Extraction of cellulose nanocrystals using acid-periodate sequential processing from furfural residue
摘要
Furfural residue (FR), a major lignocellulosic byproduct of industrial furfural production, poses significant environmental challenges due to its disposal via landfilling or incineration. To valorize this underutilized resource, this study presented a sequential acid-periodate approach for extracting dialdehyde-functionalized cellulose nanocrystals (FR-DCNC) from FR. The process initiates with efficient delignification using formic acid/hydrogen peroxide (FA/H2O2) pretreatment, yielding purified cellulose (FR-C) with minimal lignin content. Subsequent sulfuric acid hydrolysis liberated cellulose nanocrystals, which were selectively oxidized by sodium periodate to introduce aldehyde functionalities via C2-C3 bond cleavage. Comprehensive characterization revealed that FR-DCNC exhibited high crystallinity (78.6%), a rod-like morphology (diameter = 12.6 nm), and an exceptionally high specific surface area (289 m2/g). FTIR confirmed successful dialdehyde formation while thermogravimetric analysis demonstrated enhanced thermal stability (Tmax=221 °C) compared to raw FR. The introduced aldehyde groups (2.6 mmol/g) endow FR-DCNC with high surface reactivity for advanced applications in polymer composites, adsorption, and functional materials. This work establishes a sustainable pathway to transform industrial biowaste into high-value functional nanomaterials, aligning with circular economy principles.