秸秆低聚木糖溶液纳滤分离特性和渗滤工艺  

Separation performance of xylo-oligosaccharides from wheat straw using nanofiltration membrance and technology for diafiltration

作　　者：赵鹤飞[1] 杨瑞金[2] 赵伟[1] 卢蓉蓉[2] 张文斌[2] 

机构地区：[1]江南大学食品科学与技术国家重点实验室,无锡214122 [2]江南大学食品学院,无锡214122

出　　处：《农业工程学报》2009年第4期253-259,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家"十一五"科技支撑计划项目"食品冷加工及高效分离技术(2006BAD05A02)";"食品功能因子高效分离与制备关键技术的研究(20060BAD27B03)"

摘　　要：该文研究了截留相对分子质量为250的纳滤膜分离以秸秆为原料生产的低聚木糖溶液的分离特性,并优化了渗滤纯化工艺。通过检测透过液和截留液中各糖组分的浓度,计算并得到了该膜对阿拉伯糖、木糖和聚合度(Degree of Polymerization)DP2到DP4的低聚木糖的截留率随膜通量变化的关系曲线;应用不可逆热力学模型对阿拉伯糖、木糖和DP2到DP4的低聚木糖中性溶质体系的截留率试验数据进行回归计算,求得了反射系数、溶质透过系数和水透过系数等膜分离特性参数,并根据立体位阻模型估算出膜的细孔结构参数。当糖液浓度为8.4%(总糖/糖浆),膜系统温度控制在(30.1±2.1)℃,跨膜压差控制在(1.58±0.02)×106Pa的恒定体积渗滤操作模式下,膜通量无衰减,稳定在(29.4±1.8)L/(m2·h),经3倍体积纳滤渗滤操作后,低聚木糖纯度由原料的83.33%(DP2到DP6低聚木糖/总糖)上升至92.54%,木二糖损失率为12.45%(对原料中的木二糖),总糖回收率为88.39%(对原料中的总糖)。纳滤分离模型的研究为低聚木糖溶液的渗滤纯化和浓缩模拟并精确优化工艺提供了参数基础,使用纳滤膜在渗滤操作模式下,可以高效脱除单分子糖,同时低聚木糖损失较小。Separation performance and purification of xylo-oligosaccharides （XOs） solution derived from wheat straw by a nanofiltration（NF） membrane with a molecular weight cut-offs （MWCO） of 250 were investigated. The profiles of rejections of the arabinose, xylose and XOs with degree of polymerization （DP） from two to four at different membrane fluxes were obtained based on the detection of their concentrations in filtrate and retention. According to irreversible thermodynamics model, reflection coefficient, solute permeability, solution hydraulic permeability of arabinose, xylose and XOs with degree of polymerization （DP） from two to four were estimated. Furthermore, the membrane structure parameters were estimated by Steric-hindrance pore model. When feed concentration （total saccharide/syrup）, membrane system temperature and trans-membrane pressure were 8.4%, （30.1±2.1）℃ and （1.58±0.02）×106 Pa, respectively, the flux was （29.4±1.8） L/（m2·h） without declination during diafltration, and the ultimate XOs content reached 92.54% （XOs/total saccharide） from 83.33%. The yield of total saccharide and the loss of xylobinose were 88.39% and 12.45%, respectively, after the addition of three times volumes of water. This investigation provides a basis of parameters for purification by diafiltration, concentration and optimization of those processes. Diafiltration with NF can efficiently remove monosaccharides with less loss of XOs.

关 键 词：低聚木糖 纳滤 膜 不可逆热力学 数学模型 

分 类 号：TQ028.8[化学工程]