Data from: Particle dynamics of nanoplastics suspended in water with soil microparticles: Insights from small angle neutron scattering (SANS) and ultra-SANS
Data files
Jan 06, 2025 version files 534.50 KB
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Fig_1.xlsx
12.35 KB
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Fig_3.xlsx
133.65 KB
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Fig_4.xlsx
13.10 KB
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Fig_S6.xlsx
109.50 KB
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Fig_S7.xlsx
129.22 KB
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README.md
5.56 KB
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SANS_USANS_data.xlsx
131.14 KB
Abstract
Small-angle neutron scattering (SANS) and Ultra-SANS (USANS) were employed to understand the agglomeration behavior of nanoplastics (NPs) formed from a biodegradable mulch film, and microparticles of vermiculite (V), an artificial soil, suspended in water in the presence of low convective shear (ex-situ stirring) prior to measurements. Neutron contrast matching was employed to minimize the signal of V (by 100-fold) and thereby isolate the signal due to NPs in the neutron beam, as the contrast match point (CMP) for V (67 vol% deuteration in water) differed from that of NPs by more than 20%. The original NPs’ size distribution was bimodal: < 200 nm and 500-1200 nm, referred to as small and large NPs, i.e., SNPs and LNPs, respectively. In the absence of V, SNPs formed agglomerates at higher concentrations, with size decreasing slightly with stirring time to 40-50 nm, while the size of LNPs remained unchanged. The presence of V at 2-fold lower concentration than NPs did not change the size of SNPs but reduced the size of LNPs by nearly 2-fold as stirring time increased. Because the size of SNPs and LNPs did not differ substantially between solvents, both at CMP and 100% D2O, even with nanosized V particles contributing toward scattered intensity for the latter solvent, it is evident that SNPs and LNPs are mainly composed of NPs and not V. The results suggest that LNPs are susceptible to size reduction through collisions with soil microparticles via convection, yielding SNPs near soil-water interfaces within vadose zones.
https://doi.org/10.5061/dryad.2z34tmpws
Description of the data and file structure
Files and variables
File: Fig_1.xlsx
Description: Fig. 1 Recovery yield (%) of vermiculite (V_only), nanoplastics (NPs_only), and their mixture in metastable suspensions (1% and 5% NP+V) after centrifugation for (A) CMP and (B) 100% D2O solvents at various ex-situ stirring times (0, 24, 168 hours). Error bars represent the standard error of the measurements.
Variables
- Nanoplastic concentration (0, 1 wt% or 5%), vermiculite concentration (0 or 5 wt%), stirring time (0 h, 24 h, 168 h), solvent type (Contrast Match Point [CMP], D2O], % Recovery (average), % Recovery (error)
File: Fig_3.xlsx
Description:
**Fig 3. **Model fitting of oscillations for SANS and USANS scattering data after subtraction of the power law **(Eq. 2) from I(Q) (Fig. 2) **for suspensions of **(A, B) **NPs (1 %); (C, D) NPs (1%) + V (0.5%), and (E, F) NPs (5%) + V (0.5%) in contrast matching solvent for V (67% D2O / 33% H2O) at 22oC. (A, C, E) USANS data fitted by a Schulz polydisperse sphere form factor model (Eq. 4) for large NPs (LNPs) and (B, D, F) SANS data fitted by a lognormal form factor model (Eq. 3) for small NPs (SNPs). Blue font represents data derived from model fits to the SANS and USANS data, while black font represents the SANS and USANS data that was collected.
Variables
- Nanoplastic concentration (0, 1 wt% or 5%), vermiculite concentration (0 or 5 wt%), stirring time (0 h, 24 h, 168 h), SANS data: scattering angle (Q), scattered intensity after subtraction of power law [I(Q)], error for I(Q), Model fits to SANS data at low- and high-Q: Q, I(Q), error for I(Q)
File: SANS_USANS_data.xlsx
Description: Merged SANS and USANS data used in Figures 2 and S1-S5.·Figs S1-S3 contain plots of the raw data given below. Figs 2, S4, and S5 contain plots of the same raw data, but with I(Q) multiplied by a constant (as given in the figure captions) in several cases to improve visualization. Data were fit by power law models, Eq. 2, with the equation parameters given in Table S1. If an entry for Error in I(Q) is blank, the value is zero. Blue and black font represent data derived from SANS and USANS, respectively, representing Small NPs and Large NPs, respectively.
Variables
- Nanoplastic concentration (0, 1 wt% or 5%), vermiculite concentration (0 or 5 wt%), stirring time (0 h, 24 h, 168 h), solvent type (Contrast Match Point [CMP], D2O], SANS data: scattering angle (Q), scattered intensity [I(Q)], error for I(Q)
File: Fig_4.xlsx
Description: Fig. 4. Box plots for size of NPs or their agglomerates suspended in aqueous suspensions at the CMP of V (67 vol% D2O/33% H2O): (A) SNPs and (B) LNPs vs. *ex-situ *stirring time and NP and V concentrations and NPs or their agglomerates suspended in 100% D2O: (C) SNPs and (D) LNPs vs. *ex-situ *stirring time and NP and V concentration.
Variables
- Nanoplastic concentration (0, 1 wt% or 5%), vermiculite concentration (0 or 5 wt%), stirring time (0 h, 24 h, 168 h), solvent type (Contrast Match Point [CMP], D2O], Nanoplastic size: median, top and bottom of box, top and bottom of whiskers.
File: Fig_S6.xlsx
Description: **Fig S6. **Model fitting of oscillations for SANS and USANS scattering data after subtraction of the power law **(Eq. 2) from I(Q) (Fig. 2) **for suspensions of **(A, B) **NPs (1 %); (C, D) NPs (1%) + V (0.5%), and (E, F) NPs (5%) + V (0.5%) in 100% D2O at 22C. (A, C, E) USANS data fitted by a Schulz polydisperse sphere form factor model (Eq. 4) for large NPs (LNPs) and (B, D, F) SANS data fitted by a lognormal form factor model (Eq. 3) for small NPs (SNPs). Blue font represents data derived from model fits to the SANS and USANS data, while black font represents the SANS and USANS data that was collected.
Variables
- Nanoplastic concentration (0, 1 wt% or 5%), vermiculite concentration (0 or 5 wt%), stirring time (0 h, 24 h, 168 h), SANS data: scattering angle (Q), scattered intensity after subtraction of power law [I(Q)], error for I(Q), Model fits to SANS data at low- and high-Q: Q, I(Q), error for I(Q)
File: Fig_S7.xlsx
Description: **Fig. S7. Histograms of particle size **distributions for NPs derived from the curve fitting of SANS and USANS data, after subtraction of Eq. 2, provided by Igor and Irena software, which represents average particle size reduction because of ex-situ stirring. Smaller-sized NPs (SNP) represent the lognormal fit and larger-sized NPs (LNPs) by polydisperse spheres (Schulz distribution). Blue and black font represent data derived from SANS and USANS, respectively, representing Small NPs and Large NPs, respectively.
Variables
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- Nanoplastic concentration (0, 1 wt% or 5%), vermiculite concentration (0 or 5 wt%), stirring time (0 h, 24 h, 168 h), solvent type (Contrast Match Point [CMP], D2O], particle diameter (nm), volume distribution
Code/software
Microsoft Excel (filename.xlsx); version 2010 or later.
Access information
Other publicly accessible locations of the data:
- Not applicable
Data was derived from the following sources:
- Not applicable
Data for Fig 1 (nanoplastic recovery suspended in water and settling out) was collected in the laboratory and the results were recorded in a Microsoft Excel file. Other data was collected on the small-angle neutron scattering (SANS) and ultra-SANS instruments at Oak Ridge National Laboratory, specifically, the Bio-SANS (high-flux isotope reactor) and Beamline 1A (spallation neutron source), respectively (downloaded into Microsoft Excel files and displayed in Figs 2 and S1-S5). Data for Figs 3 and S6 include form factor-structure factor modeling of merged SANS and USANS data, after subtraction of a power law relationship. Modeling was done using Igor Pro-based software written by National Institute of Standards scientists and the model fits to the data and resultant parameters were downloaded to Microsoft Excel files. The models' parameters allowed for determination of box plots and histograms of nanoplastic size and size distribution under several different conditions, Figs 4 and S7, respectively. The latter two figures were generated using JMP software, and were subsequently downloaded to Microsoft Excel files.