Controllable Preparation of Mesoporous MnO2 Loaded on Activated Carbon Nanofiber Membrane for Persistent Formaldehyde Removal from Indoor Air

Comprehensive treatment of indoor air pollution (including formaldehyde and PM2.5) using functional fiber filter materials has received increasing attention. This paper describes the preparation of a functional fiber with an adsorption-catalytic degradation performance for formaldehyde; mesoporous MnO2 is constructed on the surface of polyacrylonitrile (PAN)-based activated carbon nanofibers (ACNF) using a redox hydrothermal method. A wet non-woven fabric/melt-blown non-woven/MnO2@ACNF (WNF/MnO2@ACNF/MB) composite air filter is then prepared based on this fiber membrane. Under optimal conditions (reaction temperature: 120 °C, pH: 7.0, potassium permanganate concentration: 0.03 mol L−1, and reaction time: 6 h), porous coatings (pore sizes ranging from 3−40 nm) formed on the surface of ACNF, which were constructed from δ-MnO2 nanosheets. The test results of continuous high concentration formaldehyde supply showed that ACNF membrane failed within 6 h under high humidity, while MnO2@ACNF The formaldehyde removal efficiency of the membrane was still close to 80%. In situ infrared test results indicate clearly that formaldehyde decomposed into CO2 and H2O on the surface of the fibers. The WNF/MnO2@ACNF/MB composite filter displays excellent filtration performance for particulate matter (PM), proving to be an exceptional method for producing functional filtration media for PM2.5 and formaldehyde removal from indoor air.