Photocatalytic processes as a potential solution for plastic waste management

Plastics have become a critical environmental problem due to their widespread use, high physico-chemical stability and the inefficiency of wastewater treatments. Despite the efforts to reduce production and to increase reuse and recycling, the current strategies for plastic waste treatment are not suitable to handle with the growing demand of plastics and the concomitant waste in an environmentally friendly manner. Herein, we review the existing strategies for the treatment of plastic waste, highlighting photocatalytic processes as a potential solution for the degradation of plastics. The possibility of incorporating photocatalysts to plastics during the production process could enhance their light-activated biodegradability. Parallelly, photocatalysts can be employed during waste treatment processes of non-biodegradable stable plastics. The scarcely studied factors affecting plastic photocatalytic degradation, namely catalyst type, reactor configuration, and radiation source (intensity and wavelength), are discussed, highlighting the role that photocatalytic processes can play in the future of plastic management. Finally, relevant quantification methods for measuring the photo-degradation of plastics are overviewed. We believe that photocatalysis can be an environmentally friendly strategy both to increase the biodegradability of plastics and to treat plastic waste. With this novel comprehensive overview, we hope to stimulate further research and innovation in this field.