Switchgrass as oil and water-spill sorbent: Effect of particle size, torrefaction, and regeneration methods

Switchgrass, both raw and torrefied, was tested for its ability to sorb water or oil. The cyclic performance was also examined, utilizing centrifugal extraction as the regeneration method. Both oil and water sorption capacity increase with the decreasing size of raw switchgrass particles. Results indicate that 3 mm raw switchgrass can sorb water at a capacity of about 6 times its mass and can sorb oil at a capacity of about 3 times its mass, which makes it a suitable biodegradable sorbent. Torrefaction at 220 °C for 30 min reduces water sorption capacity by an average of 55% but does not have a statistically significant impact on oil sorption. Sorption of liquid is negatively correlated to particle size. Centrifugation is able to partially desorb either liquid from the sorbent, and subsequent sorption cycles do not display lower sorption capacity than the first cycle when calculated on a dry mass basis.