活性炭吸附结合TiO2光催化分离纯化杨木预水解液中的木糖

Purification of Xylose in Poplar Prehydrolyzate by Activated Carbon Absorption Combined with TiO2 Photocatalysis

关键词:  杨木  预水解液  活性炭  TiO₂光催化  木素脱除

Key Words:poplar  prehydrolyzed liquid  activated carbon  TiO₂ photocatalysis  lignin removal

摘要:利用活性炭吸附和TiO₂光催化降解脱除杨木预水解液中的溶解木素，探讨了不同活性炭类型（木质基磷酸活化活性炭、食品质303活性炭、煤质活性炭）、活性炭用量、吸附时间、光催化时间、TiO₂用量对预水解液中木素、总木糖、糠醛、羟甲基糠醛（5-HMF）以及乙酸等有机组分含量的影响，优化确定了活性炭吸附和TiO₂光催化降解条件。研究结果表明，木质基磷酸活化活性炭对木素的吸附脱除效果最好，在活性炭用量为1.0%和吸附时间为10 min时，总木糖得率为93.1%，木素、糠醛、5-HMF、乙酸脱除率分别为75.1%、29.3%、22.4%、3.5%。单一TiO₂光催化处理，在TiO₂用量1.0%和光催化时间10 h条件下，总木糖得率为89.0%，木素、糠醛、5-HMF、乙酸脱除率分别为40.2%、24.2%、32.1%、3.1%。活性炭协同TiO₂光催化处理预水解液的较优工艺条件为：木质基磷酸活化活性炭用量1.0%、光催化时间6 h和TiO₂用量0.1%~0.5%，此条件下预水解液中木素的脱除率为84.4%~86.7%，总木糖得率为88.2%~89.8%，糠醛脱除率为53.8%~65.1%，5-HMF脱除率为48.6%~51.7%，乙酸含量变化不明显 。

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.