An integrated technology for efficient selenium remediation

硒是一种准金属，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（Se）对地表水系统和地下水含水层的污染已成为美国和世界范围内的一个关键问题。 在天然沃茨中，硒主要以硒酸盐（SeO 42-）和亚硒酸盐（SeO 42-）的形式存在，它们都是高溶解性和毒性的。虽然硒（Se）由于其抗氧化特性而对人类健康是必需的微量营养素，但长期暴露于过量的Se会对生态系统健康产生不利影响，导致鱼类和水生无脊椎动物的突变和生殖障碍，因为有毒的Se含氧阴离子在水生食物链中生物积累。该项目的总体目标是探索一种新的综合处理列车的设计、评估和优化，该列车可以从受污染的水中提取有毒的硒酸盐/亚硒酸盐含氧阴离子，并将其还原为无毒且不溶的元素硒（Se 0）。为了推进这一目标，主要研究人员（PI）建议测试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）集成到一个紧凑的反应器中，以使用电力作为驱动力和电源从受污染的废水流中去除，减少和解毒硒酸盐/亚硒酸盐含氧阴离子。该项目的成功完成将通过产生新的基础知识和数据来促进设计和部署更有效和更具成本效益的技术，从而使社会受益，这些技术可以在工业和受污染的废水流排放到接收水体之前将其去除。通过学生教育和培训，包括指导亚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，将为社会带来更多好处。传统的和商业上可获得的水处理技术（例如，凝聚/沉淀、离子交换和反渗透）不能同时从污染的水中去除有毒的硒酸盐/亚硒酸盐含氧阴离子并将它们转化为无毒和不溶性的零价硒（Se 0）。在这个项目中，主要研究人员（PI）提出测试的假设，即集成的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）到一个紧凑的反应器，可以使同时去除，减少和转换有毒的硒酸盐/亚硒酸盐含氧阴离子从污染的废水无毒的Se 0使用电力作为驱动力和能源。本研究的具体目标是：1）在相关操作条件下，以人工合成和实际硒污染废水为研究对象，对FCDI-BES一体化反应器的性能进行表征、评价和优化; 2）利用宏基因组测序技术，探索和揭示硒酸盐/亚硒酸盐含氧阴离子生物电化学还原的分子机制; 3）进行生命周期分析（LCA）和全局灵敏度分析，以指导所提出的新的和集成的FCDI-BES处理列的性能的优化。为落实本计划的教育及培训目标，研究院计划招募及指导本科生参与本计划的研究活动。此外，PI建议利用亚拉巴马大学的现有项目，设计和提供两项年度教育活动，包括为从位于亚拉巴马黑带的120多所学校中选出的30-50名高中学生和教师进行沉浸式实验室演示，该地区位于亚拉巴马州，面临持续的经济和社会挑战，包括高贫困和高失业率。该奖项反映了NSF的基金会的使命是履行其法定使命，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。

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.