Mild acid batch conversion of corncob biomass to furfural: Toward circular bioenergy and global research trends.

Corncob biomass, a hemicellulose-rich agricultural residue, is a promising feedstock for furfural, a renewable platform chemical for biofuels, resins, and green solvents. This study presents a proof-of-concept batch process using low-concentration sulfuric acid under moderate conditions, aligned with circular bioeconomy goals. Corncob was pretreated (100 mesh, 8.8 % moisture) and reacted at 150 °C, 4 bar, 30 min with 1-3 % HSO. Furfural was extracted with toluene and purified, then verified by HPLC, FTIR, SEM, and GC-MS. The maximum yield was 1.524 % (w/w, dry basis) at 3 % acid, consistent with enhanced xylan hydrolysis. However, the use of toluene raises environmental concerns, highlighting the need to evaluate greener solvents such as 2-methyltetrahydrofuran or deep eutectic solvents. Although energy input was not measured directly, the moderate temperature and short reaction time suggest reduced energy intensity compared with conventional hydrothermal methods, while the batch setup provides a scalable and modular platform for decentralized biorefineries. A bibliometric analysis (VOSviewer) contextualized the findings, revealing exponential publication growth, active international collaborations, and research gaps in green solvents, catalyst recycling, kinetic modeling, and system integration. This study offers both technical insights and strategic direction for sustainable furfural production from agricultural waste within a circular bioeconomy framework.