Lignin/Xylan‐Based Phase Selective Powder Gelator for Eco‐Friendly Oil Spill Treatment

Abstract

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...

Aluminum soap nanoparticles-lignin powder form phase-selective gelator: synergistic adsorption and gelation for rapid oil spill recovery

“…Filtered, dried in a vacuum oven at 60 °C for 12 h to obtain solid pieces, and then the solid pieces were ground into powder form samples. The samples were denoted as AL/Al HSA-x (x is the weight percent of added ECH) (Wang et al 2021).…”

“…The broader peaks at 3200−3600 cm -1 were attributed to −OH stretching vibration (Dai et al 2019). After OTS modification, the new small band at 919 cm -1 was attributed to Si−C and Si−O−C at 1192 cm -1 (928 and 1182 cm -1 in OTS-AL/Al HSA-45, respectively), indicating that the hydroxyl groups of lignin were coupled with OTS (Kumar et al 2017;Wang et al 2021).…”

“…Lignin is an abundant biomolecule in nature, degradable and biocompatible with many reactive functional groups such as aromatic, hydroxy, and methoxy groups. In particular, lignin comprises hydroxyl units that could be irregularly coupled with biomacromolecules (e.g., xylan) to make multiperformance composites (Wang et al 2021). Therefore, in our study, we proposed to combine lignin with Al HSA (Scheme.…”