Recent advances in degradation of micro/nanoplastics by sustainable photo-driven processes: A comprehensive review

Abstract

Micro/nanoplastics (MNPs) are pervasive environmental pollutants with significant ecological and health risks, prompting urgent research into sustainable degradation technologies. Photo-driven advanced oxidation processes (AOPs), including photolysis, photo-Fenton, and photocatalysis, have emerged as promising strategies for the oxidative breakdown of MNPs into less harmful compounds. Certain systems have demonstrated the capacity to achieve complete mineralization under optimized conditions. This review critically evaluates recent advances in these processes, integrating mechanistic insights, performance metrics, and environmental implications. Photolysis harnesses light to generate carbon-centered radicals and reactive oxygen species (ROS), while photo-Fenton and photocatalytic systems enhance ROS production through synergistic chemical and light-driven reactions. Recent breakthroughs include 100 % mineralization of polystyrene nanoplastics within minutes using photoelectro-Fenton and full degradation of PVC under visible-light-driven photocatalysis processes. The efficiency of these processes is further enhanced by co-factors such as inorganic minerals, organic acids, and halogen species, which promote ROS generation and surface oxidation. Despite these advances, critical challenges remain, including incomplete mineralization, potential formation of toxic intermediates, catalyst recyclability, methodological inconsistencies, and scalability limitations. Future research must focus on elucidating degradation pathways, developing selective and value-added conversion strategies, engineering visible-light-responsive, green-synthesized catalysts, integrating biological systems, and standardizing analytical protocols. By synthesizing recent progress and identifying key knowledge gaps, this review provides a comprehensive roadmap toward sustainable and scalable MNPs remediation technologies.