The Challenges and Urgent Need for Treatment and Monitoring of Micro- and Nano-Plastics in the Environment

Abstract

As global plastic production and inadequate waste management continue to increase, fragmentation and weathering accelerate the widespread occurrence of micro- and nanoplastics (MNPs) across environmental compartments. In this context, advanced oxidation processes (AOPs), particularly electrochemical advanced oxidation processes (EAOPs), have emerged as promising strategies for addressing MNPs contamination due to the generation of reactive species capable of inducing polymer transformation. Their performance depends on numerous factors including polymer properties, treatment configuration, electrode material, current density, supporting electrolyte, additives, and hybrid enhancement strategies. To date, most studies have been conducted under simplified laboratory conditions using heterogeneous protocols. However, in actual environmental and wastewater matrices, radical scavengers and coexisting constituents can suppress oxidation and alter degradation pathways. Moreover, particle-size reduction and changes in surface chemistry are often interpreted as degradation without confirming mineralization, carbon balance, transformation-product fate, or reduced toxicity. While electrochemical, spectroscopic, and microscopic techniques provide complementary information for monitoring these transformations, harmonized analytical workflows remain insufficiently adopted. Based on this critical assessment, this review integrates advanced oxidation and electrochemical strategies for MNPs treatment and monitoring, focusing on degradation mechanisms, electrochemical detection, complementary characterization, transformation products, toxicity, real-matrix effects, and scale-up challenges.