Superhydrophobic STA@PF@Cu2O modified wood with photocatalytic degradation properties for efficiency oil/water separation

The potential for coatings using Cu2O nanostructures combined with stearic acid (STA) and phenol formaldehyde (PF) resin to selectively sorb oils from oil/water mixtures was explored on balsa wood (Ochroma pyramidale). Wood samples coated by immersion in [email protected]@Cu2O nanostructures absorbed 1.6–3.9 times their weight from a wide range of oil and organic solvents with absorption capacity generally increasing with oil density. Separation efficiency of the coated balsa was above 90% for several oil/water mixtures, and the material surface could be regenerated up to 30 times by exposure to visible light while still retaining up to ~94% efficiency. For example, a 320 min light exposure of coated samples used to sorb methylene blue resulted in 99.8% degradation with photocatalytic reaction rate constants reaching 0.013 min–1. The coating represents an easily applied, cost effective and efficient system for oil sorption or oil/water sorption for spill-cleanup or wastewater treatment.