The Gemstone Honors Program at the University of Maryland is a unique multidisciplinary four-year research program for selected undergraduate honors students of all majors. This study represents the work of Team CATTAILS, a 2017 Senior Gemstone Team.
Oil spills pose a serious threat to aquatic life, the environment, and human health. Current methods to remove oil from waterways and mitigate damage include burning, skimming, and synthetic sorbents; however, they all have substantial limitations. Previous studies have shown that cattail (Typha spp.) fibers have potential as natural sorbents due to their hydrophobic and lipophilic properties. Additionally, cattail may be a more sustainable alternative than other natural sorbents including cotton. It is easily harvested, can be grown in a wide range of climates and has a smaller water footprint than cotton. The purpose of this study was to conduct a materials comparison between cattail fiber and other products such as cotton and rice hulls under varying water conditions for application as a sorbent during oil spill cleanup and remediation. Oil sorption of cattail and cotton was measured and expressed as gram-to-gram ratio of oil-to-fiber under a range of environmental conditions including water temperature and salinity.
Results/Conclusions
Overall, both cattail and cotton sorbed substantial amounts of oil. The average amount of oil retained was 26.39 ± 2.82 g g-1 for cattail fibers, 37.74 ± 3.34 g g-1 for cotton fibers and 4.54 ± 0.72 g g-1 for rice hulls. Cotton also sorbed greater amounts of water than cattail and the selectivity or ratio of oil to water absorbed was greater in cattail (5.6:1) than in Cotton (4.0:1). Oil sorption was reduced in both cattail and cotton at temperatures greater than 25 C and water sorption was concurrently increased in cattail. This reduced the selectivity of cattail from 5.6:1 to 4.8:1 suggesting that it would be less effective as a sorbant at warmer water temperatures. This could have been due to heat effects on the epidermal wax content of cattail rendering it less hydrophoebic in warmer water (> 25C) conditions. Water salinity alterted sorbance in some instances but did not have a definitive pattern. Of these three materials tested, cotton sorbed the most oil. However, cattail, because of higher selectivity (less water mass or volume sorbed per until mass or volumn of oil) and potential more sustainable production as a native perennial plant, offers an attractive alternative for additional research on ecologically sound mitigation strategies for oil spills in waterways.