Critical review of catalytic oxidization and chemisorption methods for indoor formaldehyde removal

Formaldehyde, an irritant and cacinogent to humans, is one of the most concerning indoor gaseous pollutants because it is often found in buildings and poses a potential health risk to occupants even at a very low concentration level. Chemisorption and catalytic oxidization are two promising methods for indoor formaldehyde removal. This review covers the following aspects of the two formaldehyde removal methods: reaction mechanism, activity test method, materials, performance, and effect of environmental conditions (temperature, relative humidity, concentration level, and velocity) on the removal performance. Results show that a supported noble metal (e.g., Pt) and metal oxide (e.g., MnO₂) are the most effective catalysts, but usually require a high temperature for complete decomposition of formaldehyde. An amino group containing activated carbon is the most commonly used chemisorbent. The effect of the noble metal loading and the preparation method of the noble metal catalyst are also discussed. Possible applications in a building HVAC system are discussed along with needed future research.