Recycling waste epoxy resin as hydrophobic coating of melamine foam for high-efficiency oil absorption

The preparation of oil absorption materials with both low-cost and high efficiency remains a great challenge. In this work, a waste epoxy resins (EPs) derived hydrophobic modifier was developed to fabricate high-efficient oil absorbents by simple dip-coating on melamine foam (MF). EPs were effectively degraded by acid digestion in mild condition to obtain the degradation products (DEPs) with a large molecular weight. DEPs can be directly used as a hydrophobic agent due to excellent hydrophobicity and processability. The resulting DEPs@MF exhibited excellent absorption performance for various oils or organic solvents with an ultrafast adsorption rate of 2 s and high oil absorption capacity of 116 g g(-1). Moreover, the absorbed oils can be recovered by simple mechanical extrusion, and the adsorption capacity of the DEPs@MF did not deteriorate even after it was reused for 10 times. Besides, an oil recovery unit was successfully designed to achieve continuous oil-water separation. This research not only provides a new approach to the preparation of highly efficient and reusable oil-absorbing materials, but also provides new insight into solving the increasingly serious problem of waste thermosetting polymers.