Preparation of superhydrophobic/superoleophilic sugarcane bagasse-derived reduced graphene oxide anchored foam with application in oil/water separation

The conversion of bio-waste into carbon nanomaterials offers a sustainable and cost-effective approach to meet the growing demand for advanced functional materials and to treat the oil spill challenge in the massive water body. In this context, a sustainable, environment-friendly and efficient superhydrophobic/superoleophilic material is prepared by using sugarcane waste bagasse derived graphene oxide (GO) and functionalized to reduced graphene oxide (rGO) coated- polyurethane (PU) foam (rGO@PU) via a low-cost facile method for effective oil-water separation. The foam is dipped in the GO suspension followed by immersion in hydrazine hydrate to facilitate the reduction of GO to rGO. The scanning electron microscope (SEM) images illustrate the uniform deposition of rGO on the skeleton of PU foam. The rGO@PU foam shows a high repellency to water and affinity to various oil, with water contact angle (WCA) of 158.96° and oil contact angle of nearly 0°. Such non-wetting behaviour of the foam signifies the formation of Cassie-Baxter surface with low surface energy. Owing to its hierarchical pore structure, the adsorption capacities of rGO@PU foam for various oils are recorded in the range of 25-50 g/g. Furthermore, a demonstration is performed on the foam that successfully separated and recovered heavy oil like diesel and low oil like chloroform from the water. Hence, the GO/rGO@PU foam is evinced as an effective promising adsorbent material for oil spill cleanup.