ORIGINAL ARTICLE
Mechanism of Formaldehyde Reduction with Fired Scallop-shell Powder: Comparison between CaO and Ca(OH)2
2011 Volume 3 Issue 2 Pages 282-287
Details
2011 Volume 3 Issue 2 Pages 282-287
The formaldehyde reduction activity of fired scallop-shell powder was investigated by means of ab initio and density functional theory calculations. The two active components of fired scallop-shell powder are considered to be calcium oxide (CaO) and calcium hydroxide (Ca(OH)2). In this study, finite-sized cluster models of these compounds were made and the interaction between each of them and formaldehyde (HCHO) was analyzed theoretically. Comparing the adsorption states of HCHO contained in the two models, one H atom of HCHO in the Ca(OH)2-HCHO model was found to transfer to the adjacent O atom to form a Ca-OH-C-H-OH five-membered ring structure. This change would lead HCHO to decompose. By contrast, in the case of the CaO-HCHO model, HCHO attaches only through a Ca-O=CH2-O bridged geometry and does not decompose. This result would indicate why Ca(OH)2 is effective for HCHO reduction.
