Synthesis and Characterization of Acid-Activated Carbon Prepared from Sugarcane Bagasse for Furfural Production in Aqueous Media

Abstract

Furfural is a platform molecule obtained from hemicellulosic monosaccharides present in lignocellulosic biomass. Due to the possibility of converting this molecule into several value-added chemicals and the need to search for more sustainable production processes, the present work aimed to produce and characterize different sulfonated activated carbons (AC-S) from sugarcane bagasse (SCB) for application in furfural production in aqueous media. ACs were produced by chemical activation using salts of ZnCl2, NiCl2, and CuCl2 and a temperature and activation time of 550 °C and 3 h under nitrogen flow, respectively. Sulfonation was carried out with H2SO4 (98%) at a solid/liquid ratio of 1:10 at 160 °C for 2 h. Catalytic tests were performed using 5% catalyst mass regarding xylose, a temperature of 180 °C, and a reaction time of 2 h. ACs with high surface areas, ranging from 290 to 1100 m2 g−1, were produced. All catalysts had an increased sulfur content and total acidity after sulfonation, indicating the successful attachment of the sulfonic group (-SO3H) in the carbon matrix of the CAs. The AC-S/CuCl2 catalyst achieved the best catalytic performance compared to AC-S/ZnCl2, AC-S/NiCl2, and other acidic solids reported in the literature, achieving yield and selectivity of 55.96% and 83.93%, respectively. These results evidence the importance of the synergy between the Lewis and Brønsted acid sites on selective xylose dehydration and make AC-S/CuCl2 a promising acid catalyst for converting xylose to furfural in an aqueous medium.