超滤结合电渗析技术纯化铁皮石斛多糖的研究

Purification of Dendrobium officinale polysaccharides using ultrafiltration combined with electrodialysis technology

该研究采用两步超滤与电渗析相结合的技术制备高纯度、低重金属离子含量的铁皮石斛多糖。在第一步超滤过程中添加0.5 mol/L的NaCl提高多糖的提取率,随后通过电渗析去除NaCl和重金属离子。在第二步超滤中去除单糖、寡糖等小分子杂质,得到高纯度的铁皮石斛多糖。实验优化了超滤和电渗析的工艺操作参数,研究表明,当进料温度为35℃,料液pH值为6时,多糖的回收率和纯度最佳,分别为78.2%和86.4%。当电渗析电压为15 V,电渗析时间为30 min时,铅离子脱除率达到95.8%,铜和汞离子脱除率分别为26.8%和73.3%。

In this study,a novel process coupling two-step ultrafiltration(UF)and electrodialysis(ED)was developed to produce high-purity Dendrobium officinale polysaccharides.In the UF-1st process,0.5 mol/L NaCl was introduced to increase the extraction rate of polysaccharides.Afterwards,the ED process was employed to remove NaCl and heavy metal ions from the extraction.The high-purity Dendrobium officinale polysaccharides were obtained after removing small-molecule impurities such as monosaccharides and oligosaccharides through the UF-2nd process.The operation parameters of the UF and ED processes were optimized in the present study.When the temperature and pH of the feed fluid were at 35℃and 6,the optimal recovery(78.2%)and purity(86.4%)of polysaccharides were achieved.When the voltage and ED time were set at 15 V and 30 min,the removal rate of lead,copper,and mercury reached 95.8%,26.8%,and 73.3%,respectively.