Chemical and Morphological Fingerprinting of Engineered Nanomaterials in Soil for Identification of Source, Age, and Environmental History
Abstract
Many engineered nanomaterials (ENMs) that are used or proposed for use in military operations are made from earth-abundant elements like aluminum and titanium (e.g. nano-aluminum obscurants). To date, technical limitations of analytical methods makes it challenging to find and quantify these ENMs, especially in soil due to high background metal concentrations or high numbers of natural nanomaterials (NMs) containing similar elements. However, a powerful new analytical tool, single-particle inductively coupled plasma time-of-flight mass spectrometry (spICP-TOF-MS) can be used to measure the chemical fingerprint of 10Õs of thousands of individual ENMs and natural NMs recovered from the soil. The unique fingerprints provided by chemical impurities in ENMs, along with their unique morphology relative to natural NMs, may provide information about the sources, ages or history of those ENMs. Here, we propose to (1) determine how the fingerprints (based on the chemistry and the morphology) of ENMs made from earth-abundant elements (Al and Ti) can be used to identify ENM sources and distinguish them from natural NMs, (2) determine how transformations of the introduced ENMs due to natural weathering and/or microbiological processes affect their fingerprints, and (3) use the acquired database to design pattern recognition algorithms to identify ENMs in soil. We develop methods to extract and concentrate ENMs and natural NMs from soil matrices. The chemical fingerprints of the extracted ENMs and natural NMs are measured using spICP-TOF-MS, and the morphological signatures are determined by electron microscopy along with shape recognition. Statistical analysis of these morphological and chemical fingerprints will be used to identify and quantify ENMs in a soil matrix, and to assess the changes in the chemical fingerprint and morphology due to transformations during aging in the soil. We will use the knowledge gained with Al- and Ti-based model ENMs and four model natural soil types to propose a generalized framework for distinguishing the sources of ENMs in different or unknown soils. These methods will enable the identification of selected ENMs in soils, the sources of those ENMs based on their unique chemical signature, and morphology, and potentially, their environmental history.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1910063
Entities
People
- Gregory V. Lowry
Organizations
- Army Contracting Command
- Massachusetts Institute of Technology
- United States Army