Interactions between titanium dioxide nanoparticles and polyethylene microplastics : adsorption kinetics, photocatalytic properties, and ecotoxicity

Kalčíková, Gabriela (author), Roy, Rajdeep (author), Klun, Barbara (author), Rozman, Ula (author), Marolt, Gregor (author), Skalar, Tina (author), Feckler, Alexander (author), Bundschuh, Mirco (author)

The present study investigated the adsorption mechanism of titanium dioxide nanoparticles (nTiO$_2$) on polyethylene microplastics (MPs) and the resulting photocatalytic properties. This effort was supported by ecotoxicological assessments of MPs with adsorbed nTiO$_2$ on the immobility and behaviour of Daphnia magna in presence and absence of UV irradiation. The results showed that nTiO$_2$ were rapidly adsorbed on the surface of MPs (72% of nTiO$_2$ in 9 h). The experimental data fit well with the pseudo-second order kinetic model. Both suspended nTiO$_2$ and nTiO$_2$ immobilized on MPs exhibited comparable photocatalytic properties, with the latter showing a lower effect on Daphnia mobility. A likely explanation is that the suspended nTiO$_2$ acted as a homogeneous catalyst under UV irradiation and generated hydroxyl radicals throughout the test vessel, whereas the nTiO$_2$ adsorbed on MPs acted as a heterogeneous catalyst and generated hydroxyl radicals only locally and thus near the air-water interface. Consequently, Daphnia, which were hiding at the bottom of the test vessel, actively avoided exposure to hydroxyl radicals. These results suggest that the presence of MPs can modulate the phototoxicity of nTiO$_2$ – at least the location at which it is active – under the studied conditions.

• Language: English
• Keywords: adsorption, freshwaters, microbeads, nanoparticles, reactive oxygen species
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2023
• Number of pages: 8 str.
• Numbering: Vol. 329, art. 138628
• PID: 20.500.12556/RUL-145903
• UDC: 504.5:620.3:678.742.2
• ISSN on article: 0045-6535
• DOI: 10.1016/j.chemosphere.2023.138628
• COBISS.SI-ID: 149524739
• Publication date in RUL: 17.05.2023

Record is a part of a journal

• Title: Chemosphere
• Shortened title: Chemosphere
• Publisher: Pergamon Press.
• ISSN: 0045-6535
• COBISS.SI-ID: 25213696

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: nanodelci, titanov dioksid, polietilen, mikroplastika, adsorpcija