An Integrated Study Of The Controls On Reactivity Of Natural Organic Matter In Porous Media

发展对天然有机物(NOM)与矿物表面相互作用的分子尺度理解的工作将量化天然有机物(NOM)在矿物表面的优先吸附(吸附分馏)如何影响陆地有机碳的转化和污染物通过多孔介质的传输。分子尺度吸附研究将寻求了解表征NOM在土壤孔隙水和浅层地下水中的分子量分布的吸附机理，以确定对数正态分布模型是否也适用于地下环境。他们将量化NOM的吸附分级如何影响痕量金属的结合和移动性以及NOM的光化学反应活性。这三个主要目标是：(1)扩大分子尺度研究，目的是对NOM的吸附和分馏过程有更定量和更机械的了解；(2)确定吸附分馏对NOM在痕量金属结合方面的反应性和对光反应的迁移率的影响；(3)继续结合实验室和实地研究，最终的长期目标是更好地了解吸附/分馏现象在实地实际发生的情况。这项研究在水文科学中具有广泛的意义，因为NOM普遍存在，有助于控制矿质土壤团聚体的稳定性和光化学反应。至于实际应用，人们对控制供水中NOM性质的分水岭过程知之甚少。饮用水工业必须解决消毒剂的问题，使用氯或臭氧，这两种反应在很大程度上取决于非芳香性。

0106752CabanissThe work to develop molecular-scale understanding of the interactions of natural organic matter (NOM) with mineral surfaces would quantify how the preferential adsorption of higher molecular-weight and more aromatic NOM components to mineral surfaces (sorptive fractionation) affects both the transformation of terrestrial organic carbon and the transport of pollutants through porous media. The molecular-scale adsorption studies would pursue understanding of NOM adsorption mechanisms characterizing NOM molecular weight distributions in soil pore waters and shallow ground waters to determine whether the lognormal distribution model also holds in subsurface environments. They would quantify how sorptive fractionation of NOM affects the binding and mobility of trace metals and NOM photochemical reactivity. The three broad objectives are:(1) To expand molecular-scale studies aimed at developing a more quantitative and mechanistic understanding of NOM adsorption and fractionation processes;(2) To determine the effect of sorptive fractionation on NOM reactivity with respect to trace-metal binding and mobility with respect to photoreactions;(3) To continue to integrate laboratory and field studies, with the ultimate long-term goal of better understanding adsorption/fractionation phenomena as they actually occur in the field. The proposed research has broad significance within the hydrologic sciences, because NOM is ubiquitous and helps to control mineral soil aggregate stability, and photochemical reactions. As to practical applications, little is known about watershed processes controlling the nature of NOM in water supplies. The drinking water industry must address the problem of disinfectant, with chlorine or ozone and both reactivities depend in large part on NOM aromaticity.