Study on structure and wetting characteristic of cattail fibers as natural materials for oil sorption.

Cattail fiber is considered as one of the biomasses for oil sorption purposes. In this work, the unique structure and wetting characteristic, as well as the basic mechanisms governing oil uptake of cattail fibers were investigated. Cattail fibers grow in tufts with down-like structure consisting of root, stem, seed and several fibers. A single cattail fiber was bamboo-shaped exhibiting 4-dimensional open spaces with fineness varying between 10 and 17.5 μm, average length at 7.9 ± 1.2 mm. The skeleton of the fiber consists of lignocellulose coated by a hydrophobic wax coating with 45.41% of crystallinity. The exceptional chemical, physical and microstructural properties enable the cattail fiber to be highly hydrophobic and oleophilic. The water droplets could stand on the fibers' surfaces with the contact angles more than 130°, while oil droplets disappear quickly from the fibers' surfaces within several seconds. When used as the sorbent for oil, cattail fibers were found to absorb about 12 g of oil per gram of fibers and retained over 88% of absorbed oil even after 24 h dripping. The unique structure of cattail fibers played an important role in oil sorption. The result proposed that cattail fibers are a promising natural source for the production of oil absorbents.