CO2 capture activity of a novel CaO adsorbent stabilized with (ZrO2+Al2O3+CeO2)-based additive under mild and realistic calcium looping conditions

Abstract The present investigation concentrated on the configuration of a novel synthetic adsorbent via the sol-gel auto-combustion method through incorporating ZrO2, Al2O3, and CeO2 simultaneously during the development of CaO adsorbent. The impacts of disparate calcium precursors and molar ratios of calcium precursors to promoters were also studied. The adsorbent developed from soluble calcium nitrate precursor showed the higher surface area and smaller CaO grain size accompanied by a more enhanced capture capacity and CaO conversion at the mild and realistic process conditions during the carbonation-calcination cycles. Among synthesized adsorbents with disparate the molar ratio of Ca/(Ze + Al + Ce) (calcium precursor: promoters), the prepared sample with the molar ratio of 20/1 (CN/20) indicated the most promising performance with the best morphological properties, higher sorption capacity, and CaO conversion in comparison with 15/1 (CN/15) and 30/1 (CN/30) during 18 carbonation-calcination multiple cycles under the realistic condition. The most highlighted result of this work was that cyclic performance of modified adsorbents is linearly proportional to their morphological properties, in that CN/20 with the largest free surface area of 31.3 m2/g captured 4.23 g CO2/gr adsorbent, 9.58 % and 11.6 % higher than that captured by CN/15 and CN/30, respectively, during 18 realistic carbonation/calcination cycles.