writer：Duan-Chao Wang, Hou-Yong Yu, Xuemeng Fan, Jiping Gu, Shounuan Ye, Juming Yao, and Qing-Qing Ni
keywords：cellulose nanofiber, aerogel, physical crosslinking, mechanical properties, absorption?flocculants, copper ion adsorption
source：期刊
Issue time：2018年
Charged nanocellulose (NC) with high aspect ratio (larger than 100) extracted from animal or bacterial cellulose and chemical crosslinked NC aerogels have great promising applicability in material science, but facile fabrication of such NC aerogels from plant cellulose by physical crosslinking still remains a major challenge. In this work, carboxylated cellulose nanofiber (CNF) with highest aspect ratio of 144 was extracted from wasted ginger fibers by a simple one?step acid hydrolysis. Our approach could easily make the carboxylated CNF assemble into robust bulk aerogels with tunable densities and desirable shapes on a large scale (3D macropores to mesopores) by hydrogen bonds. Excitingly, these CNF aerogels had better compression mechanical properties (99.5 kPa at 80% strain) and high shape recovery. Moreover, the CNF aerogels had strong coagulation?flocculation ability (87.1%), removal efficiency of MB dye uptake (127.73 mg/g) and moderate Cu2+ absorption capacity (45.053 mg/g), which were due to assistance mechanisms of charge neutralization, network capture effect and chain bridging of high aspect ratio carboxylated CNF. This provided a novel physical crosslinking method to design robust aerogels with modulated networked structures to be a general substrate material for industrial applications such as superabsorbent, flocculation, oil?water separation, and potential electrical energy storage materials.