Preparation of carbon-based solid acid catalyst from rice straw for furfural production in aqueous media

A powerful carbon-based solid acid catalyst and furfural were obtained from rice straw (RS) biomass resource. The acid catalyst was prepared through the carbonization and sulfonation of RS. Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, N2 adsorption-desorption, and ammonia temperature-programmed desorption (NH3-TPD) were used to characterize the catalysts. The effect of sulfonation time (4 h to 16 h) on the structure and acidity of the catalysts was elucidated. After 16 h of sulfonation, the BET surface area and the total acidity of the catalyst reached 415 m2/g and 7.48 mmol/g, respectively. Moreover, strong acid sites accounted for more than 63% of acidity. The catalyst was then used for the conversion of RS into furfural in water. The influence of reaction temperature and time while using the catalyst on the conversion process was also investigated. The catalyst exhibited high activity in the conversion of RS, with a furfural yield of 68.3 g/kg RS at 160 °C in 5 h.