Anti-biofouling enhancement of a polycarbonate membrane with functionalized poly (vinyl alcohol) electrospun nanofibers: Permeation flux, biofilm formation, contact, and regeneration tests

 Water is essential to humanity, and is used for a variety of purposes - drinking, washing, extinguishing fires, etc. An ample supply of clean water is important, as it is used in prevention of flooding, droughts and pollution of rivers, supplementation of underground water and for industrial purposes. In the course of such uses, recycling is essential, as is a wastewater treatment process to remove pollutants, which involves the use of absorbents or membranes. Membranes are thin materials that act like filters, and are used in purification regardless of the number of microbes existing in the water. However, these membranes become contaminated as they filter, and biologically-active organisms accumulate and grow on their surfaces in large quantities to create biofilm (i.e. ‘membrane biofouling’). Membrane biofouling degrades membrane lifespan and also purifying performance, which results in decreased effectiveness and increased maintenance costs. Researchers are active in seeking ways to reduce membrane fouling, through the use of new materials for membranes or developing additives.

 Professor Song-Bae Kim of Rural Systems Engineering Program, Seoul National University and his team of researchers presented a benzyl triethylammonium chloride (BTEAC)-functionalized poly (PVA) in their study on this matter. PVA nano-fiber with a BTEAC coating is applied on the surface of a polycarbonate (PC) membrane using an electrospinning device, with the BTEAC preventing the accumulation of microbes as it kills them on contact. Membrane fouling is therefore prevented, and membrane performance enhanced.

 To verify the anti-biofouling performance of an f-PVA/PC membrane, Professor Kim and his team conducted four tests. A flux test showed that the f-PVA nano-fiber enhanced the flux effect of the membrane. A biofilm formation test proved that the f-PVA nano-fiber reduced formation of biofilm on itself, while during a contact test, the f-PVA/PC membrane revealed a more vigorous anti-biofouling activity than that of a simple PC or PVA/PC membrane. This anti-biofouling activity was maintained over six cycles in a regeneration test.

 When all test results were put together, Professor Kim and his team reached the conclusion that BTEAC-PVA nano-fiber can function as an anti-biofouling coating for PC membrane due to its anti-adhesive and anti-bacterial surface modification effects.

 The Environmental Functional Materials and Water Treatment Laboratory, led by Professor Song-Bae Kim, is developing technologies and processes that remove or dissolve hazardous pathogenic microbes and pollutants in the water to an environmentally safe level, through the combined use of environmental engineering, bio-engineering and nano-particle technology. Water can be treated in a variety of ways besides with a membrane, such as with absorbents or ion exchange fibers. Professor Kim’s research team is studying how a high-performing absorbent can be synthesized, which pollutants can be removed by absorbent, and how the performance of adsorbent can change according to the solution pH.

 This study suggests that it is possible to improve water quality in an efficient manner. Better water quality and advanced environmental engineering significantly improves living conditions – and will create a future of abundant safe and clean water.

 

Student Reporter Lim, Dabin / Kim, Jeonghyo