Abstract
The volatile organic compound (VOC) reduction activity of scallop shell powders fired at 300, 600 and 900°C was examined using formaldehyde (HCHO). Raw shells as well as fired shells immediately after firing at several temperatures, except for 600°C, were found to gradually remove HCHO from the air. In the case of shell powders stored for 3 months after firing, the HCHO reduction activity of the powder fired at 900°C was obviously improved, with the HCHO concentrations rapidly reaching zero within 20 min. It has been found by X-ray diffraction measurements that shell powder stored for 3 months after firing at 900°C contains a small amount of calcium hydroxide (Ca(OH)2) generated from calcium oxide (CaO). Our results suggest that Ca(OH)2 may be the effective ingredient in the HCHO reduction.