ABSTRACT
A sustainable nanomaterial, cellulose nanofibril (CNF) was used to prepare aerogel sorbents to remove various contaminants in wastewater. A mussel-inspired coating strategy was used to introduce polydopamine onto the surface of CNFs, which were cross-linked with polyethylenimine (PEI) to form the aerogels. The synthetic procedure was optimized to achieve a minimal consumption of raw materials to produce a robust porous structure. The aerogels possessed a low density (25.0 mg/cm3), high porosity (98.5%) and shape recovery in air and water. Adsorption studies were conducted on two representative contaminants, Cu (II) and methyl orange (MO). The kinetic data obeyed the pseudo 2nd order kinetic model and the mechanism of adsorption could be described by the intra-particle diffusion model. The Langmuir model fitting yielded a maximum adsorption capacity of 103.5 mg/g and 265.9 mg/g for Cu (II) and MO, respectively. The effects of pH on the adsorption performance were evaluated, confirming that the aerogels can maintain a high adsorption capacity over a wide pH range.
ABSTRACT
Sulfated cellulose nanocrystals (CNC) with high surface charge density are inadequate for stabilizing oil-water emulsions, which limits their applications as interfacial stabilizers. We performed end-group modification by introducing hydrophobic chains (polystyrene) to CNC. Results showed that the modified CNC are more effective in emulsifying toluene and hexadecane than pristine CNC. Various parameters were investigated, such as concentration of particles, electrolytes, and polarity of solvents on the characteristics of the emulsions. This study provides strategies for the modification of cellulose nanocrystals to yield amphiphilic nanoparticles that enhance the stability of emulsions. Such systems, bearing biocompatible and environmentally friendly characteristics, are attractive for use in a wide range of industries spanning food, biomedicine, pharmaceuticals, cosmetics, and petrochemicals.
