Different machined wood slices for separation of both oil/water mixtures and emulsions

Abstract

Tremendous efforts have been exerted to develop effective and ecofriendly materials for separation of oil/water mixtures and emulsions. However, porous materials with superwettability for oil/water separation are usually fabricated from nonrenewable precursors, which contradicts with the concept of green development. Inspired by the cellular porosity and hierarchical organization of wood, biodegradable cut and sawed wood slices with different pore sizes were separately machined by a razor blade and a fine-toothed saw. The cut and sawed slices separately possessed rough single- and double-layer structures. After silylation with MTCS, both machined slices repelled water entirely but allowed the complete permeation of oils. The fragment-free cut slice with relatively large pore size was able to separate immiscible oil/water mixtures, while the fragment-covered sawed slice with relatively small pore size could separate water-in-oil emulsions. Compared with other wood slice by sawing, the section structure and superoleophilic property made the slices have a high oil flux for a series of mixtures and emulsions, which reached 72 kL m−2 h−1 and 464 L m−2 h−1, respectively. The flux was high even after 10 cycles, exhibiting favorable recyclable stability.