Study on Oil–Water Separation Performance of PDA/ODA Composite–Modified Sponge

The study involved the modification of a melamine sponge (SP) through the introduction of polydopamine (PDA) and octadecylamine (ODA), resulting in the creation of three distinct sponge types: PDA/ODA@SP, PDA@SP and ODA@SP. The successful modification of PDA and ODA onto the surface of the sponge was confirmed through the utilisation of scanning electron microscopy and x-ray photoelectron spectroscopy. Consequently, the resulting sponges exhibited a unique micro–nano composite structure. Wettability testing was conducted to assess the properties of the sponges, revealing that the PDA/ODA@SP sponge demonstrated hydrophobic superlipophilic characteristics. Moreover, a series of 10 repeated oil–water separation experiments indicated that the PDA/ODA@SP sponge achieved an impressive separation efficiency of up to 97%, demonstrating its exceptional oil–water separation capabilities and reusability. Additionally, investigations utilising soybean oil and engine oil demonstrated the composite sponge's superior absorption capabilities for fatty acids and hydrocarbons.