Isolation and characterisation of lignin from rice hull

Lignin was isolated from rice hull by dioxane acidolysis with concentrations of HCl in the solvent medium of 1.88, 3.76, 5.66, 7.56, or 11.40 g conc HCl litre −1 , and extraction times of 1 h and 2 h. Phenolic, methoxyl, and guaiacyl group contents were slightly low at 2 h of extraction, furthermore, at 2 h, the guaiacyl content of lignin extracted was reduced as the acid concentration was increased. The coniferyl group content was affected by acid concentration and extraction time. A maximum lignin yield was observed at the 5.66 g conc HCl litre −1 level and 2 h.