Understanding PVDF ultrafiltration membrane fouling behaviour through model solutions and secondary wastewater effluent

Abstract

In this work, we investigated the fouling behaviour of polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes. PVDF UF membranes prepared by the phase separation method were used to filter four sample solutions, namely bovine serum albumin (BSA), sodium alginate (SA), humic acid (HA) and secondary wastewater effluent organic matter (EfOM). Fouling experiments were carried out in a dead-end filtration set-up. Besides, the removal rate of dissolved organic carbon, the distribution of molecular weight and the permeability of feed water were inspected through direct comparison of the surface morphology of an uncontaminated and a contaminated membrane. The different fouling behaviours of BSA, SA, HA and EfOM were noted. It was found that the flux of the BSA-fouled membrane declined sharply at the initial filtration stage, but a more significant flux decline occurred for the SA-fouled membrane at the later filtration stage. For the HA-fouled membrane, a gradual flux decline was observed throughout the whole filtration stage. In three samples, HA generated the smallest flux decline rate and BSA produced the largest rate. Moreover, the fact that it took a very short time to approach about 50% flux reduction indicated that membrane fouling mainly occurred in the initial filtration stage. It was also found that the gel-layer structure on the membrane surface was strongly associated with the fouling behaviour of the membrane.

Keywords:

• Polyvinylidene fluoride
• Fouling behaviour
• Foulant types

Acknowledgments

Financial support for this study was provided by the National Natural Science Foundation of China (Grant Nos. 51178378, 51278408 and 51008243), the Shanxi Province Science and Technology Innovation Projects (Grant No. 2012KTCL03-06) and the Foundation of Shanxi Educational Committee (Grant No. 2013JK0884).

Notes

Presented at the Conference on Water Resources and Urbanization Development, 26–27 September 2012, Tianjin, China