Production of renewable phenols from corn cob using catalytic pyrolysis over self-derived activated carbons prepared with torrefaction pretreatment and chemical activation

The present work unveiled that the combination of chemical activation and torrefaction pretreatment was a promising approach for improving catalytic performance of activated carbon (AC) during conversion of corn cob into phenols. The characterization results demonstrated that P-containing functional groups (bands between 1000 and 1200 cm⁻¹) were imbedded into AC samples successfully. The increase in acid concentration and carbonization temperature could improve the porosity of as-prepared ACs. GC/MS results revealed that the selectivity of phenols was boosted (from 19.0% to 79.3%) during pyrolysis of corn cob over torrefaction pretreated AC catalyst. The high carbonization temperature (from 369 °C to 581 °C) and H₃PO₄ concentration (from 26.7% to 83.3%) favored the selectivity of phenols attained. The optimal condition for phenols selectivity (79.3%) was achieved at a carbonization temperature of 550 °C with H₃PO₄ concentration of 75%. The current study may provide an efficient pathway of converting agriculture waste corn cob into AC catalyst and phenols-enriched bio-oil, simultaneously, which will advance the utilization of renewable agriculture biomass.