Micro/nanoplastics removal from the aquatic environment using micro/nanobubbles-assisted flotation technology: A review

Micro/nanoplastics (MNPs) spark global concerns due to their dangers to the aquatic environment. Significant efforts are made to remove MNPs from the environment using innovative technologies. This work explores the progress of the flotation methods based on Micro/Nanobubbles (MNBs) for the MNPs elimination. The sources, distribution pathways, environmental, and health impacts of MNPs are discussed. The limitations of conventional technologies in MNPs removal draw attention to the advanced approaches like MNBs. MNBs are tiny gas-filled cavities with sizes ranging from micrometers to nanometers. Their unique characteristics, such as high surface area-to-volume ratios, elevated zeta potentials, and prolonged stability in water, enhance their application in purification processes. Therefore, the fundamental properties, generation techniques, and applications of these MNBs across diverse aquatic settings are reviewed. It is focused on the role of MNBs in enhancing the flotation-based removal of MNPs by addressing the flotation mechanisms, influencing factors (e.g., MNPs/MNBs properties, operational parameters), and process optimization. Finally, this work aims to evaluate the current limitations of scalability and assess future directions for implementing MNB-assisted flotation of MNPs remediation in real-world scenarios. It also highlights recent initiatives in plastic waste management focused on establishing regulatory frameworks and policies aimed at mitigating plastic pollution, thereby guiding researchers toward the development of innovative and effective flotation strategies for better management and mitigation of MNPs pollution in aquatic environments.