Separation of lignin from biomass using acidic heterogeneous catalysts

Abstract

This research studied the separation of lignin with heterogeneous catalysts. The effects of parameters for lignin separation such as types of catalysts, reaction temperature, time and ethanol to deionized water ratio were investigated. The result showed that lignin separation was achieved by using Amberlyst-15 at 200◦C for 30 min with EtOH:water (80:20 v/v) in pressure Parr reactor equipment. The result illustrated that the isolated lignin from giant sensitive plant by preatreatment with 1 wt% of H2SO4 pretreatment and from corncob were 16.83% and 11.60%, respectively. Then, the isolated lignin from both plants were purified with Klason method that showed lignin purity as 95.77% and 72.49%, respectively. The structure of isolated lignin and Klason lignin from both two samples were confirmed by Fourier transform infrared spectroscopy (FTIR), proton-1 Nuclear Magnetic Resonance Spectroscopy (1H NMR), carbon-13 Nuclear Magnetic Resonance Spectroscopy (13C NMR) and C, H, O, N analyzer. In addition, the morphological structure and thermal degradation were characterized by scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The isolated lignin, Klason lignin from giant sensitive plant and corncob were pyrolysized with ZSM-5 at 300◦C for 30 min. The results illustrated the high product selectivity of 1,2,4-trimethoxybenzene (14.5-15.4%) and catechol (26.6-30.3%), respectively.