water and convert them to non-toxic and insoluble zero valent selenium (Se0). In this project, the Principal Investigators (PIs) propose to test the hypothesis that the integration of a flow-electrode capacitive deionization (FCDI) ion separation process with a bioelectrochemical system (BES) into a compact reactor could enable the simultaneous removal, reduction, and conversion of toxic selenate/selenite oxyanions from contaminated wastewater to non-toxic Se0 using electricity as driving force and energy source. The specific objectives of the research are to 1) characterize, evaluate, and optimize the performance of the integrated FCDI-BES reactor under relevant operating conditions using synthetic and real-world selenium contaminated wastewater; 2) probe and unravel the molecular mechanisms of the bioelectrochemical reduction of selenate/selenite oxyanions using metagenomic sequencing; and 3) conduct a life cycle analysis (LCA) and a global sensitivity analysis to guide the optimization of the performance of the proposed new and integrated FCDI-BES treatment train. To implement the education and training goals of this project, the PIs plan to recruit and mentor undergraduate students to work on the project research activities. In addition, the PIs propose to leverage existing programs at the University of Alabama to design and deliver two annual educational activities consisting of immersive lab demonstrations for 30-50 high school students and teachers selected from over 120 schools located in the Alabama Black Belt, a region in the State of Alabama with persistent economic and social challenges including high poverty and high unemployment.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.