溶液中木质素和葡萄糖的超滤分离

以木质素和葡萄糖的混合溶液为木质纤维素水解液模型,采用截留相对分子质量为5 000的卷式聚醚砜膜对葡萄糖和木质素进行全回流模式的分离,探讨了木质素和葡萄糖浓度、操作压力、错流速率对通量、木质素和葡萄糖截留率的影响。结果表明:在实验条件范围内,通量随葡萄糖浓度和木质素浓度的增加而降低,并随操作压力、错流速率的增加而增加。木质素截留率不受任何条件的影响,基本稳定在97%。葡萄糖截留率随木质素浓度的增加而增加,并随错流速率的增加而减小。在0.8 g/L的木质素质量浓度条件下,当错流速率从0.12 m/s增加到0.17 m/s时,葡萄糖截留率从14%减小到7.3%。由此可见,在混合溶液的超滤过程中,通过合理选择错流速率,能够改善木质素和葡萄糖的分离。

Separation of lignin and glucose in solutions by ultrafiltration

Solutions of lignin and glucose were used as models of lignocellulose hydrolysates, and the lignin and the glucose were separated using a spiral-wound polyethersulfone membrane with a molecular weight cut-off of 5 000.The effects of lignin concentration and glucose concentration,applied pressure and crossflow velocity on solution flux, lignin retention and glucose retention were discussed.Under the experimental conditions,the solution flux decreased with increasing of glucose concentration and lignin concentration, and increased with increasing of applied pressure and crossflow velocity.The lignin retention was almost constant at 97% .The glucose retention increased with increasing of lignin concentration, and decreased with increasing of crossflow velocity.Under the condition of a lignin concentration at 0.8 g/L,the glucose retention decreased from 14% to 7.3% when the crossflow velocity increased from 0.12 m/s to 0.17 m/s.A suitable crossflow velocity could improve the ultrafiltration separation of the lignin and the glucose.