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Abstract
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CaO-based adsorbents have been widely determined as one of the best materials for high-temperature CO2 capture via the calcium looping process, suffering from the sintering phenomenon during some carbonation/calcination cycles that could reduce CO2 uptake capacity. The costly Zr-based promoters have shown the best effect in raising the multicyclic durability of CaO adsorbents. In this research, for the first time, 10 wt% of waste date kernel (DK) as a pore former was utilized to boost the structural and adsorptive properties of Ca-Zr-O adsorbent synthesized considering a Ca/Zr weight ratio of 10/1. The textural, structural, and adsorptive properties of these fabricated adsorbents were investigated by XRD, FESEM, EDX, N2 adsorption/desorption, and TGA analyses. Such a cost-effective CaO promoted with DK and Zr-based promoter (CaO-C-Zr) presented superior textural features compared to the DK free Ca-Zr-O sample (CaO-Zr). In addition to significant enhancement in morphological porosity, simultaneous incorporation of DK powder and Zr-based promoter increased values of exterior surface area and pore volume of CaO nanoparticles from 11.69 m2/g and 0.054 cm3/g to 20.54 m2/g and 0.155 cm3/g, respectively. With CaO being merged with a minor DK pore-former and Zr-based promoter, the CaZrO3 distribution was homogenized, leading to a ~ 14% increment in sorption durability. Analyzed under harsh process conditions, the average sorption capacity and uptake stability of CaO over fifteen cycles reached 18.85 wt% and 57.43% from 9.26 wt% and 37.76%, respectively, indicating 103.5 and 151.5% increase in average and ultimate uptake capacity.
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