新型PVA/PA复合膜的运行工艺对渗透汽化性能的影响

研究了聚乙烯醇（PVA）/聚酰胺（PA）复合膜渗透汽化（PV）分离异丙醇（IPA）/水混合物时运行工艺的影响,模拟了渗透通量（J）预测方程。结果表明,PVA/PA复合膜在料液中w（IPA）%在0～95%范围内或在25℃～100℃的操作温度范围获得的渗透液中IPA含量w′（IPA）]都小于1%,J随料液中w（IPA）%的下降或操作温度的提高而增加。分离性能预测方程的拟合结果与试验数据有良好一致性。在室温条件下,经过90 d的间歇运行或经过120 d的长期贮存后,PVA/PA复合膜的分离性能稳定,在IPA/水混合物的共沸温度80.4℃运行时的J为73.1 g/m^2·h,渗透液中的水含量w′（H2O）]都大于99.5%,展示了其在食品、生物、制药和化学等工业中将具有良好的应用前景。

Effects of Operation Processes on the Pervaporation Performance of New PVA/PA Composite Membrane

The effects of concentration of the isopropanol （IPA） in the feed and the operation condition on pervaporation（PV） separation performance of the polyvinyl alcohol and polyamide （PVA/PA） composite membrane were emphatically investigated. The forecast equations of the total permeating flux （J） of water and isopropanol were also established by the regression of experimental data. It was shown that the IPA concentration in the permeates w＇ （ H2 O） ] gained in the full concentration of the feed or at the operation temperature of 25 ℃-100 ℃ was always less than 1.0% （weight ratio）. The permeating flux increased with the decrease of the feed concentration or the increase of the operation temperature. The data from forecast equations were consistent with the test results in PV separation. The separation performances of the composite membrane operated for 90 d or stored for 120 d at ambient temperature showed stable separating characteristic. The permeating flux was 73.10 g/m^2· h, the water concentration in the permeate w＇（H2O）] was more than 99.5 % weight ratio when the PVA/PA composite membrane was used to separate azeotropic mixture of IPA/ water at 80.4 ℃. The PVA/PA composite membrane will possess good application perspective in the food,biological pharmaceutical and chemical engineering industreis.