Underwater Superoleophobic Wood Cross Sections for Efficient Oil/Water Separation

Functional surfaces with specific wettability are widely encountered in nature and have inspired the development of oil-repellent materials for oil/water separation. Despite some impressive results reported, materials combining high separation efficiency together with economical and easily scalable approaches and ideally based on renewable resources have yet to be reported. In this Communication, spruce (Picea abies) wood cross sections are proposed as oil/water separation systems. The natural wood anisotropic porous microstructure directs fluid transport, and the nature of the cell wall biopolymers results in superhydrophilicity and underwater superoleophobicity. Such wood membranes can separate water from oil with high efficiency (>99%) and high flux using only gravity and without the need for prior chemical modification of the wood scaffold. Wood also provides an intrinsic solution to scalability issues.