Modified Cotton Sponge with Bio-Based Polybenzoxazine for Plasticizer Absorption and Oil–Water Separation

Plastic pollution in the marine environment and oily wastewater generated in industry are now recognized as a real threat, as they adversely affect the environment and cause health issues to living organisms as well. Nevertheless, the current methods for both oil/water separation and plasticizer removal are complex and costly. In this regard, a low-cost and environment-friendly superhydrophobic/superoleophilic material has been developed. Cotton sponge (CS) coated with polybenzoxazine (Pbz) and stearic acid-functionalized carbon balls (CBS) [i.e., CS-Pbz-CBS] acts as a superhydrophobic/oleophilic material. By employing surface modification of CS with Pbz-CBS, the hydrophilic CS gets transformed into superhydrophobic CS-Pbz-CBS possessing a water contact angle of 153°. A surface morphological study indicated the selective wettability produced by CS-Pbz-CBS materials as a result of tuning their surface composition and surface roughness as well. In addition to it, the prepared material CS-Pbz-CBS (6%) also possesses excellent mechanical durability, exhibits fast and efficient separation of oil–water mixtures, and can act as an effective material for plasticizer removal. Moreover, the prepared material, CS-Pbz-CBS (6%), has a volumetric absorption capacity, Qw(v/v), of 83.51 for CHCl3 and provides a 95% separation efficiency for oil/water mixtures. The detailed investigation related to the preparation of these materials and their applicability in oil/water separation and plasticizer removal is analyzed.