Electrospun-SiO₂-Nanofiber-Reinforced Cellulose Aerogel Loaded with ZIF-67 for Air Filtration and Formaldehyde Adsorption

Indoor air pollution, which is detrimental to the human respiratory, nervous, and cardiovascular systems, is of increasing concern because considerable time is spent indoors. Thus, there is an urgent need to develop improved methods for controlling indoor air pollution. In this study, electrospinning and freeze-drying methods are used to prepare a cellulose-silica nanofiber (C-SNF) aerogel loaded with zeolitic imidazolate framework-67 (ZIF-67) for use in indoor air purification systems. The C-SNF aerogel doped with 0.75 wt.% SiO2 nanofiber (SNF) exhibits a maximum compressive stress of 8.7 MPa, which is higher than that (6.4 MPa) of a pure cellulose aerogel. The compressive modulus of the aerogel exceeds 85% of its original value after 100 compression cycles. The C-SNF aerogel exhibits a filtration efficiency of 99.91% against 0.3 mu m salt particles at 32 L min(-1), which is higher than that of the pure cellulose aerogel (51.25%). Moreover, a stable removal efficiency of 99.92% toward 2.5 mu m particulate matter (PM2.5) is observed after ten cycles. Notably, the addition of ZIF-67 to C-SNF (ZIF-67@C-SNF) aerogel by in situ growth method resulted in a porosity of 92.3% and formaldehyde removal of 93.75%. The ZIF-67@C-SNF aerogel can be used in various applications including indoor-air and adsorptive-filtration masks.