Nano-Earth sciences: Understanding environmental processes at the nano-scale

点击翻译按钮获取中文摘要

Canada's economy depends strongly on natural resources including mineral deposits. Mining of mineral deposits has led to the construction of tailings impoundments, particulate matter emissions from smelters, and generation of dust during mining activities. The proposed studies will provide fundamental knowledge on the fate of metals and metal(loids) in contaminated soils and sediments, abandoned tailings and tailings reclaimed using organic-rich soils. The proposed study will specifically examine Earth and Environmental processes at the nano scale (1-100 nm). Processes at this scale commonly control the fate of metal- and metalloid-bearing contaminants in soils, tailings, sediments and water. Environmentally relevant processes at the nano-scale are for example adsorption of contaminants on mineral surfaces, organic matter and nanoparticles, the transport of contaminant-bearing nanoparticles within soils, sediments and tailings and the formation, agglomeration, attachment and release of contaminant-bearing nanoparticles. An important aspect of these nano-scale processes is the interaction of surfaces of minerals and organic matter with contaminants dissolved in solution or attached or incorporated into nanoparticles. Although previous models of the interaction of contaminants with surfaces of minerals and organic matter assumed that the surfaces of both constituents are relatively homogeneous in composition and that the environmental conditions on and within these materials are relatively constant; recent studies show that this is not the case: mineral surfaces and organic matter have been chemically altered and the environmental conditions in these altered entities vary on the nano-scale. Hence, mineral surfaces and organic matter are far more complex than previously assumed. The proposed study will explore the interaction of contaminants within altered mineral surfaces and organic matter such as roots, bacteria and litter from plants and trees. This study uses instruments in specialized laboratories in Canada and the USA that allow the visualization of chemical processes on the nano-scale.