Chitosan-based nanofibrous membranes for antibacterial filter applications

Nanofibrous membranes have drawn considerable interest for filtration applications due to their ability to withstand high fluid flux while removing micro- and nano-sized particulates from solution. The desire to introduce an antibacterial function into water filter applications presents a challenge to widespread application of fibrous membranes because the addition of chemicals or biocides may produce harmful byproducts downstream. Here, we report the development of chitosan–polycaprolactone (PCL) nanofibrous membranes to utilize the natural antibacterial property of chitosan for antibacterial water filtration. Chitosan–PCL fibers with diameters of 200–400 nm and chitosan contents of 25, 50 and 75 wt% were prepared by electrospinning. In a series of bacterial challenge tests, chitosan–PCL fibrous membranes significantly reduced Staphylococcus aureus adhesion compared to PCL fibrous membranes. In water permeability and particulate size removal tests, fibrous membranes with 25% chitosan supported the greatest water flux (∼7000 L/h/m2) with 100% removal of 300-nm particulates, while maintaining the membrane integrity. This study demonstrates the potential of chitosan–PCL nanofibrous membranes as pre-filters for water filtration systems that demonstrate combinatorial filtration and intrinsic antibacterial advantages.