有机溶剂纳滤膜的润湿性对渗透和分离性能的影响

有机溶剂纳滤是一种绿色、高效、节能的新型膜分离技术，在回收和处理有机溶剂中具有广泛的应用前景。本文采用浸渍法分别将聚合物聚二甲基硅氧烷（PDMS）、嵌段聚醚酰胺（PEBAX2533）和聚乙烯醇（PVA）与聚砜（PS）超滤基膜复合，制备了3种不同润湿性的聚合物耐溶剂纳滤膜，研究了PDMS/PS、PEBAX/PS和PVA/PS复合膜对甲醇、乙醇、异丙醇、正己烷、正庚烷的渗透性能，考察了3种聚合物膜对伊文思蓝/甲醇溶液的有机溶剂纳滤性能。结果表明，有机溶剂在不同润湿性复合膜的渗透和传递性能与溶剂本身的溶度参数、分子量、黏度和极性等有很密切的相关性，溶剂的分子量、黏度、分子动力学直径越小，在同一极性复合膜中渗透通量越大；对伊文思蓝/甲醇溶液的有机溶剂纳滤分离表明，PDMS/PS和PEBAX/PS复合膜的截留率均可达90%以上，通量分别为 58.0L/(m²·h·MPa)和72.2L/(m²·h·MPa)；PVA/PS复合膜的截留率为85.1%左右，通量为57.5L/(m²·h·MPa)。

Effect of wettability of organic solvent nanofiltration membrane on its permeability and separation performance

Organic solvent nanofiltration (OSN) is a new membrane separation technology with advantage of high efficiency, environmental benign and energy-saving, showing potential applications in recovery and treatment of organic solvents. Herein, three OSN membranes with different wettability were fabricated by immersing polysulfone (PS) ultrafiltration membranes in PDMS, PEBAX and PVA solution, respectively. The permeability of the prepared PDMS/PS, PEBAX/PS and PVA/PS composite membranes to methanol (MeOH), ethanol (ET), isopropanol (IPA), n-hexanes and n-heptane and the nanofiltration performance of the three membrans to evans blue (EB) methanol solution were explored. The results showed that the flux of organic solvents was highly related to the membrane surface wettability and molecular weight, viscosity, solubility parameters and polarity of organic solvents. The hydrophobic PDMS/PS and PEBAX/PS composite membranes exhibited the high flux of 58.0 and 72.2L/(m²·h·MPa) to organic solvents, respectively, and the rejection of EB of the hydrophobic membrane reached more than 90%, while the hydrophilic PVA/PS displayed 85% retention of EB along with a flux of 57.5L/(m²·h·MPa).