High Aspect Ratio Carboxylated Cellulose Nanofibers Cross-linked to Robust Aerogels for Superabsorption–Flocculants: Paving Way from Nanoscale to Macroscale

Abstract

Charged nanocellulose (NC) with a high aspect ratio (larger than 100) extracted from animal or bacterial cellulose and chemical cross-linked NC aerogels have great promising applicability in material science, but facile fabrication of such NC aerogels from plant cellulose by physical cross-linking still remains a major challenge. In this work, carboxylated cellulose nanofiber (CNF) with the 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 Cu 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 cross-linking 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.

Water Soluble Polymer Flocculants: Synthesis, Characterization, and Performance Assessment

“…Typically, chemical or physical cross‐linking (ionic interactions, entanglements) routes are employed to induce effective entanglements between individual nanocellulose fibers to fabricate high‐performance nanocellulose‐based aerogels . In a novel attempt of preparing cellulose‐based aerogel, Wang and coworkers extracted carboxylated cellulose nanofibers from waste ginger using one‐step acid hydrolysis and formed robust bulk aerogels by hydrogen bonding . The highest aspect ratio of 144 led to the formation of physically cross‐linked/entangled ultra‐lightweight and robust aerogels via strong interfacial adhesion (hydrogen bonds) without any external chemical modifications.…”

“…Extraction of cellulose nanofibers from ginger, formation of aerogel by acid hydrolysis, and coagulation–flocculation performance in kaolin and methylene blue suspensions. Reproduced with permission . Copyright 2018, American Chemical Society.…”

“…[81] In a novel attempt of preparing cellulose-based aerogel, Wang and coworkers extracted carboxylated cellulose nanofibers from waste ginger using one-step acid hydrolysis and formed robust bulk aerogels by hydrogen bonding. [82] The highest aspect ratio of 144 led to the formation of physically cross-linked/entangled ultralightweight and robust aerogels via strong interfacial adhesion (hydrogen bonds) without any external chemical modifications. Moreover, these aerogels had low density, high porosity, the ability to absorb 476 times their own mass of water, and better compression performance.…”

“…Microwave-based grafting can be classified into two types: microwave-initiated synthesis (using microwave radiation alone to initiate grafting) or microwave-assisted synthesis (combining microwave radiation and Reproduced with permission. [82] Copyright 2018, American Chemical Society. Figure 15.…”

Preparation, Characterization, and In Vitro Evaluation of Resveratrol-Loaded Cellulose Aerogel

“…For example, cellulose aerogel has been used as a catalyst or a catalyst matrix, which can provide a stable network structure, and particles were dispersed uniformly without aggregation [14]. Cellulose aerogels can also be used as an amphiphilic superabsorbent, which is a good choice for wastewater clarification [15,16]. Recently, the application potential of cellulose has also been gradually studied in the field of biomedicine.…”