Magnetic solid acid catalyst derived from different alkaline pretreatment of rice straw for hydrolysis of microcrystalline cellulose

Preparation of porous activated carbon (CK-Ar) through carbonization of extractive materials from alkali pretreated rice straw (RS) was developed as a precursor for the synthesis of sulfonated magnetic carbon (sMCK-Ar) to use as a solid acid catalyst. The physicochemical and morphological properties of CK-Ar, magnetic carbon (MCK-Ar), and sMCK-Ar samples were investigated with Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray, transmission electron microscopes, thermal gravimetric analysis, X-ray diffraction, and Brunauer-Emmet-Teller analysis. The acidic site density in sMCK-Ar was assessed using NH3- Temperature programmed desorption (NH3-TPH) method. Elemental CHNS analysis was used for the determination of the S density in the sulfonic samples. Also, vibrating-sample magnetometer analysis was used to determine the magnetic strength of sMCK-Ar. A porous soft structure with a surface area of 168.89 m(2)/ g and different acidic functional groups with a density of 3.97 mmol/g was observed for the sMCK-Ar sample. The influence of temperature (130, 150, and 170 degrees C), time (1, 2, 3, and 4 h), and the ratio of catalyst to the substrate (C/S) (0, 0.25, 0.5, and 1 g/g) were investigated on the hydrolysis performance of microcrystalline cellulose (MCC). Pretreatment with phosphoric acid converted cellulose. to cellulose II. Using the sMCK-Ar as a catalyst for the hydrolysis of pretreated microcrystalline cellulose in water caused the maximum total reducing sugars yield of 68.50%. Optimum reaction conditions were obtained at a C/S ratio of 0.25 g/g and 3 h at 130 degrees C for the sMCK-Ar catalyst.

Automated summary

A porous activated carbon (CK-Ar) was prepared from rice straw (RS) by carbonization of extractive materials and then used as a precursor for the synthesis of sulfonated magnetic carbon (sMCK-Ar) as a solid acid catalyst. The physicochemical and morphological properties of CK-Ar, magnetic carbon (MCK-Ar), and sMCK-Ar samples were investigated. The sMCK-Ar catalyst showed a porous soft structure with a high surface area and different acidic functional groups, and it exhibited good performance in the hydrolysis of microcrystalline cellulose.