Acid hydrolysis using concentrated mineral acids is currently the most applied method to prepare nanocellulose, specifically cellulose nanocrystals (CNCs). However, the method exhibits several critical defects, namely it is hazardous to the environment and human body, causes corrosion to the process equipment and the overdegradation of raw cellulose material, is high cost, and so on. Moreover, chemical modification to the functional groups of the CNC products is usually needed for further applications, also leading to extra costs. In this work, an innocuous weak acid (citric acid) was applied to prepare cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) from bleached bagasse pulp accompanied by simultaneous modifications of the functional groups on their molecular interface. It was discovered that with the small aid of ultrasonication at the appropriate preparation stage, citric acid could overcome the difficulties of hydrolyzing cellulose caused by its weak acidity, and CNCs were successfully produced with good nanoscales and high yield. CNCs with a diameter of 20–30 nm and length of 250–450 nm and CNFs with a diameter of 30–60 nm and length of 500–1000 nm were achieved. Up to 32.2% of the original bagasse pulp was converted to CNCs via citric acid hydrolysis with the assistance of ultrasonication, compared to only about 10.6% of the CNC yield without ultrasonication under the same hydrolysis conditions. At least one carboxylic group of the citric acid was simultaneously introduced to the cellulose via esterification during acid hydrolysis to form carboxylic CNCs and CNFs, which is important for further functionalization. Contents of carboxylic acid groups up to 0.65 mmol g⁻¹ for CNCs and 0.30 mmol g⁻¹ for CNFs were obtained, which endowed the CNCs and CNFs with highly stable dispersibility. Over 90% of the citric acid could be easily recovered through a rotary evaporator. The carboxylic CNCs and CNFs presented in this work offer commercial success and lower toxic risks, which means they have the potential to find applications as environmentally friendly, sustainable, and new bio-based nanomaterials in high-tech fields, such as biomaterials.

New functional cellulose/GO/TiO ₂ hydrogels are prepared via a simple method, showing superior and reproducible performance in the removal of MB.

As one of the most abundant natural polymers in nature, polysaccharides have the potential to replace petroleum-based polymers that are difficult to degrade in paper coatings. Polysaccharide molecules have a large number of hydroxyl groups that can bind strongly with paper fibers through hydrogen bonds. Chemical modification can also effectively improve the mechanical, barrier, and hydrophobic properties of polysaccharide-based coating layers and thus can further improve the related properties of coated paper. Polysaccharides can also give paper additional functional properties by dispersing and adhering functional fillers, e.g., conductive particles, catalytic particles or antimicrobial chemicals, onto paper surface. Based on these, this paper reviews the application of natural polysaccharides, such as cellulose, hemicellulose, starch, chitosan, and sodium alginate, and their derivatives in paper coatings. This paper analyzes the improvements and influences of chemical structures and properties of polysaccharides on the mechanical, barrier, and hydrophobic properties of coated paper. This paper also summarizes the researches where polysaccharides are used as the adhesives to adhere inorganic or functional fillers onto paper surface to endow paper with great surface properties or special functions such as conductivity, catalytic, antibiotic, and fluorescence.

Bacterial cellulose loaded with palladium was fabricated into a sheet-like dip-catalyst through compositing with plant fibers.