The effects of pretreatment condition of non-woven fabrics on the PVC-co-PVAc-OH membrane performances

Abstract

In this paper, flat-sheet membranes were prepared with PVC-co-PVAc-OH material/poly (ethylene glycol) 2000/dimethylformamide using different types of non-woven fabrics (NWFs) as substrate using phase inversion method. NWFs were immersed into organic solvent, and then exposed to a humid environment for certain time before casting a thin liquid film onto them. The effects of the substrate, NWFs, and the pretreatment method of the NWFs on the structure and performance of membranes were mainly studied. The types of NWFs and its pretreatment conditions have significant impacts on the performances of the membrane: firstly, types of solvent to immerse NWFs have little impact on final membrane performance; secondly, both pure water flux and the corresponding rejection increased, and then decreased dramatically, with longer immersion time; however, when the immersion time was more than 12 h, the surface of NWF was wrinkled slightly; finally, in order to prepare a membrane with high rejection, two approaches are possible: either prolonging the solvent evaporation time and increasing of the temperature or decreasing the relative humidity in the environment. In the experiment, the membranes were used to purify the Bovine serum albumin solution by the dead-end membrane module. And all the results were conformed to scanning electron microscopy observation, pore size distribution or water content of the membranes.

Keywords:

• Non-woven fabrics
• Pretreatment conditions
• Performances

Acknowledgements

Support for this work was provided by the Beijing Natural Science Foundation (Project No. 2122009). The authors express appreciation to Professor Angel Perez Sainz, currently at Beijing University of Technology, for very extensive editing.