Low Environmental Impact Remediation of Microplastics: Visible-Light Photocatalytic Degradation of PET Microplastics Using Bio-Inspired C,N-TiO2/SiO2 Photocatalysts

Microplastics (MPs) are plastic particles of ≤5 mm with a ubiquitous presence in aquatic ecosystems. MPs harm marine life and can cause severe health problems for humans. Advanced oxidation processes (AOPs) that involve the in-situ generation of highly oxidant hydroxyl radicals can be an alternative to fight MPs pollution. Of all the AOPs, photocatalysis has been proven a clean technology to overcome microplastic pollution. In this work, we propose novel C,N-TiO2/SiO2 photocatalysts with proper visible-active properties to degrade polyethylene terephthalate (PET) MPs. Photocatalysis was performed in an aqueous medium and at room temperature, evaluating the influence of two pH values (pH 6 and 8). The obtained results demonstrated the degradation of the PET MPs by C,N-TiO2/SiO2 semiconductors and achieved mass loss between 9.35 and 16.22%, carbonyl indexes up to 28.7% lower, and a significant decrease in crystallinity compared to the original PET MPs.