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The novel Carbon Nanotube-assisted development of highly porous CaZrO3-CaO xerogel with boosted sorption activity towards high-temperature cyclic CO2 capture

2022; Elsevier BV; Volume: 274; Linguagem: Inglês

10.1016/j.enconman.2022.116461

1879-2227

Mohammad Heidari, Seyed Borhan Mousavi, Farhad Rahmani, Peter T. Clough, Serap Özmen,

Adsorption and Cooling Systems

Herein, for the first time, we employed three minor concentrations of Carbon Nanotubes (CNT), 2.5, 5, and 10 wt.%, as an auxiliary additive to boost the textural and structural features and CO2 capture potential of sol–gel-derived CaZrO3-CaO adsorbents. The corresponding xerogels were developed with 15/1 and 30/1 Ca/Zr molar ratios to minimize the required amount of prohibitive Zr-based precursor. For both types of CaZrO3-CaO xerogels, 5 wt.% of CNT was recognized as the most efficient amount. In addition to 15.84 and 33.1% reduction in CaO crystallite sizes, 50.57 and 90.55% increments in pore volume values were reported for CaO-based adsorbents developed with 15/1 and 30/1 Ca/Zr molar ratios, respectively. Over 15 cycles under harsh CO2 capture conditions, the total amount of captured CO2 for both abovementioned types of CaO-CaZrO3 xerogels raised from 2.01 and 1.96 to 2.92 and 3.01 g CO2/g adsorbent, sequentially. CaZrO3-promoted CaO nanoadsorbents merged with 5 wt.% CNT showed the ultimate CO2 capture capacity of 0.164 and 0.149 g CO2/g adsorbent for xerogel prepared with 15/1 and 30/1 M ratios of Ca/Zr, respectively. Even though the xerogel containing a Ca/Zr molar ratio of 15/1 showed the best sorption durability and ultimate capture capacity, CNT more significantly affects the CaO-based xerogel developed with a Ca/Zr molar ratio of 30/1. It can be deduced that the low content of CNT notably contributes to develop highly efficient and fluffy-like promoted xerogels containing minor concentrations of CaZrO3 species.