Preparation And Characterization Of Oil Sorbents From Populus Fibers

Oil spillage does not only lead to the loss of non-renewable resources, but also threatens the health of marine creatures and human beings. Sorption via modified biomass sorbents is the most popular treatment technology due to its low cost and efficiency. Among chemical modification methods, acetylation and surface modification have been widely studied for oil removal. However, many crucial obstacles should be overcome due to the expensive and toxic reagents used in acetylation and the non-biodegradability of the inorganic mineral coating. To overcome these obstacles, the common and representative Populus fibers were modified through hydrothermal treatment or coated with acetylated technical lignin.The optimum conditions of the hydrothermal treatment and acetylation were obtained at 170℃ for 1 h and 120℃for 2 h, respectively. The maximum oil sorption capacity (OSC) of the hydrolyzed fiber (16.78 g/g) was slightly lower than that of the acetylated fiber (21.57 g/g), but they were both higher than the maximum OSC of the unmodified fiber (3.94 g/g). In addition, acetylation after hydrothermal treatment for the Populus fiber was unnecessary as the increment of the maximum OSC was only 3.53 g/g. The hydrolyzed and the acetylated Populus fibers both displayed a lumen orifice enabling a high oil entrapment. The use of hydrothermal treatment instead of acetylation is advantageous because of obtaining an adequate OSC as well as characteristics of economy and environmental compatibility.Populus fibers were soaked in acetone solutions with different concentrations of acetylated lignin to prepare oil sorbents under ultrasonic treatment. The OSC of the acetylated lignin-coated sorbent (18.35 g/g,2% lignin concentration) was 4.7 times higher than that of the uncoated fiber, and was higher than that of hydrolyzed fiber. More importantly, the proposed sorbent showed a high level of recyclability (14.70 g/g) even after four cycles; the adsorbed oil was able to be rapidly recovered by a simple squeezing process. The coated samples showed a good hydrophobicity with water contact-angle (WCA) values all over 120°, the biggest WCAof 152.3° has reached the superhydrophobic leveL So, the acetylated lignin is a favorable potential coating for materials which show high capacity, porosity, and low density to improve their oil/water selectivity.