Atmospheric concentrations of several greenhouse gases, in particular, carbon dioxide (CO2) have increased significantly in the recent past largely due to the combustion of fossil fuels. The capture of CO2 from industrial flue gases has therefore become a vital issue attracting the attention of several research groups and organisations in the world. One of the important options to control CO2 emissions is carbon dioxide sequestration that is, capturing and securely storing CO2 emitted from major sources of emission. There are several existing options available for CO2 capture however, each of these systems has its own limitations that impede the technical or economical viability in CO2 post combustion capture systems. Selective adsorption mechanism is a promising technique considered for CO2 separation. A few inorganic materials (zeolites and activated carbons) were found to have good adsorption capacities of CO2. However, they are not attractive for separation from wet feeds at high temperatures due to poor hydrothermal stability. Layered double hydroxides (LDHs) are novel inorganic compounds, and in particular their layered double oxide (LDO) derivatives produced on calcination have desired properties as CO2 adsorbents in post-combustion capture applications. LDHs were prepared by the co-precipitation of divalent Mg and trivalent Al ions in an alkaline solution containing NaOH/Na2CO3. Samples were characterised before and after calcination using various techniques such as FTIR, XRD, TGA and XPS. Different LDH samples prepared were screened to identify the samples with optimum sorption properties. CO2 sorption was measured both volumetrically and thermogravimetrically as a function of calcination and sorption temperatures. Reversible sorption (desorption) capacities were determined using vacuum and temperature cycling methods. A thorough investigation of aspects pertaining to aging, regeneration, impact of water and sorption potentials of the remaining flue gas components including SOx and NOx was conducted during this research. The findings and discussions from this work provide following major contributions to the CO2 capture research. • Significant increase in the CO2 sorption capacity of LDOs by using novel synthesis procedure; • Recyclability with good sorption/desorption potential and more than 90% regenerabilty of LDOs; • Mechanistic aspects of CO2 sorption identified based on heats of adsorption and temperature programmed desorption (TPD) data; • Good hydrothermal stability and SOx sorption capacity with potential for high temperature CO2 separation application from flue gas; • High sorption values and consistent performance even at low CO2 partial pressures of flue gas. The first contribution of this work is related to the synthesis of LDOs leading to best CO2 sorption capacity (1.20 mmol/g). Using novel synthesis procedure an increase of 100% in the sorption capacity was achieved over the sorption capacity of conventionally prepared LDOs. This was possible by choosing optimum reactant concentrations and conditions from the large number of LDH samples prepared and tested. In this study Mg/Al ratio of 3 and CO3 2- concentration of 0.33M were found to be the optimum values leading to high sorption capacity. Further, rate of addition of metal ions and aging of the reaction mixture were also found to produce LDOs with better surface properties including higher surface area. Calcination of LDH at appropriate temperature leading to LDO formation was another important aspect that influenced sorption capacity. Calcination temperature of 400 oC was found ideal for the LDHs prepared with above concentrations. Excellent regenerability and stability of the material after repeated vacuum and temperature cycles with good sorption/desorption potential refers to the second contribution of this work. Sample MAC2 exhibited up to 88% reversibility (desorption) of the total sorption on vacuum evacuation while MAC5 sample which showed maximum sorption (1.20 mmol/g) released up to 58%. However, temperature cycling produced over 70% reversibility with all the samples. High consistency observed in the sorption/desorption patterns after six cycles demonstrated the stability and recyclability of this material. In all the cases more than 90% of the original sorption capacity was recovered after regeneration. Aging or storage of LDOs in the atmosphere found to produce significant structural changes leading to more than 25% reduction in the sorption capacities. An in-situ calcination method was found to be highly productive and suggested for all sorption measurements of LDO to over come these losses. The third contribution of this work relates to identifying the type of sorption and mechanism. Isosteric heat of sorption (71.46 kJ/mol) calculated from the sorption isotherms suggests that it is mostly a chemisorption process. Increase of sorption values with temperature up to 200 oC also proves that the sorption process involves activation energy. TPD results also revealed that only a small amount (7.82%) of total sorption is a weak adsorption. Hence, it is concluded that CO2 sorption on LDO is mostly a chemisorption process rather than physisorption. Finally CO2 sorption on LDO is explained with a suitable mechanism in correlation with TPD results. The fourth contribution is provided by demonstrated hydrothermal stability and superior SOx sorption potential of LDOs. Unlike with other solid sorbents such as zeolites, presence of water in the feed proved to have no adverse impact on CO2 sorption efficiency of LDOs. Water was found to adsorb on LDO simultaneously along with CO2 by increasing the sorption value up to 76% over the maximum dry CO2 sorption value observed at 200 oC. Similar behaviour observed at 300 and 400 oC proved the hydrothermal stability of LDO. The water uptake of the LDOs which was found to be approximately equal to the difference of wet and dry CO2 sorptions proved that water did not restrict CO2 sorption. Consistent sorption/desorption behaviour observed after six temperature cycles also revealed the hydrothermal stability of the sorbent. LDOs found to have very high sorption potential of SOx. Even at low feed concentrations of SOx (0.1% in N2) the sorption values were very high (6.65%) indicating strong affinity of SOx for LDO. SOx sorption was observed to be much stronger as regenerartion levels are less than 50%. All the other constituents of flue gas including NOx showed no sorption property towards LDO. Final contribution resulted from the testing of sorption performance under flue gas concentrations. For the first time LDOs were tested using mixed gas containing 14% CO2 in wet and dry conditions. LDO demonstrated excellent sorption/desorption behaviour with the sorption values equivalent to 70% of the single gas measurements even though CO2 concentration decreased by seven times. The performance in the presence of water was similar to that observed in the case of single gas. Temperature cycling between 200- 300 oC found to be highly effective with 70% reversibility both in dry and wet conditions. Preferential sorption of SOx over CO2 was observed to influence CO2 sorption capacity. Future research should be aimed at further improvement of the CO2 sorption capacities of LDOs by introducing alkali or alkali earth metal oxide promoters. Vacuum temperature swing adsorption (VTSA) method will be considered to achieve high sorption reversibility. Membrane synthesis using LDOs will be another interesting aspect to consider.