In a typical run, 40 g of the dry sample impregnated with ZnCl2 was placed into the reactor and CO2 40 g of the dry sample impregnated with ZnCl2was placed into the reactor and CO2 was passed through at aflow rate of 0.1 dm3 /min; the system was heated at a rate of 20 °C min−1in a muffle furnace.