Silica-pyridine sulfonic acid catalyst for cellulose and glucose hydrolysis

Abstract

An innovative catalyst was developed for the purpose of simplifying the manufacturing process of biofuels without the need for costly materials. The incorporation of pyridine sulfonic acid (PSA) into silica rice husk (RH) was achieved by two distinct strategies, resulting in the production of a heterogeneous catalyst. The first catalyst, RHAPSA@Dir, was prepared using the Sol-Gel technique through a one-pot synthesis approach. The second catalyst, RHAPSA@Ref, was created through post-synthesis means. BET analysis of RHAPSA@Dir showed a significant improvement in surface area to 416 m2/g, while RHAPSA@Ref only exhibited 48.2 m2/g. Upon conducting elemental research on both catalysts, it was observed that the presence of carbon, nitrogen, and sulfur was apparent. The thermal study conducted indicated that approximately 47–48% of organic matter was lost from the silica at the anticipated temperature. The SEM analysis of RHAPSA@Dir revealed that a minor level of pore arrangement was observed. Furthermore, the TEM analysis of RHAPSA@Dir demonstrated that a few particles exhibited spherical nano shapes that were clearly visible. Conversely, the SEM analysis of RHAPSA@Ref showed a rough and porous surface with large particles. Lastly, the TEM micrograph of RHAPSA@Ref revealed spherical particles with an approximate diameter of 6 nm. The use of electron microscopy revealed the presence of spherical nanostructures. Both cellulose and glucose underwent hydrolyzation over the catalysts within 2–6 h at 140 °C. The essential properties of both catalysts were their stability and reusability.

Keywords

• Cellulose hydrolysis
• Glucose hydrolysis
• Pyridine sulfonic acid
• Rice husk
• Biofuel