Synthesis, characterization and acid catalysis of solid acid from peanut shell

Abstract A strong Bronsted solid acid was synthesized by sulfonation of the partially carbonized agricultural biowaste peanut shell. The acidity of the Bronsted solid acid was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectra (FT-IR) and solid-state nuclear magnetic resonance (NMR) spectroscopy. The characterization results show that sulfonation on the peanut shell carbon produces a carbon based solid acid containing three functional Bronsted acid sites: weak acidic OH groups, strong acidic COOH and SO 3 H groups. The acid strength of the solid acid is stronger than that of HZSM-5(Si/Al = 75), but still weaker than that of 100% H 2 SO 4 . The catalytic reaction tests indicate that this solid acid catalyst exhibits high activity and excellent recyclability for biodiesel production.