Ecofriendly Electrospun Membranes Loaded with Visible-Light-Responding Nanoparticles for Multifunctional Usages: Highly Efficient Air Filtration, Dye Scavenging, and Bactericidal Activity.

Ambient particulate matter pollution has posed serious threats to global environment and public health. However, highly efficient filtration of submicron particles, the so-named "secondary pollution" caused by, e.g., bacterial growth in filters and the use of nondegradable filter materials, remains a serious challenge. In this study, poly(vinyl alcohol) (PVA) and konjac glucomannan (KGM)-based nanofiber membranes, loaded with ZnO nanoparticles, were prepared through green electrospinning and ecofriendly thermal cross-linking. Thus obtained fibrous membranes not only show highly efficient air-filtration performance but also show superior photocatalytic activity and antibacterial activity. The filtration efficiency of the ZnO@PVA/KGM membranes for ultrafine particles (300 nm) was higher than 99.99%, being superior to that of commercial HEPA filters. By virtue of the high photocatalytic activity, methyl orange was efficiently decolorized with a removal efficiency of more than 98% at an initial concentration of 20 mg L^-1 under 120 min of solar irradiation. A multifunctional membrane with high removal efficiency, low flow resistance, superior photocatalytic activity, and superior antibacterial activity was successfully achieved. It is conceivable that the combination of a biodegradable polymer and an active metal particle would form an unprecedented photocatalytic system, which will be quite promising for environmental remediation such as air filtration and water treatment.