Plastic products are used in almost all aspects of our daily life. Due to their low cost, portability, durability, and resistance to degradation, these products are affecting the health of the environment and biota on a global scale. Thus, the removal and mineralization of microplastics is an important challenge in the 21st century. Advanced oxidation processes (AOPs) have recently been identified as a viable treatment technique for tackling recalcitrant organic molecules and polymers. However, information on kinetic degradation mechanisms and photocatalytic reactor design is insufficient. This review discusses the fundamentals of photocatalysis and photo-Fenton processes in addition to the photocatalytic degradation mechanisms. We also introduce different characterization techniques of the major microplastic pollutants such as PE, PP, PVC, PS, PMMA, and PA66. In addition, a detailed overview of the major existing photocatalytic plants and the scaling-up methods of photoreactors are discussed.

This review synthesizes existing literature on microplastics in marine ecosystems from various oceanic regions. Microplastics in marine environment originate from a range of sources, including land-based activities, rivers inputs and oceanic-based sources such as fishing, aquaculture, tourism and extreme oceanic events. Methodological and technical limitations, like sampling, identification and quantification, as well as data reporting and analysis, are key constraints in microplastics research, making it difficult to evaluate plastic debris volume in different marine environments. Microplastics have colonized diverse oceans, even polar areas. Their spatial distribution is influenced by their physicochemical properties as well as factors influencing their transport including wind driven waves, current and colonization by microorganisms. The most prevalent polymers in various oceanic systems are PE, PP, and PS, accounting for more than 60% of recovered microplastics. Microplastics affect both unicellular and multicellular marine organisms at various structural levels, causing significant disruptions that negatively impact their ecological and biological functions as well as their social behavior. This threatens both human and ecosystem health. Microplastics significantly impact marine ecosystem services, with total potential losses estimated to be between 1.18 and 2.16 trillion USD, accounting for about 2% of global GDP. Microplastics impair blue carbon ecosystems, reducing their carbon sequestration capacity and exacerbating the economic costs associated with climate regulation and coastal protection. The existing regulatory frameworks addressing plastic pollution are synthesized to identify gaps and highlight opportunities for enhancing and implementing more effective, evidence-based regulations that promote environmental sustainability.