Ximing Zhang

Maleic acid (MA) and AlCl₃ self-assemble into catalytic complexes (Al–(MA)₂–(OH)₂(aq)) with improved selectivity for converting glucose to HMF, and levulinic acid.

A promising approach in the selective separation and modification of cellulose from raw biomass under a mild alkali process was proposed. In our study, ball milling was applied to wheat straw prior to alkali treatment. With ball milling, ultrafine powder formed an amorphous microstructure and displayed a level of solubilization in aqueous NaOH higher than that of general ground samples. Alkali-treated ultrafine powder resulted in up to 93.76% removal of hemicellulose and 86.14% removal of lignin, whereas cellulose remains largely undissolved. A high glucose yield (98.48%) was obtained via a 72 h enzymatic hydrolysis. X-ray diffraction and solid state 13C cross-polarization magic angle spinning nuclear magnetic resonance analysis revealed evidence of the transformation of crystalline cellulose I to cellulose II in alkali-treated ultrafine wheat straw. Prolonging the alkaline treatment time can significantly decrease the level of cellulose hydrogen bonding and increase the hydrolysis yield. The combination of ultrafine ball milling and low-severity alkali treatment played a significant role in the cellulose supramolecular change, which can then be used for downstream biorefinery processes or as a feedstock for the biomaterial industry.

Hierarchical structural carbon with properly modulated compositions and porosity is essential for energy storage capacity. Here, N-doped porous carbon was synthesized using abundant rice straw under the sequential hydrothermal treatment and calcination by KHCO3 in the presence of melamine. The activation with KHCO3 resulted in about a 50% increase in the yields of porous carbons and performance comparable to that of KOH. The extra additional melamine not only introduces the N-containing functional groups but also enhances the mesoporosity and specific surface area (2786.5 m2 g–1). Meanwhile, wettability and conductivity are improved. The obtained N-doped porous carbon exhibits outstanding capacitance of 317 F g–1 at 1 A g–1. The fabricated symmetric supercapacitor displays a stable cycling performance (99.4% retention after 5000 cycles), a reasonable rate performance, and the maximum specific energy of 18.4 W h kg–1. Our research provides a promising method for effectively converting biowaste into energy storage materials through green synthetic strategy.