木聚糖碱抽提液超滤过程中的溶剂透过率

Solvent flux of the ultrafiltration of xylan alkali extractives

研究了从玉米芯碱抽提所得的木聚糖溶液在PS6超滤膜超滤过程中,溶剂透过率与主要操作参数间的关系.研究结果表明:在温度为25℃、进料速度ub为300mL/min、木聚糖质量浓度为20.0 g/L时,增加操作压力,通过PS6超滤膜的溶剂透过率随之增加,当压力为20～100 kPa时,溶剂透过率从4.9 L/(m2·h)增加到7.5 L/(m2·h);但是,当操作压力增加到120 kPa时,溶剂透过率不再随压力的变化而变化,维持在7.8 L/(m2·h);当温度为25℃、操作压力为150 kPa、木聚糖质量浓度为20.0 g/L时,溶剂透过率随着进料速度的增加而增加;进料速度对通过PS6超滤膜的溶剂透过率影响较小,当进料速度从200 mL/min增加到450 mL/min时,溶剂透过率从7.2 L/(m2·h)增加到8.7 L/(m2·h),仅增加20.8％;溶剂透过率与料液浓度间的关系符合膜模型,即j=K·ln(ρm/ρb).

Experimental study was carried out on ultrafiltration flux of xylan solution derived from alkali extraction of corncob through PS6 membrane. The results show that solvent flux is improved with the increase of operational pressure, under operational conditions of xylan concentration 20. 0 g/L, temperature 48 ℃, feed velocity 300 mL/min. Operational pressure increases from 20 kPa to 100 kPa, solvent flux is improved from 4. 9 L/(m2·h) to 7. 5 L/(m2 ·h). But the proper operational pressure should not exceed 120 kPa. Under operational conditions of xylan concentration 20. 0 g/L, temperature 48 ℃ , operational pressure 150 kPa, solvent flux is increases with enhanced feed velocity when ub increases from 200 mL/min to 450 mL/min, solvent flux increased by 20. 8%. Relation between feed concentration and solvent flux follows the membrane model.