Na2CO3/gamma-Al2O3 is one of the most promising sorbents to capture CO2 from industrial flue gas streams due to its high efficiency in low-temperature and low cost. The textural properties of the gamma-Al2O3 support, such as specific surface area and pore volume play key roles in performance of the sorbent. Therefore, the aim of this study was to improve the sorbent performance, using several gamma-Al2O3 supports, prepared through a modified sol-gel process in the presence of polyethylene glycol (PEG). N-2 adsorption-desorption analysis showed that the pore volume and specific surface area of the sample with the PEG/Al(OPri)(3) mole ratio of 0.05 were, respectively, about 340 % and 38 % higher than the sample synthesized in the absence of PEG. In addition, improving the specific surface area and pore volume of gamma-Al2O3 enhanced the total CO2 capture capacity of a Na2CO3/gamma-Al2O3 sorbent by 34 %. Moreover, the effect of Na2CO3 loading on the best gamma-Al2O3 sample was investigated, and the optimum loading of Na2CO3 and the corresponding total CO2 capture capacity were observed to be 50 wt.% and 131.6 mg CO2/gsorbent, respectively. Finally, the regeneration conditions of the sodium-based sorbent were determined using chemical kinetic study and temperature programmed desorption (TPD) analysis. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.