Data on sorption of organic compounds by aged polystyrene microplastic particles

This article contains data on experimental sorption isotherms of 21 probe sorbates by aged polystyrene microplastics. The polymeric particles were subjected to an UV-induced photo-oxidation procedure using hydrogen peroxide in a custom-made aging chamber. Sorption data were obtained for aged particles. The experimental sorption data was modelled using both single- and poly-parameter linear free-energy relationships. For discussion and interpretation of the presented data, refer to the research article entitled “Sorption of organic compounds by aged polystyrene microplastic particles” (Hüffer et al., 2018) [1].


a b s t r a c t
This article contains data on experimental sorption isotherms of 21 probe sorbates by aged polystyrene microplastics. The polymeric particles were subjected to an UV-induced photo-oxidation procedure using hydrogen peroxide in a custom-made aging chamber. Sorption data were obtained for aged particles. The experimental sorption data was modelled using both single-and poly-parameter linear free-energy relationships. For discussion and interpretation of the presented data, refer to the research article entitled "Sorption of organic compounds by aged polystyrene microplastic particles" (Hüffer et al., 2018) [1].
& 2018 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Analyzed data Experimental factors
Polystyrene microplastics were exposed to an UV-induced photo-oxidation procedure with H 2 O 2 Experimental features Sorption isotherms of 21 probe sorbates were performed using UV-aged polystyrene microplastics as sorbent Data source location Vienna, Austria Data accessibility The data are available within this article Value of the data • Sorption isotherm data for UV-aged polystyrene microplastic were determined for 21 molecular probe sorbates covering a broad spectrum of molecular substance classes. • Modelling data provided information for the interpretation of molecular interactions between UVaged polystyrene microplastics and organic compounds. • Modelling data are valuable for the prediction of sorption by UV-aged polystyrene microplastics and allow a comparison with data from other aging processes and environmentally relevant polymers particles.

Data
Physico-chemical properties of the probe sorbates are given in Table 1. Fig. 1 shows sorption kinetics data of naphthalene by aged polystyrene microplastics (PSMP). Freundlich model fit data from sorption isotherms are shown in Table 2. A comparison of Freundlich fit model data between pristine and UV-aged polystyrene microplastics is given in Table 3. Data from statistical analyses of poly-parameter linear free-energy relationship model are shown in Tables 4-7. Single-parameter  [4] or calculated using a combination of Eq. (6)-(15) and (6)-(17) from ref [4]: linear free-energy relationships for sorption of organic compounds by PS micro-and nanoplastics are given in Table 8. Fig. 2 visualizes the correlation between experimental distribution coefficients of probe sorbates by aged polystyrene microplastics and octanol-water partitioning coefficients.

Materials
Polystyrene microplastics were purchased as a powder from Goodfellow Cambridge Ltd. (Huntingdon, UK.). The particles were sieved to a size fraction between 125 and 250 µm. The sorbates included apolar aliphatics, monopolar aliphatics, bipolar aliphatics, non-polar aromatics, monopolar aromatics, and bipolar aromatics (Table 1). Table 3 Comparison of Freundlich parameters obtained for pristine and aged polystyrene microplastic particles.

Aging of polystyrene microplastic particles
A custom-made aging chamber was used for particle aging. The particles were weighed into quartz glass petri dishes containing 50 mL of H 2 O 2 (10 vol%). The samples were then irradiated for 96 hours using UV light (4*15 W UVC-bulbs, max. wavelength at 254 nm). The aged particles were washed with deionized water and dried prior to the sorption batch experiments.

Sorption experiments
20-60 mg of the sorbent particles were weighed into 20-mL amber headspace screw vials. 10 mL of 0.01 M CaCl 2 was added as background solution. The vials were closed with screw caps with butyl/ PTFE-lined septa and wrapped in aluminum foil. After shaking overnight at 125 rpm to pre-wet the sorbent, the samples were spiked with sorbate standard solutions (methanol did not exceed 0.5%, to avoid co-solvent effects). The vials were then shaken for 7 days at 125 rpm for equilibration at a temperature of 25 7 2°C. Equilibration was determined using naphthalene as a probe sorbate (Fig. 1). The vials were then placed on the tray of the autosampler at least 2 hours prior to analysis. The concentrations in the head space of the vials was measured with a GC-MS-system either using intube microextraction or direct injection of 500 µL of the headspace sample. The sorbed concentrations were calculated using a mass balance and the air-water partitioning constants of the sorbates ( Table 1).

Data analysis
Distribution coefficients between the aqueous phase and the sorbent (K d ) [L/kg] were calculated for all sorbates at a constant sorbate loading on aged PSMP of 1000 µg/kg, using the Freundlich equation: where C s [μg/kg] and C w [μg/L] are the sorbed and aqueous concentrations of sorbates at equilibrium, respectively, and K F [(μg/kg)/(μg/L) 1/n ] and n [-] are the Freundlich coefficient and exponent, respectively. Model parameters were obtained using Sigma Plot 12.0 software for Windows.

Declarations of interest
None.

Transparency document. Supplementary material
Transparency document associated with this article can be found in the online version at http://dx. doi.org/10.1016/j.dib.2018.03.053.