Facile preparation of Cucurbit[6]uril modified melamine sponge for efficient oil spill cleanup

Herein, as a part of a circular economy, we have utilized Cucurbit[6]uril CB6 (a major product formed during the synthesis of CBn), to convert commercial hydrophilic melamine sponge (MS) into hydrophobic CB6 coated melamine sponge (abbreviated as CB6@MS). A facile, cost-effective, and rapid one-step dip-coating method without using the toxic and expensive modifying agents for the preparation of CB6@MS at ambient conditions is described. The prepared modified sponge is characterized using Fe-SEM, FT-IR, TGA, and PXRD. Self-assembly of CB6 on the skeleton of MS by hydrogen bonding/electrostatic interactions enhanced MS surface roughness and improved MS stability by maintaining its original 3D porous structure. The CB6@MS hydrophobic sponge had excellent oil absorption potential for many oils and organic solvents (53-112 g/g). The absorbed oil or solvents could be recycled in the simple squeezing process because of structural stability and strong elasticity of CB6@MS sponge, and absorption performance was nearly unchangeable after 15 absorptions/squeezing cycles. The resultant sponge can also continuously absorb and extract oil from the pollutant water through a vacuum pump. Thus, the utilization of the major undesired product, simple preparation, economical, and excellent oil separation would give this approach great potential to develop various CB-based applied materials.