Comparative Analysis of Metallic Oxides and Nanostructured Materials for Air Purification Applications

Abstract

Air pollution represents one of the major environmental and public health challenges worldwide, generating an increasing demand for efficient air purification technologies. Nanostructured materials have attracted significant attention due to their high surface area, enhanced reactivity, and multifunctional pollutant removal mechanisms. This paper presents a comparative analysis of metallic oxides employed in air purification applications, focusing on titanium dioxide (TiO₂), zinc oxide (ZnO), copper oxide (CuO), nickel oxide (NiO), and magnesium oxide (MgO). The fundamental purification mechanisms, including heterogeneous photocatalysis, reactive oxygen species generation, gas adsorption, and chemisorption processes, are discussed in relation to the structural and electronic properties of each material. The study evaluates the advantages and limitations of these oxides in removing volatile organic compounds, nitrogen oxides, sulphur oxides, and biological contaminants. Furthermore, the performance of metallic oxides is compared with that of carbon-based nanomaterials and metalorganic frameworks, highlighting the benefits of hybrid nanocomposite systems. Attention is given to practical implementation challenges, such as charge carrier recombination, photocorrosion, catalyst deactivation, mass transfer limitations, formation of toxic by-products, and nanoparticle immobilization requirements. The analysis indicates that no single material can provide a universal solution for air purification; instead, future developments should focus on engineered heterojunctions and multifunctional hybrid systems capable of combining adsorption, photocatalytic degradation, and long-term operational stability. These approaches offer promising perspectives for the development of next-generation sustainable air purification technologies.