Octaphenyl Polyhedral Oligomeric Silsesquioxane-Driven In Situ Growth of Corrosive-Resistant and Hydrophobic–Oleophilic ZIF-8 Nanostructures for Oil–Water Separation

The development of nanomaterials with hydrophobic–oleophilic surfaces that demonstrate exceptional durability and nontoxicity is essential for advancing self-cleaning technologies in challenging environments. Such materials play a critical role in efficient, continuous oil/water separation, effectively addressing the growing frequency of oil spills that threaten marine ecosystems and biodiversity. In contrast, many existing remediation materials contain toxic, bioaccumulative compounds, which pose significant risks to human health and other living organisms under both typical and extreme environmental conditions. To address environmental challenges, we have engineered a nanostructured Ph-POSS@ZIF-8 composite that offers exceptional stability, nontoxicity, and hydrophobic–oleophilic properties. This composite was synthesized via a simple, room-temperature in situ growth process, incorporating octaphenyl polyhedral oligomeric silsesquioxane (Ph-POSS) nanocage into hydrophilic zeolitic imidazolate framework-8 (ZIF-8). The Ph-POSS nanocage significantly enhances the hydrophobicity and oleophilicity of the composite, resulting in a material with a contact angle of 143 ± 2° and high absorption capacity for oils and organic solvents from their water mixtures. The Ph-POSS@ZIF-8@PDA@Sponge has shown impressive performance in oil and solvent separation, achieving over 90% efficiency for organic solvent–water mixtures and 80% efficiency for oil–water mixtures, even after 25 cycles. It maintains over 90% separation efficiency for hexane–water and chloroform–water mixtures under harsh conditions, with scanning electron microscopy (SEM) analysis confirming its structural integrity and durability in corrosive environments, attributed to the chemically inert POSS nanocage. Furthermore, the Ph-POSS@ZIF-8@PDA@cotton fiber exhibits superior antifouling properties, repelling water-based pollutants and removing coffee powder. It retains its hydrophobicity and mechanical stability, with only a slight loss in contact angle after physical deformation, and furthermore, it demonstrates exceptional absorption capacities and separation efficiencies. Density functional theory (DFT) calculations suggest that π···π interactions are the primary interactions between Ph-POSS nanocages and ZIF-8. This work highlights the nanomaterial’s potential to advance water purification and oily wastewater remediation, providing durable, self-cleaning, and high-performance corrosive environments for addressing oil pollution and wastewater management challenges.