Nanofibrous microfiltration membranes capable of removing bacteria, viruses and heavy metal ions

•Nanofibers were modified to enhance surface area and functions for adsorption.•High surface area, porosity and functional group density improve separation membrane.•New MF filters can remove bacteria, viruses and ions from water at low pressure.

A novel class of microfiltration membrane, based on a two-layered nanoscale polyacrylonitrile (PAN)/microscale polyethylene terephthalate (PET) fibrous scaffold containing infused ultra-fine functional cellulose nanofibers (diameter about 5 nm), was demonstrated. These membranes can simultaneously remove bacteria, viruses and/or toxic heavy metal ions. To be specific, the demonstrated membrane was capable of completely removing Escherichia coli (by size extrusion), reaching a LRV of 4 for MS2 virus removal and having the adsorption capability of 100 mg Cr (VI) or 260 mg Pb (II) per gram of cellulose nanofiber, while maintaining a high permeation rate (1300 L/m2h/psi). The development of these membranes was based on the creation of a web-like structure with very high charge density and large surface area per unit volume for adsorption of contaminant molecules.

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