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 with sizes between 1 μm and 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. This work proposes 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 results demonstrated that the degradation of the PET MPs by C,N-TiO2/SiO2 semiconductors is possible, achieving mass losses between 9.35 and 16.22 %. •Microplastics (MPs) harm marine life and can cause health problems to humans.•Photocatalytic degradation by C,N-TiO2/SiO2 is proposed for fighting MPs pollution.•Synthesis of C,N-TiO2/SiO2 used the EPF of M. edulis &M. galloprovincialis mussels.•Both C,N-TiO2/SiO2 samples yield similar photocatalytic properties.•PET MPs were degraded at pH 6 or 8, achieving 9.35–16.22 % of mass loss.