Separation performance of horizontal and vertical polyethersulfone hollow fiber UF modules

Abstract

The effect of hollow fiber module positions (horizontal and vertical) on separation performance for PVA solution by using polyethersulfone (PES) hollow fiber ultrafiltration (UF) membrane with the molecular weight cut-off (MWCO) 30 000 has been discussed. Experimental results illustrated that the suitable operation conditions for PVA solution were as follows: trans-membrane pressure 2.1 bar, solution temperature 75 °C and feed velocity 0.32 m/s. Under these suitable operation conditions, the permeate flux is from 36.8 L/(m2·h· bar) to 42.9 L/(m2· h· bar) for the horizontal module and from 39.8 L/(m2· h· bar) to 66.6 L/(m2· h· bar) for the vertical module. Besides, the separation performance of PES hollow fiber UF membrane was better by using vertical hollow fiber module than by using horizontal hollow fiber module. When the trans-membrane pressure increased from 1 bar to 2.1 bar, solution temperature from 50 °C to 75 °C, feed solution velocity from 0.16 m/s to 0.32 m/s, the PVA rejection would increase from 95.8% to 99.7%, 95.4% to 98.6%, 95.8% to 99.2% for horizontal module respectively, and from 98.8% to 99.8%, 98.6% to 99.4%, 98.5% to 99.4% for vertical module respectively. Therefore, PVA rejection in PES hollow fiber UF process was more than 98.5% for vertical module, and it is suitable for PVA recovery from wastewater.