PEG和PEO混标法测定中空纤维超滤膜切割分子量方法的研究

Studies on measuring method of molecular weight cut off for ultrafiltration membrane with mixture of polyethylene glycol and polyethylene oxide

采用聚乙二醇（PEG）和聚环氧乙烷（PEO）制成相对分子质量范围为2 000~230 000的混合截留物质溶液（混标）,在参考截留操作条件下,使用高效凝胶排阻色谱对中空纤维超滤膜切割分子量（MWCO）的检测方法进行了研究.该方法对同一样品测量结果的相对误差为5.1%~5.6%.参考截留操作条件为：温度（25±1）℃;跨膜压差（100±5）kPa;测试系统的雷诺数控制为1 600~1 800,膜面错流速度为1.4~2.3m/s;回收率不大于5%;模型组件中膜丝根数为20~30根、长度为170~180 mm;截留实验操作后要采用150kPa跨膜压差进行15min以上的反冲洗,使之纯水透过率恢复到初始纯水透过率的70%以上.

The mixture retention solution with polyethylene glycol （PEG） and polyethylene oxide（PEO）, the relative molecular mass range from 2 000 to 230 000, is prepared to measure the molecular weight cut off （MWCO） for uhrafihration membrane by high performance size exclusion chromatography（HPSEC） in reference operating conditions. The relative deviation of the results of the MWCO among the three parallel testing by single sample is 5. 1% -5. 6% . The reference operating conditions are： the temperature is （25±1） ℃,the trans-membrane pressure （TMP） is （100±5） kPa, the Reynolds numbers （Re） of the testing system is controlled to be 1 600-1 800, the cross-flow velocity is controlled to 1.4-2.3 m/s in operation, the recovery rate is controlled to be smaller than 5 %, 20-30 fibers with 170-180 mm length in one standard membrane module package;the membrane in the standard membrane module need to be back washed after each testing with TMP 150 kPa by 15 rain or more, so as to make the pure water fluxes of the membrane recovered to more larger than 70 % of its initial pure water fluxes.