Desalination, Vol.140, No.1, 55-65, 2001
Effect of membrane support material on permeability in the microfiltration of brining wastewater
The cross-flow microfiltration (MF) of brining wastewater was conducted after chemical pretreatment with the goal of reusing the treated wastewater. The effect of membrane support material on permeability was investigated in terms of flux decline and recovery with permeate or acid back-washing. During the MF of pretreated brining wastewater, there was little flux improvement for the Zr/C membrane as a result of back-washing, although the back-washing for the other types of polymeric and ceramic membranes used always enhanced the recovery of the permeate flux. The significance of membrane fouling for the Zr/C membrane was demonstrated via an evaluation of the hydraulic resistances after MF with back-washing, suggesting that membrane fouling was greatly dependent on the support material as well as the skin material. The carbon support of the Zr/C membrane played an important role in nullifying the effectiveness of backwashing because the carbon support was able to sorb organic matter during MF with back-washing, resulting in an increase in irreversible membrane fouling. From these findings, it is clear that the membrane support material must be taken into account in elucidating the behavior of membrane fouling and the flux recovery by back-washing during MF.