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The impact of organic-mineral interactions on soil organic matter stability and mineral evolution


EMSL Project ID
50632

Abstract

The aims of the proposed research are to: 1) determine the impact of adsorbed organics on mineral-solution interfacial structure, 2) understand how organics impact solution speciation during mineral nucleation, and 3) determine the mechanisms by which the interaction between organic components and mineralizing constituents stabilize soil organic matter and alter mineralization pathways. To accomplish these aims, we will apply a combination of NMR, AFM, SFG, classical DFT and TEM to probe solution speciation, define mineral-water interfacial structure, and track mineral nucleation and growth in situ at nm resolution. We will perform these measurements and simulations for a set of model materials systems in the presence of selected organics mineral nucleation and growth processes. The interaction between mineral surfaces and organic moieties common in soils has widespread impacts on environmental processes, including the persistence of soil organic matter (SOM) and the nucleation and growth of soil minerals. For example, long residence times of SOM are commonly attributed to sorption of organic species to mineral surfaces, which provide reactive sites for physical and chemical stabilization that prevent SOM degradation by enzymes and microbes. On the flip side, organics have a profound effect on mineralization pathways. For example, organic interactions with growing mineral surfaces can lead to inhibition or acceleration of mineral growth and interactions with solution species can redirect nucleation pathways via precursor phases. Our recent work has shed light on the mechanisms underlying both sets of processes — the stabilization of SOM by mineral surfaces and the modification of mineralization by organic constituents — but leaves many open questions about the speciation, structure and dynamics of interfacial regions. By filling those gaps our proposed research will provide new insights into the molecular mechanisms of SOM-mineral interactions and outcomes.

Project Details

Start Date
2018-11-19
End Date
2019-09-30
Status
Closed

Team

Principal Investigator

James De Yoreo
Institution
Pacific Northwest National Laboratory

Team Members

Kyle Kluherz
Institution
University of Washington

Caiyun Jia
Institution
Pacific Northwest National Laboratory

Sebastian Mergelsberg
Institution
Pacific Northwest National Laboratory

Aashish Tuladhar
Institution
Pacific Northwest National Laboratory

Guomin Zhu
Institution
University of Washington

Ying Chen
Institution
Pacific Northwest National Laboratory

Related Publications

Michael C. De Siena, Sidney E. Creutz, Annie Regan, Paul Malinowski, Qianni Jiang, Kyle T. Kluherz, Guomin Zhu, Zhong Lin, James J. De Yoreo, Xiaodong Xu, Jiun-Haw Chu, Daniel R. Gamelin. 2020. "Two-Dimensional van der Waals Nanoplatelets with Robust Ferromagnetism." Nano Letters 20 (3):2100-2106. 10.1021/acs.nanolett.0c00102