Advanced oxidation processes for microplastics degradation: A recent trend

Recently, microplastics (MPs) became a big name in the world since their presence in bodies of different species, environmental media, and even in bottled drinking water was frequently reported. Several studies reported MPs' potential threat to health of humans, animals and the ecosystem. Therefore, it is of great importance to develop reliable technologies for removing MPs in the environment. Advanced oxidation processes (AOPs) are widely studied and applied for the decomposition of different refractory contaminants in the environment. Because reactive oxygen species produced in AOPs could effectively degrade many pollutants, several AOPs were applied for MPs decomposition. Homogeneous and heterogeneous AOPs, including UV photolysis, UV/H2O2, O3, UV/ visible light-induced photocatalysis, heat activated PS and PMS, and plasma, could effectively decompose various types of MPs with different sizes. However, the decomposition mostly occurred on the surface of MPs even though several studies reported complete removal of MPs. Interestingly, several studies demonstrated that treated MPs could become pollutant carriers for animals and human beings by adsorbing contaminants in the environment. However, a limited number of studies on MPs removal by AOPs are available and only few types of AOPs are recently studied even though current studies demonstrated the potential of AOPs for complete MPs removal. Therefore, more effort must be put into investigating different AOPs for complete removal of MPs in the environment. AOPs will play a key role for MPs removal in the environment in the near future, definitely.