活性炭吸附和TiO2光催化降解协同脱除杨木预水解液中木素的研究

Removal of Lignin from Poplar Pre-hydrolysis by Activated Carbon Adsorption Combined with TiO2 Photocatalytic degradation

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,木素脱除率为75.1%,总木糖得率为93.1%,糠醛脱除率为29.3%,5-HMF脱除率为22.4%,乙酸脱除率为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,木素的脱除率为40.2%,总木糖得率为89.0%,糠醛脱除率为24.2%,5-HMF脱除率为32.1%,乙酸脱除率为3.1%。活性炭协同TiO2光催化处理预水解液最优工艺条件为活性炭用量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 prehydrolysis liquid. Effect of activated carbon types (loganyl activated carbon activated carbon, food quality 303 activated carbon, coal activated carbon), activated carbon dosage, adsorption time, photocatalytic time, TiO2 dosage on the contents of lignin, total xylose, furfural, hydroxymethylfurfural(5-HMF) and acetic acid of prehydrolysis liquid were investgated. The treating conditions of activated carbon adsorption and TiO2 photocatalytic degradation were optimized. The results showed that effect of the wood-based phosphoric acid activated on lignin removal was best. Lignin removal of 75.1%, total xylose yield of 93.1 %, furfural removal of 29.3%, the 5-HMF removal of 22.4% and acetic acid removal of 3.5% were obtained at activated carbon dosage of 1.0% for 10 min. For single TiO2 photocatalytic degradation treatment, lignin removal of 40.2%, the total xylose yield of 89.0%, furfural removal of 24.2%, 5-HMF removal of 32.1% and acetic acid removal of 3.1% were achieved at TiO2 dosage of 1.0% for photocatalytic time of 10 h. The optimal treatmen conditions of activated carbon combined with TiO2 photocatalysis were 1.0% of activated carbon dosage, 0.1~0.5% of TiO2 dosage and 6 h of TiO2 photocatalysis, 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.