Nucleation of Manganese Oxides in the Presence of Reactive Halogen Species

活性卤素物质存在下锰氧化物的成核

基本信息

批准号：
1905077
负责人：
Young-Shin Jun
金额：
$ 44.92万
依托单位：
Washington University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2023-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905077&HistoricalAwards=false
关键词：
Nucleation Manganese Oxides Presence Reactive

项目摘要

Funded by the Environmental Chemical Sciences Program of the NSF Division of Chemistry, Professor Young-Shin Jun at Washington University examines the formation of manganese oxide particles in salt water. Manganese oxides are environmentally abundant and are important in removing contaminants. Their formation can be affected by products from human activities that have high salt concentrations, such as from desalination and oil and gas recovery. The chemical reactions involved are poorly understood, including the roles of halide ions (e.g., chloride and bromide) and highly reactive halogen species. This work quantitatively and qualitatively examines how salt water chemistry affects the formation of manganese oxides in the environment. The project also develops environmental chemistry outreach programs for underrepresented or economically disadvantaged K-12 students. This outreach both encourages the early involvement of high school and undergraduate students in research and improves university courses by incorporating research outcomes.The increased production of highly saline effluents from water and energy generating processes raises questions about their impacts on the environment. In particular, halides in brine can greatly affect mineral formation and dissolution processes in natural aquatic systems. With sunlight, halides may further undergo photochemical reaction to generate reactive radical species. However, the effects of halides under sunlight exposure on redox-active transition metal ions and their solid phase formation are still obscure. This project investigates the effects of reactive halogen species on the oxidation of aqueous manganese (Mn) ions and the kinetics of the nucleation and growth of Mn particles, with and without natural organic matter. It is hypothesized that reactive species generated from reactions between natural organic matter and halides during their photolysis can promote the photochemical oxidation of Mn2+ (aq) and facilitate the formation of higher oxidation states of manganese oxides. To elucidate the properties of newly formed manganese oxides and to examine these dynamic redox reaction behaviors, solid phases of manganese oxides and fluid chemistries are characterized. In situ synchrotron-based small angle x-ray scattering provides real-time information about the nucleation and growth of manganese oxides. The project advances fundamental knowledge regarding the nucleation mechanisms and kinetics of manganese oxides in highly saline systems, which is important for predicting contaminant removal and transport and for developing new manganese-based materials.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.

华盛顿大学的Young-shin Jun教授由NSF化学部的环境化学科学计划资助，研究了盐水中锰氧化物颗粒的形成。锰氧化物在环境上很丰富，对于去除污染物很重要。它们的形成可能会受到具有高盐浓度的人类活动的产品，例如海水淡化以及石油和天然气回收。涉及的化学反应知之甚少，包括卤化物离子（例如氯化物和溴化物）和高反应性卤素物种的作用。这项工作定量和定性地研究了盐水化学如何影响环境中锰氧化物的形成。该项目还为代表性不足或经济不利的K-12学生制定了环境化学外展计划。这种推广既鼓励高中早期参与研究，并通过纳入研究成果来改善大学课程。从水和能源产生过程中增加了高盐水废水的产量增加了有关其对环境的影响的问题。特别是，盐水中的卤化物会极大地影响天然水生系统中的矿物质形成和溶解过程。在阳光下，卤化物可能会进一步发生光化学反应以产生反应性自由基物种。然而，阳光下暴露在氧化还原活性过渡金属离子及其固相的形成仍然晦涩的影响。该项目研究了反应性卤素物种对具有和没有天然有机物的有和没有天然有机物的Mn颗粒的成核和生长的动力学的氧化以及成核和生长的动力学的影响。假设在光解过程中，由天然有机物和卤化物之间的反应产生的反应物质可以促进MN2+（水溶液）的光化学氧化，并促进形成较高的锰氧化物氧化态。为了阐明新形成的锰氧化物的特性并检查了这些动态氧化还原反应行为，表征了锰氧化物和液体化学的固体相。基于原位同步加速器的小角度X射线散射提供了有关锰氧化物成核和生长的实时信息。该项目促进了有关高盐水系统中锰氧化物的成核机制和动力学的基本知识，这对于预测污染物的去除和运输以及开发基于新的锰的材料非常重要。该奖项反映了NSF的法定任务，并通过该基金会的知识优点和广泛的影响来通过评估来进行评估，并通过评估值得进行评估。