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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 (TiO 2) and polydimethylsiloxane (PDMS) was prepared. The resulting PDMS@TiO 2 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 TiO 2 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. [Display omitted] • A new strategy for fabricating superhydrophobic wood with anisotropic porous structure is reported. • The wood presents excellent separation flux in oil-water separation. • The wood exhibits great photocatalytic degradation ability for post-treatment. [ABSTRACT FROM AUTHOR]

Superhydrophobic materials possess prospective applications of oily wastewater treatment due to their high efficiency and easy operation. Nevertheless, most superhydrophobic materials are difficult to separate oil-water emulsion, especially for highly viscous water-in-crude oil emulsion. Herein, a superhydrophobic wood with excellent Joule heat and demulsification was proposed by chemically treating the natural wood and subsequent coating of the carboxyl-modified carbon nanotubes (cCNTs) for providing conductive pathways, polyethylenimide (PEI) for supporting demulsification and polydimethylsiloxane (PDMS) for hydrophobic modification. The fabricated superhydrophobic PDMS@PEI-cCNTs wood displayed a water contact angle of 155o and great compression property with a nearly undamaged structure at a strain of 40 % after 50 compression tests, which could separate and recover oil from the oil-water mixture via absorption-extrusion process. Besides, due to the filtration and electrostatic interaction of the PDMS@PEI-cCNTs wood, the water-in-oil emulsion was demulsified quickly with a separation efficiency greater than 99.7 %. Meanwhile, the PDMS@PEI-cCNTs wood showed a good Joule heat capability, and the surface temperature reached 160 °C at 35 V of voltage within 120 s, which largely reduced the viscosity of water-in-crude oil emulsion. Thus, the PDMS@PEI-cCNTs wood was successful in separating the water-in-crude oil emulsion via Joule heat capability with a separation rate of 4.33 × 104 kg·m−3·h−1 and a separation efficiency of 93.4 %. The material developed in this study has wide range of applications in treating the stable crude oil-water emulsion with high viscosity. [Display omitted] • A new strategy for fabricating superhydrophobic wood for various oil-water emulsions separation is proposed. • The wood presents stable superhydrophobicity and good electrical conductivity. • The wood shows excellent demulsification capability via charge action, absorption and gathering. • The wood exhibits great Joule heat to promote separating viscous water-in-crude oil emulsion. [ABSTRACT FROM AUTHOR]