Quantifying nanoparticles in clays and soils with a small-angle X-ray scattering method
| Autor: | Masaya Suzuki, Katsuhiro Tsukimura |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Colloidal silica Astrophysics::High Energy Astrophysical Phenomena smectite Analytical chemistry Nanoparticle 02 engineering and technology 010402 general chemistry 01 natural sciences ferrihydrite General Biochemistry Genetics and Molecular Biology Physics::Geophysics allophane chemistry.chemical_compound Kaolinite colloidal silica Allophane nanoparticles in clays and soils kaolinite Small-angle X-ray scattering Silica gel quantitative analysis of nanoparticles silica gel 021001 nanoscience & nanotechnology Physics::Classical Physics Research Papers 0104 chemical sciences Montmorillonite chemistry small-angle X-ray scattering pyrophillite Absorption (chemistry) 0210 nano-technology |
| Zdroj: | Journal of Applied Crystallography |
| ISSN: | 1600-5767 0021-8898 |
| Popis: | This paper describes a method to quantify nanoparticles in clays and soils with small-angle X-ray scattering. Clays and soils produce strong small-angle X-ray scattering (SAXS) because they contain large numbers of nanoparticles, namely allophane and ferrihydrite. These nanoparticles are amorphous and have approximately spherical shape with a size of around 3–10 nm. The weight ratios of these nanoparticles will affect the properties of the clays and soils. However, the nanoparticles in clays and soils are not generally quantified and are sometimes ignored because there is no standard method to quantify them. This paper describes a method to quantify nanoparticles in clays and soils with SAXS. This is achieved by deriving normalized SAXS intensities from unit weight of the sample, which are not affected by absorption. By integrating the normalized SAXS intensities over the reciprocal space, one obtains a value that is proportional to the weight ratio of the nanoparticles, proportional to the square of the difference of density between the nanoparticles and the liquid surrounding the nanoparticles, and inversely proportional to the density of the nanoparticles. If the density of the nanoparticles is known, the weight ratio of the nanoparticles can be calculated from the SAXS intensities. The density of nanoparticles was estimated from the chemical composition of the sample. Nanoparticles in colloidal silica, silica gels, mixtures of silica gel and α-aluminium oxide, and synthetic clays have been quantified with the integral SAXS method. The results show that the errors of the weight ratios of nanoparticles are around 25% of the weight ratio. It is also shown that some natural clays contain large fractions of nanoparticles; montmorillonite clay from the Mikawa deposit, pyrophillite clay from the Shokozan deposit and kaolinite clay from the Kanpaku deposit contain 25 (7), 10 (2) and 19 (5) wt% nanoparticles, respectively, where errors are shown in parentheses. |
| Databáze: | OpenAIRE |
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