Infra-red study of surface carbonation on polycrystalline magnesium hydroxide

Abstract

Carbonation of Mg(OH)2 at 300 °C was studied by Infrared spectroscopy. Dehydroxylation and carbonation reactions were carried out in consecutive manner via 2-step procedure. Unidentate carbonates were produced only on defective surface of MgO in situ generated by dehydroxylation of Mg(OH)2 under dynamic vacuum. Bicarbonates and bidentate carbonates were not observed. Generation of unidentate carbonates was accompanied by decrease of 1-coordinated hydroxides and concomitant increase of muti-coordinated hydroxides on the surface. Postulated reaction mechanism for the carbonation of Mg(OH)2 at 300 °C was proposed.