Advancing photocatalytic strategies for microplastic degradation in aquatic systems: Insights into key challenges and future pathways

Microplastic pollution has become a global environmental concern due to its persistence, ubiquity, and potential adverse effects on ecosystems and human health. With global plastic production projected to quadruple from 380 million metric tons in 2015 to 1520 million metric tons by 2050, and 80 % of plastic waste accumulating in the environment, photocatalysis has emerged as a promising approach for addressing this challenge, offering the ability to degrade microplastics into less harmful byproducts through light-activated chemical reactions. This review comprehensively analyzes advancements in photocatalytic systems for microplastic degradation, emphasizing the development of innovative materials such as doped semiconductors, heterojunctions, and metal-organic frameworks, which enhance light absorption, charge separation, and catalytic efficiency. This review explores how these advancements improve performance, addressing key limitations of conventional photocatalysts. Integration of photocatalysis with other technologies is discussed, to improve degradation rates and energy efficiency while mitigating secondary pollution. Challenges related to scaling photocatalytic technologies for real-world applications, such as the need for efficient reactor designs and consistent performance under natural conditions are critically evaluated. Additionally, the environmental implications of byproducts generated during microplastic degradation are examined, emphasizing the importance of standardized methodologies to assess catalyst efficiency and ensure environmental safety. This review highlights emerging strategies to valorize degradation byproducts into useful resources, advancing the sustainability of photocatalytic processes. By addressing gaps in hybrid system innovation, scalability, and resource recovery, this review provides unique insights that integrate these critical aspects for advancing the practical application of photocatalytic technologies. • Photocatalytic degradation effectively targets varied microplastic polymer types. • UV-Vis active catalysts show promise in utilizing sunlight to reduce microplastics. • Photocatalysis can revalorize microplastics, turning them into valuable chemicals. • Hybrid photocatalytic systems enhance efficiency in microplastic degradation. • Lack of standardization complicates comparison between experiments and scaling-up.