Indirect daylight oxidative degradation of polyethylene microplastics by a bio-waste modified TiO2-based material

Paola Amato; Marzia Fantauzzi; Filomena Sannino; Ida Ritacco; Giuseppe Santoriello; Matteo Farnesi Camellone; Claudio Imparato; Aurelio Bifulco; Giuseppe Vitiello; Lucia Caporaso; Antonella Rossi; Antonio Aronne

doi:10.1016/j.jhazmat.2023.132907

Indirect daylight oxidative degradation of polyethylene microplastics by a bio-waste modified TiO₂-based material

J Hazard Mater. 2024 Feb 5:463:132907. doi: 10.1016/j.jhazmat.2023.132907. Epub 2023 Nov 2.

Affiliations

¹ Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale V. Tecchio 80, I-80125 Naples, Italy.
² Department of Chemical and Geological Sciences, University of Cagliari, Campus of Monserrato, I-09042 Monserrato, Cagliari, Italy.
³ Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, I-80055 Portici, Naples, Italy. Electronic address: filomena.sannino@unina.it.
⁴ Department of Chemistry and Biology "A. Zambelli", INSTM Research Unit, University of Salerno, I-84084 Fisciano, Salerno, Italy.
⁵ CNR-IOM, Consiglio Nazionale delle Ricerche - Istituto Officina dei Materiali, I-34136 Trieste, Italy.
⁶ Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale V. Tecchio 80, I-80125 Naples, Italy; CSGI, Center for Colloid and Surface Science, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Florence, Italy.
⁷ Department of Chemistry and Biology "A. Zambelli", INSTM Research Unit, University of Salerno, I-84084 Fisciano, Salerno, Italy. Electronic address: lcaporaso@unisa.it.
⁸ Department of Chemical and Geological Sciences, University of Cagliari, Campus of Monserrato, I-09042 Monserrato, Cagliari, Italy. Electronic address: rossi@unica.it.
⁹ Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale V. Tecchio 80, I-80125 Naples, Italy. Electronic address: anaronne@unina.it.

PMID: 37939563
DOI: 10.1016/j.jhazmat.2023.132907

Abstract

Microplastics are recognized as an emerging critical issue for the environment. Here an innovative chemical approach for the treatment of microplastics is proposed, based on an oxidative process that does not require any direct energy source (irradiation or heat). Linear low-density polyethylene (LLDPE) was selected as target commodity polymer, due to its widespread use, chemical inertness and inefficient recycling. This route is based on a hybrid material coupling titanium oxide with a bio-waste, rosin, mainly constituted by abietic acid, through a simple sol-gel synthesis procedure. The ligand-to-metal charge transfer complexes formed between rosin and Ti⁴⁺ allow the generation of reactive oxygen species without UV irradiation for its activation. In agreement with theorical calculations, superoxide radical ions are stabilized at ambient conditions on the surface of the hybrid TiO₂. Consequently, an impressive degradation of LLDPE is observed after 1 month exposure in a batch configuration under indirect daylight, as evidenced by the products revealed by gas chromatography-mass spectrometry analysis and by chemical and structural modifications of the polymer surface. In a context of waste exploitation, this innovative and sustainable approach represents a promising cost-effective strategy for the oxidative degradation of microplastics, without producing any toxic by-products.

Keywords: Advanced oxidation process; LLDPE; Polymer degradation; Rosin; Titanium dioxide.