Recent advances on nanotechnology-driven strategies for remediation of microplastics and nanoplastics from aqueous environments

Microplastics and nanoplastics (MNPs) are emerging water and wastewater pollutants having high toxicity, strong affinity to other pollutants, solid resilience in water, and low rate of degradation, while their presence in wastewater causes disturbance in treatment plants. Nanotechnology-based strategies have been demonstrated to play a crucial role in water and wastewater treatment by combating various challenging MNP pollutants with high efficiency. This review presents methods that use nanomaterials to enhance the performance of water treatment processes toward removal of MNPs. Adsorption, photocatalysis, and membrane filtration are the main processes in which nanomaterials can help remediate MNP pollution. This is due to the properties of nanomaterials that include high surface-to-volume ratio, tunable surface charges, variable functionalities, and lower required dosage. Through recent literature, we critically assess property-performance relations, while challenges and gaps such as quantification, impact of other contaminants, and consideration of the size and shape of MNPs are highlighted. Process-specific considerations and limitations that can trigger further research and development are suggested.