Abstract
Hydrotalcite-like compound was obtained in compositional range of 0.2<Mg/(Mg+Al)<0.35 by aging the coprecipitated gel from MgCl2 and AICl3 with NaOH in mixed aqueous solution. Its thermal behavior was investigated on the representative composition of Mg/(Mg+Al)=0.25. The decomposed product in a temperature range of 500-800°C was a MgO-Al2O3 solid solution and both MgO and spinel crystallized above this temperature range. Hydrotalcite structure was recovered when the former decomposed product was immersed in sodium carbonate aqueous solution. The hydrotalcite gel could be supported in micro pore with its pore diameter>1μm of porous alumina tube. The hydrotalcite supported porous tube showed a reversible absorption of CO2 from atmosphere. The CO2 absorption behavior was affected with humidity.
