Performance assessment of functionalized electrospun nanofibres for removal of pathogens

Abstract

Perfonnance Assessment of Functionalized Electrospun Nanofibres for Removal of PathogensKeywords: functionalised nanofibre, pathogen removal, membrane filtration. The c1ectrospinning technique is a process for making continuous nanofibrcs in a nonwoven fonn. This process spins fibres ranging from 80 om diameter to several hundred nanometers. The non-woven structure is produced by app lying a high voltage to the anode, submerged in a spinn ing solution. This produces a charged jet of fluid when the electrical force is highcr than the surface tension of the solution and the fibres are collected on a grounded aluminum plate. Nanofibres have a small pore size and a large surface area to volume ratio compared to nonwovens (this ratio for a nanofibre can be as large as 1000 times of that of a microfibre). This, together with their low density and interconnected open pore structure. make the nanofibre nonwoven appropriate for a wide variety of filtration applications (Huang et al.. 2003). Due to the large effective surface areas. nanofibres can carry functional agents with different properties. such as biocidcs. With microfiltration membranes it is possible to retain suspended solids and micro-organisms. The added value of the tested nanofibre microfiltration membranes functionalized with silver nanoparticles (nAg) or other biocides to pathogen removal was studied. The biocides used in this study are commercially available. WSCP for example. is used as a cooling tower biocide and is applied directly into the water. Silver nanoparticles are nowadays implemented in a wide variety of consumer products for antimicrobial controL The aim of the study is to examine the effectiveness of different biocides and the possibility to electrospin them in a steady state nanofibre membrane. The results show that due to the silver nanoparticles and the funct ionalisation with biocides in the functionalized membrane a higher efficiency (3.9 10giO - 5,5 10glO) could be achieved. Further, the removal of pathogens is a factor 100 (2 10g10) higher with a WSCP (5%) than conventional microfihration. Functionalisation with Ag nanoparticles gave a 4 10gi0 removal. It is generally known that these particles only have effect on gram negative bacteria such as E. coli. WSCP and bronopol are bactericides that can be applicd on c1ectrospun nanofibres and it has also effect on gram positive bacteria (Chen et aI., 2008). The removal with a non-functionalised membrane is not as good as other micro-filtration studies. With other commercial membranes a 2 log I 0 - 4 logl 0 removal is possible (Zodrow et al.. 2009).