rings that show a moderate affinity for oil adsorption, and polysaccharides (cellulose and hemicelluloses) composed of sugar units are capable of congealing oils after amphiphilic modification. Recently, some researchers have made attempts to convert lignin into attractive oil adsorbents. Rodrigues et al. prepared a magnetic oilabsorbing resin from lignin, cashew nut shell liquid, and formaldehyde by condensation reaction in the presence of nanomagnetite, demonstrating oil adsorption ability 11 g g −1 . [20] Wang et al. modified lignin with isocyanate in the organic solvent by the sol-gel method, and subsequently fabricated an ultralightweight, highly hydrophobic adsorption sponge through the impregnation adsorption process, whereby the oil absorption capacity could reach 217 times. [21,22] Pan et al. coated and grafted dopamine-reduced graphene oxide (rGO) and octadecylamine (ODA) on lignin-based polyurethane to prepare foam adsorbents with adsorption capacities far exceeding those of commercial nonwoven polypropylene adsorbents. [23] Notably, most of these lignin-derived oil adsorbents comprised a large amount of resin or inorganic compounds, while the lignin only takes a small part. [24,25] These bio-based oil adsorbents may face another problem as the Vander force between oil and adsorbent is weak, leading to poor oil adsorption capability. Recently, bio-based phaseselective organogelators capable of selectively congealing oil into floating gels in the presence of water emerged toward improving the adsorption performance. [26][27][28] In 2017, Sureshan et al. demonstrated a conceptually novel sorbent by impregnating cellulose pulp with a sugar-derived oleogelator, which could adsorb and congeal the oil concomitantly. [29] Then, by using biodegradable wheat bran as raw material, Ma et al. modified the hydroxyl groups of cellulose with vinyltriethoxysilane/SiO 2 particles to fabricate powdered gelator that selectively solidified the oil phase from an oil-water mixture at room temperature, as well as a maximum adsorption capacity of 6.15 g g −1 for motor oil. [30] In comparison to the traditional organogelators composed of small organic molecules, the exploration of biomass can avoid environmental damage. Cellulose derivatives have been well exploited as powder gelators, whereas the other components of lignocellulosic biomass, such as hemicelluloses, have been relatively little explored as oil spill agents. As the second most abundant renewable natural polymer, hemicelluloses account for 20-35% of lignocellulosic biomass, which has been estimated to be produced 15 million tons per annum from the USA pulp and paper industry. [31] Besides, the Despite rapid development, oil spill agents still suffer from limitations of high cost, low adsorption ability, and non-degradability. Herein, the alkaline lignin (AL) and hemicelluloses (xylan, Xyl) are transferred into low-cost, green, and eco-friendly powder gelators, featuring congealing oil ability, easy collection, and oil spill recovery. The AL and Xyl can form gels i...
