Delignification of sugarcane bagasse with alkali and peracetic acid and characterization of the pulp

Abstract

Sugarcane bagasse was delignified with alkali and peracetic acid in a two-stage process to obtain pulps with high yield and low kappa number. The experimental results indicated that alkali pretreatment prior to peracetic acid (PAA) delignification could significantly reduce PAA loading by partially removing lignin and swelling the fibers. An optimum condition for the two-stage delignification was obtained for pulping of sugarcane bagasse. The pulps were further characterized by chemical composition analysis, strength property tests, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Thermal Gravimetric Analysis (TGA). It was found that the alkali-PAA process could be conducted under milder conditions with resulting higher pulping selectivity, higher degree of polymerization (DP), and superior mechanical properties of pulps, compared to the kraft pulping process. Both kraft pulps and alkali-PAA pulp had similar FTIR spectra, XRD spectra, and TGA (DTG) curves. However, further analysis indicated that the alkali-PAA pulp had higher infrared crystallization index and cellulose crystallinity.