Superhydrophobic PDMS@TiO2 wood for photocatalytic degradation and rapid oil-water separation

Natural wood, with its unique porous structure, has been widely modified for separating oil-water mixtures. However, the separation efficiency is often unsatisfactory, and little attention is focused on mitigating secondary pollution after its usable lifespan. Here, a superhydrophobic material consisting of delignified wood coated with titanium dioxide (TiO2) and polydimethylsiloxane (PDMS) was prepared. The resulting PDMS@TiO2 wood possessed outstanding superhydrophobicity, with a water contact angle of 160o. Owing to its longitudinal channels and excellent water repellency, the wood was successfully used to separate oil-water mixtures, with a high permeation flux of up to 6111 L·m−2·h−1 and separation efficiency of up to 93.4%. Importantly, PDMS and other oil pollutants were capable of being largely degraded after use via photocatalysis of the TiO2 layer, and the degradation reached 8.56 wt% within 30 days. The results from this study provide a method for fabricating functional superhydrophobic wood with photocatalytic degradation ability for efficient oily wastewater treatment.