Tailoring Carbon Nanostructure for Selective Guar Gum Conversion: Unveiling the Interplay between Structure and Surface Functionalities in Galactose and Mannose Production

Abstract

To acquire galactose and mannose, the food and pharmaceutical industries can benefit greatly from the efficient catalytic hydrolysis of the glycosidic linkage in the galactomannan bond found in guar gum. Through surface functionalities and structural characteristics, in this work, we found that an amorphous carbon catalyst functionalized with chlorine and carboxylic acid has glycosidic bond hydrolysis ability. The yield of galactose and mannose is increased by an increase in chlorine functionalities and the amorphous nature of carbon, confirmed by detailed surface advance characterization techniques such as X-ray photoelectron spectroscopy and Raman spectroscopy. The catalyst’s chlorine functionality provides binding sites and allows the guar gum to interact with carboxylic acid, active sites. At 200 °C for 1.5 h, a high selectivity of 90% for mannose and galactose is achieved. The activated carbon treated with aqua regia exhibits excellent activity and stability for up to four cycles.