Nanosecond laser fabrication of superwetting surface on Cu foam for oil-water separation and oil recovery

Abstract Oily wastewater has caused adverse affects on the ecology. In contrast, how to effectively treat the wastewater and recover oil has been a challenge. Herein, we proposed a facile and cost-effective method to solve the problem. A copper foam was fabricated by one-step nanosecond laser patterning for the first time and a superwetting surface was obtained. By adjusting ablation parameters, a superhydrophobic and superoleophilic surface was obtained whose water contact angle (WCA) was about 154.5° and oil contact angle (OCA) was 0° in air. In addition, surface morphology and elementary composition were characterized by scanning electron microscopy (SEM) and energy dispersive X-Ray (EDX) spectroscopy respectively. It is obvious hierarchical micro-nano structures were formed on the surface mainly caused by Cu melting and recasting during ablation. The ablated surfaces can be used not only for oil-water separation, but also for oil recovery with the recovery efficiency reaching 100%. Moreover, the surface exhibited outstanding stability which can be used for repeatable oil recovery application.