Mitigation of CO2 emissions by hydrotalcites of Mg3Al-CO3 at 0 °C and high pressure

Review of the Application of Hydrotalcite as CO2 Sinks for Climate Change Mitigation

“…Long et al [77] (Figure 3a) shows how at a temperature of 500 • C for 3 h the layered structure collapses and also shows the production of mixed oxides. Figure 3b shows a similar result, but in this case using a calcination time of 2 h, and the same temperature (500 • C) [33]. This leads to a large saving of energy in the calcination of LDH, with a consequent lowering of the carbon footprint.…”

“…Studies along these lines could fill this information gap. Figure 6A shows the TEM images of LDH and CLDH, after 2 h at 500 °C, obtained by Suescum-Morales et al [33]. In CLDH, small pores were formed, attributable to the dehydration process, dehydroxilation of the OH − groups, and to the decomposition of the interlayer carbonate.…”

“…Garcés Polo et al [91] for CLDH. None of the previous authors [33,67,77,91] indicated the amount of sample used in the calcination, which may have led to these observed differences. Although different calcination temperatures have been used with similar results, there are no economic studies of the cost of calcination; studies of this type, with times, temperatures and quantities of LDH to be calcined, would be very useful for these materials in industrial applications.…”

“…It is very important to choose a suitable calcination temperature, avoiding it being too high (to avoid higher energy consumption), or being too low (not producing the collapse of the structure and hindering a higher CO 2 capture). To distinguish the different stages, it is useful to rely on thermogravimetric analysis (TGA) and differential thermal analysis (DTA) carried out by Suescum-Morales et al [33], shown in Figure 2. It should be noted that different variations in temperature ranges may be encountered, approximately as shown below.…”

“…, where M 2+ and M 3+ represent divalent and trivalent cations, respectively, and A represents the interlayered anion [30][31][32][33][34][35]. Hydrotalcites are known in the bibliography as LDHs (Layered double hydroxides).…”