Cotton Nonwovens as Oil Spill Cleanup Sorbents

We examined partial or complete replacement of synthetic sorbents by cotton- containing nonwovens for use in oil spill cleanup. The results indicate that with light crude oil, oil sorption capacities of the needlepunched cotton-containing sorbents were slightly greater than those of sorbents made from 100% polypropylene fibers. If necessary, a small portion of polypropylene fiber could be incorporated into nonwovens to increase mechanical strength properties and to maintain fabric integrity. The cotton- containing sorbents were reusable after a simple mechanical compression to remove oil. They also floated in an artificial seawater bath for a long period of time. We found that oil sorption of cotton fiber was controlled by adsorption on the fiber surface and capillary action through its lumen. Contrarily, the main mechanism for polypropylene was through capillary bridges between fibers. Detailed evaluation using an environ mental scanning electron microscope confirmed this mechanism. Individual bundles of both cotton and polypropylene fibers sorbed more oil than did the needlepunched nonwoven fabrics prepared from the respective fibers. In addition, sorption decreased as needling density increased. This study provides preliminary data for investigating other cotton nonwoven constructions with improved oil sorption properties.