Abstract: Lignin was extracted from Camellia oleifera shell by alkaline water with the assistance of microwave. The effects of potassium hydroxide concentration, solid-to-liquid ratio, microwave power and treatment time on the yield of lignin were studied by single factor and orthogonal array design methods. Meanwhile, the lignin obtained was structurally analyzed by infrared and (IR) and UV spectroscopy. The optimum extraction conditions were as follows: alkaline concentration 0.7 mol/L, solid-to-liquid ratio 1:70, and microwave radiation power 550 W for an extraction duration of 60 min. Under such conditions, the yield of lignin was up to 11.45%. IR and UV spectral analyses showed that the lignin extracted by this method remained its original structure. In conclusion, the optimum microwave-assisted extraction technology for lignin from Camellia oleifera shell has been obtained, which has great significance for the comprehensive exploitation and industrial utilization of Camellia oleifera shell as a rich source of lignin.

Key words: lignin, microwave, alkaline, Camellia oleifera shell