A Multifunctional Nanofiber Membrane Integrating PM Filtration with Rapid, Visual, and Selective Formaldehyde Sensing

In this study, a polyacrylonitrile (PAN) nanofibrous membrane demonstrating both high particulate matter filtration efficiency and formaldehyde visual detection capabilities was obtained by electrospinning. The additive polyvinylpyrrolidone (PVP) was introduced to adjust the structural characteristics and hydrophilicity of the membrane, while methyl yellow (MY) was added as a colorimetric indicator. Sulfamic acid was then loaded on the membrane to obtain the sensing property. The obtained nanofibrous membrane exhibits excellent PM_0.3 filtration efficiency (99.88%) with low filtration pressure drop (159.3 Pa). The sensing accuracy for formaldehyde can reach below 50 ppb (World Health Organization, safety concentration <80 ppb), and it can identify formaldehyde at a concentration of 1 ppm within 10 min. Owing to the specific reaction between sulfamic acid and formaldehyde, the membrane exhibited excellent anti-interference performance against other volatile organic compounds. This nanofiber colorimetric sensing membrane holds great potential for application in respiratory protective equipment.