A highly hydrophobic polyhedral oligomeric silsesquioxane platform intended for microplastic adsorption and oil remediation

Abstract

The ubiquity and persistence of microplastics (MPs) and hydrophobic organic pollutants pose serious threats to aquatic environments and human health, necessitating the development of effective remediation strategies. In this study, a fluorine-free polyhedral oligomeric silsesquioxane (POSS) functionalized platform was successfully fabricated via a UV-assisted thiol–ene click reaction without any initiator. The platform contained both SH- and OV-POSS, which led to a sponge with durable superhydrophobicity, enhanced stability, and dual adsorption capability toward oils and microplastics. The structural and chemical features of the POSS modified sorbent were systematically confirmed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive spectroscopy (EDS), and Brunauer–Emmett–Teller (BET) surface area analysis. The modified platform by POSS features a highly interconnected porous structure and enhanced surface hydrophobicity (water contact angle: 153°). Kinetic and isotherm analyses demonstrate that the adsorption process follows a pseudo-second-order kinetic model and is best described by the Freundlich isotherm, indicating multilayer adsorption on heterogeneous surfaces. The modified platform rapidly adsorbed nearly 90% of MPs from aqueous suspension, maintaining high removal efficiency even after multiple reuse cycles. The POSS modified sponge also shows outstanding oil and organic solvent sorption capacities and retains its efficiency after performing multiple absorption/desorption cycles, and an absorption capacity of up to 89 g g⁻¹ for oil/organic solutions was achieved. Overall, the POSS-functionalized sponge proves to be a sustainable, efficient, and versatile platform for large-scale water treatment applications targeting both microplastics and oil pollution removal from aquatic media.