Removal of formaldehyde by hydroxyapatite layer biomimetically deposited on polyamide film.

Some harmful volatile organic compounds (VOCs), such as formaldehyde, are regulated atmospheric pollutants. Therefore, development of a material to remove these VOCs is required. We focused on hydroxyapatite, which had been biomimetically coated on a polyamide film, as an adsorbent and found that formaldehyde was successfully removed by this adsorbent. The amount of formaldehyde adsorbed increased with the area of the polyamide film occupied by hydroxyapatite. The amount of adsorbed formaldehyde and its rate of adsorption were larger for hydroxyapatite deposited on polyamide film than for the commercially available calcined hydroxyapatite powder. This high adsorption ability is achieved by the use of nanosized particles of hydroxyapatite with low crystallinity and containing a large number of active surface sites. Therefore, hydroxyapatite biomimetically coated on organic substrates can become a candidate material for removing harmful VOCs such as formaldehyde.