Efficient Oxidative Removal of Indoor Formaldehyde Using Functionalized Activated Alumina

Formaldehyde (HCHO) has become a significant indoor air pollutant, arising from the widespread use of decorative and construction materials. Adsorption is the most convenient method for HCHO removal. However, the current adsorption is limited by the current low adsorption capacity and desorption. Herein, activated alumina (γ-Al₂O₃) loaded with permanganate was proposed for the efficient oxidative removal of indoor HCHO. The results demonstrate that the permanganate-containing alumina-based pellets (PAP) with 75% of alumina (PAP-75) displayed the highest adsorption capacity of 10,800 μg g^-1. This high adsorption capacity is mainly attributed to the presence of numerous pore structures within the pellets, good dispersion of permanganate on the surface and inside the spheres, abundant surface-active sites, and high porosity. The adsorption kinetics explains that the chemisorption, intraparticle diffusion, and film diffusion are the primary rate-controlling steps. This study provides an effective strategy for further improving alumina-based adsorption materials for HCHO removal.