| Abstract:Activated carbon adsorption and TiO2 photocatalytic degradation were used for removing lignin from poplar prehydrolyzate. Effect of activated carbon types (wood-based phosphoric acid activated carbon, food quality 303 activated carbon, coal-based activated carbon), activated carbon dosage, adsorption time, photocatalytic time, TiO2 dosage on the contents of lignin, total xylose yield, furfural, hydroxymethylfurfural(5-HMF) and acetic acid of prehydrolysis liquid were investgated. The conditions of activated carbon adsorption and TiO2 photocatalytic degradation were optimized. The results showed that the adsorption effect of wood-based phosphoric acid activated carbon on lignin removal was the best. Total xylose yield of 93.1%, the lignin, furfural, 5-HMF, and acetic acid removal rates of 75.1%, 29.3%, 22.4%, and 3.5% respectively, were obtained when activated carbon dosage was 1.0% and adsorption time was 10 min. For single TiO2 photocatalytic degradation treatment, the total xylose yield of 89.0%, the lignin, furfural, 5-HMF, and acetic acid removal rates of 40.2%, 24.2%, 32.1%, and 3.1% , respectively were achieved when TiO2 dosage was 1.0% and photocatalytic time was 10 h. The optimal treatment conditions of combining activated carbon adsorption and TiO2 photocatalysis of prehydrolyzed liquid were dosage 1.0% of wood-based phosphoric activated carbon, photocatalytic time for 6 h and TiO2 dosage of 0.1%~0.5%, in which 84.4%~86.7% of lignin removal, 88.2%~89.8% of total xylose yield, 53.8%~65.1% of furfural removal, 48.6%~51.7% of 5-HMF removal were obtained, and acetic acid content was not obviously changed. |
