Development of copper-charged polypropylene feedspacers for biofouling control

The productivity of membrane filtration is severely lowered by fouling, which is the accumulation of foreign substances on the surface and/or within pores of membranes. Microbial fouling, or biofouling, is the growth of microorganisms on the membrane surface and on the feedspacer as present between the envelopes. The fouling of membranes has demanded and continues to demand considerable attention from industry and research communities. The goal of this project was to develop and investigate the use of copper (Cu)-charged polypropylene (PP) feedspacers that target biofouling control. Cross-flow filtration experiments showed that membranes that used the Cu-charged feedspacers experienced a drastically lower rate of flux decline than the membranes that used unmodified feedspacers. After approximately 48 h of filtration, the flux of membranes that used unmodified feedspacers had declined to approximately 30% of the initial flux (or a 70% flux decline), while the flux of the membranes that used Cu-charged feedspacers had decreased to approximately 75% of the initial flux (or a 25% flux decline). Furthermore, it took membranes that used Cu-charged feedspacers approximately 12 days to reach 35% of the initial flux, a 65% flux decline. This decreased rate of flux decline was contended to be due to less extracellular polymeric substances (EPS) present on the membrane surface. Lastly, no significant amounts of copper leached from the Cu-charged PP during operation.