Porous cellulose nanofiber stringed HKUST-1 polyhedron membrane for air purification

Abstract Among the air pollutants, formaldehyde and particulate matter (PM) 2.5 are the most fatal pollutant sources of indoor pollution. Typically, electric motors have to be used for indoor vent air-clean systems, which are usually high energy consuming and high cost. Herein, we prepared a porous cellulose nanofiber (CNF) stringed HKUST-1 polyhedron membrane on stainless steel screen used as a window screen for air purification. The hierarchical porous structures of CNFs stringed HKUST-1 polyhedrons generate highly nanometer to micrometer pathways for fast air transportation but blocking PM2.5. The highly microporous cavities with open copper sites of HKUST-1 present efficient adsorption for formaldehyde. The corresponding blocking efficiency for PM2.5 is above 95% for a long time, and the adsorption capacity of formaldehyde is 47.71 mg g−1, which can dramatically low down the formaldehyde concentration to be less than 0.1 mg m−3 (the international safe standard of the indoor concentration of formaldehyde). Besides, due to the hierarchical but highly porous and thin thickness (∼5 μm), CNFs stringed HKUST-1 layer also demonstrates air flow rate of 4.6 cm s−1 under 200 Pa, which is enough for the indoor activity. This porous CNFs stringed HKUST-1 polyhedrons membrane on stainless steel screen has great potential for indoor air purification during haze weather.