Hierarchically Porous Silsesquioxane-Polyimide Aerogels for High-Throughput Separation of Microplastics from Complex Water Matrices

Abstract

The pervasive accumulation of microplastics (MPs) in aquatic environments poses a severe global threat, yet conventional membrane filtration suffers from rapid membrane fouling and low throughput. In this study, we report the fabrication of a silsesquioxane-cross-linked polyimide (PIOA) aerogel for highly efficient and robust MP remediation. Acting as critical 3D structural nodes, silsesquioxane (SQs) endow the aerogel with a highly interconnected hierarchically porous network and an ultralow, tunable apparent density. The optimized aerogel exhibits an exceptional balance between a high permeate flux (112.6 L m^–2 h^–1) and a superior retention efficiency (95%) for polystyrene microplastics (PSMPs). Mechanistic investigations reveal that the capture process is fundamentally driven by strong multisite hydrogen bonding and localized electrostatic attractions, which act as robust active chemical anchors. Furthermore, the aerogel demonstrates remarkable environmental resilience across diverse real-world freshwater matrices (86%–90% efficiency) and maintains outstanding continuous operational stability over 10 successive filtration cycles under high-loading conditions without requiring regeneration treatment. This work provides a highly scalable and structurally robust paradigm for designing advanced polymer aerogel filters, opening avenues for sustainable wastewater purification and microplastic pollution mitigation.