Using molecular-scale approaches to understand soil chemical processes

使用分子尺度方法了解土壤化学过程

• 批准号: 261432-2013
• 负责人: Peak, John
• 金额: $ 3.5万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=634238
• 关键词: Using; molecular; scale; approaches; understand

Chemical reactions in soils often control the mobility, toxicity, and availability of nutrients and contaminants in natural systems. Understanding precisely how soil chemical reactions proceed is therefore vital in assessing environmental fate. A recurring theme in the study of soil chemistry is that the most reactive soil surfaces are not the bulk crystalline minerals that make up 90-95% of soil, but instead are the highly reactive poorly-crystalline nano-minerals that form coatings on larger soil particles. The objective of this research is to better understand the factors that lead to the persistence and reactivity of two of these phases (ferrihydrite and dicalcium phosphates) that are important for both environmental and agronomic reasons. To accomplish this objective, we will use synchrotron-based X-ray Absorption Spectroscopy (XAS) at the Canadian Light Source. This method provides direct measurement of both the nano-mineral structure and details of how contaminants bond to those those minerals under hydrated conditions. This research in this program will improve the fundamental understanding of soil chemistry and the results will be important for agriculture in both temperate and tropical climates, environmental geochemistry and contaminant chemistry. This project also explores relationships between soil chemical processes with metal-organic frameworks; this could lead to major advances in our understanding of soil organic matter. Finally, the EEMS technique will be useful for a wide range of natural resource-related problems, including oil sands extractions, evaluating mining ores and tailings, and mineral exploration.

土壤中的化学反应通常控制自然系统中养分和污染物的流动性、毒性和可用性。因此，准确了解土壤化学反应如何进行对于评估环境命运至关重要。土壤化学研究中反复出现的一个主题是，最具反应性的土壤表面并不是占土壤 90-95% 的大块结晶矿物，而是在较大土壤颗粒上形成涂层的高反应性弱结晶纳米矿物。本研究的目的是更好地了解导致其中两个相（水铁矿和磷酸氢钙）持久性和反应性的因素，这两个相对于环境和农艺原因都很重要。为了实现这一目标，我们将在加拿大光源处使用基于同步加速器的 X 射线吸收光谱 (XAS)。该方法提供了纳米矿物结构的直接测量以及污染物在水合条件下如何与这些矿物结合的详细信息。该项目的研究将提高对土壤化学的基本了解，其结果对于温带和热带气候的农业、环境地球化学和污染物化学具有重要意义。该项目还探讨了土壤化学过程与金属有机框架之间的关系；这可能会导致我们对土壤有机质的理解取得重大进展。最后，EEMS 技术将可用于解决各种与自然资源相关的问题，包括油砂开采、评估采矿矿石和尾矿以及矿物勘探。