Nano- and Macroscale Physico-chemical Processes Impacting Arsenic Mobilization

影响砷迁移的纳米和宏观物理化学过程

• 批准号: 1424927
• 负责人: Young-Shin Jun
• 金额: $ 34.06万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1424927&HistoricalAwards=false
• 关键词: Nano; Macroscale; Physico; chemical; Processes

Managed aquifer recharge (MAR) is one water reuse technique with the potential to meet growing water demands. In MAR, reclaimed wastewater is injected into aquifer formations for later use. Although filtration and adsorption in the vadose zone and underlying aquifer can remove some contaminants from reclaimed water, unfavorable soil-water interactions can mobilize arsenic from arsenic-bearing aquifer formations. This work will investigate how the interactions between water and arsenic-bearing pyrite, such as arsenopyrite/arsenian pyrite, impact arsenic mobility during MAR, and investigators will provide new quantitative and qualitative fundamental information on the redox-promoted dissolution mechanisms of arsenic-bearing pyrite and the consequent nucleation, growth, and phase transformation of iron (hydr)oxide nanoparticles, which are closely linked with arsenic mobilization and attenuation. By combining novel multidisciplinary approaches and in situ observations, including atomic force microscopy using an electrochemical control, small angle X-ray scattering, and batch reactor experimental measurements, they will obtain quantitative parameters and clearer qualitative descriptions of the thermodynamics and kinetics of initial iron (hydr)oxide nuclei evolution at the mineral-water interface. For the first time, new information on nucleation will be incorporated into geochemical reactive transport models to improve the prediction accuracy. The experimental results will also be compared with available data from pilot-scale column experiments at the U.S. EPA's Test & Evaluation Facility in Cincinnati, OH, and from MAR field sites. The results will help determine pretreatment requirements for reclaimed water sources and will provide a basis for developing more sustainable MAR operation guidelines. Beyond this application, the knowledge gained can be applied to related geochemical systems, including regions struggling with pervasive arsenic contamination of groundwater and environments where quantification of arsenic sorption onto nanoscale iron (hydr)oxide precipitates is a source of great uncertainty. The proposed outreach plan will provide educational, research, public engagement, and professional development opportunities for middle school, high school, undergraduate, and graduate students. It will have far-reaching societal impacts. In addition, the participation of traditionally underrepresented students will be encouraged. To achieve this goal, investigators will develop a "Hot Topics" website and related workshops focused on water quality concepts, in collaboration with Washington University's Institute for School Partnership and teachers from St. Louis' middle and high schools. To encourage high school and undergraduate students' early involvement in science and engineering, they will provide scientific research projects and offer public lectures on water quality.

含水层管理补给（MAR）是一种有潜力满足日益增长的用水需求的水再利用技术。在MAR中，回收的废水被注入含水层供以后使用。虽然渗透带和下伏含水层的过滤和吸附可以去除再生水中的一些污染物，但不利的土壤-水相互作用可以从含砷含水层中调动砷。这项工作将研究水与含砷黄铁矿（如毒砂/含砷黄铁矿）之间的相互作用如何影响MAR期间砷的迁移，研究人员将为氧化还原促进含砷黄铁矿的溶解机制以及与砷的动员和衰减密切相关的铁（氢）氧化物纳米颗粒的成核、生长和相变提供新的定量和定性基础信息。通过结合新的多学科方法和现场观察，包括使用电化学控制的原子力显微镜，小角度x射线散射和间歇反应器实验测量，他们将获得定量参数和更清晰的定性描述，即矿物质-水界面初始铁（水）氧化物核演化的热力学和动力学。首次将成核的新信息纳入地球化学反应输运模型，以提高预测精度。实验结果还将与位于俄亥俄州辛辛那提市的美国环保署测试和评估设施的中试规模柱实验数据和MAR现场数据进行比较。研究结果将有助于确定再生水源的预处理要求，并将为制定更可持续的MAR操作准则提供基础。除了这一应用之外，所获得的知识还可以应用于相关的地球化学系统，包括与地下水普遍存在砷污染作斗争的地区，以及砷在纳米级铁（水合）氧化物沉淀物上吸附的量化存在很大不确定性的环境。拟议的外展计划将为初中生、高中生、本科生和研究生提供教育、研究、公众参与和专业发展机会。它将产生深远的社会影响。此外，将鼓励传统上代表性不足的学生参与。为了实现这一目标，调查人员将与华盛顿大学学校伙伴关系研究所和圣路易斯初中和高中的教师合作，开发一个“热门话题”网站和相关的讲习班，重点关注水质概念。为了鼓励高中生和本科生尽早参与科学和工程，他们将提供有关水质的科学研究项目和公开讲座。