Micro- and nanoplastics in aquatic environments: Advances in detection methods and metal–organic framework (MOF)–based remediation

Abstract

Microplastics (MPs) and nanoplastics (NPs) are pervasive pollutants that persist in aquatic environments, transport toxic co-contaminants, and pose serious ecological and human health risks. Addressing this pressing challenge requires both accurate detection and effective remediation strategies. This review integrates recent advances in detecting MPs/NPs in environmental matrices, including spectroscopic, microscopic, and sensor-based approaches, with a critical assessment of metal–organic frameworks (MOFs) as advanced adsorbents for their removal. MOFs possess ultrahigh surface area, tunable chemistry, and versatile functionalization, enabling strong interactions with diverse polymers through adsorption, hydrophobic effects, π–π stacking, hydrogen bonding, and electrostatic forces. Reported removal efficiencies span 70–99.9 %, depending strongly on particle size, water chemistry, and MOF identity. UiO-66 and UiO-66-NH₂ achieved > 95 % removal of polystyrene NPs (<500 nm) in ultrapure water, where strong interfacial interactions dominate, whereas larger MPs (1–100 µm) exhibit lower efficiencies (70–85 %) even with high-surface-area frameworks like MIL-101(Cr) due to reduced surface contact and limited interfacial interactions. In natural waters, functionalized UiO and ZIF-8 frameworks show 80–90 % efficiencies, though performance declines under competition from natural organic matter and ionic species. Despite high adsorption and promising reusability, MOFs face cost and scalability challenges due to costly precursors, toxic solvents, and energy-intensive synthesis. Recent advances in green synthesis, the use of industrial by-products, and composite immobilization (hydrogels, foams) are steadily improving cost-effectiveness and long-term stability. Ultimately, integrating robust detection strategies with economically viable MOF-based remediation will be crucial to translating laboratory progress into practical and scalable solutions for MPs/NPs pollution.