大黄素等天然药物的纳滤行为

Retention behavior of composite nanofiltration membrane to the crude medicines

以NF270纳滤复合膜对几种不同分子量的天然药物(如大黄素、咖啡因)进行了纳滤行为研究,并考察了操作压力、浓度、pH、离子浓度等因素对纳滤膜截留行为的影响.结果表明,NF270纳滤复合膜截留分子量在300左右(例如对相对分子质量为270.23的大黄素几乎100%截留,对相对分子质量较小的咖啡因截留率小于60%);随着pH的增大,纳滤膜对大黄素的截留率稍有下降,对其他三种药物的截留率略有升高;改变溶液的离子浓度,纳滤膜的截留率和通量均下降.选择适宜的操作条件可以实现天然药物的提取、分离和浓缩.

The retention behavior to the crude medicines （such as Emodin and Coffeine） by NF-270 which is a thin film composite nanofiltration membrane was studied. The main factors affecting nanofiltration process such as operation pressure, pH, concentration and ion concentration were also investigated. The results show that the nanofiltration membrane has a MWCO about 300（such as the salt rejection to Emodin with a molecular weight 270.23 is near 100% and less than 60% to Coffeine with a molecular weight less than 200）;As the pH accretion, the rejection of membrane to Emodin falls but to other three crude medicines increase. Changing ion concentration resulted in both rejection and permeate flux decline. The retention experiment also show that the distilling, separation and condense of crude medicine can achieve by using nanofiltration technology with feasible operation conditions.