Limestone is a relatively abundant and low-cost material used for producing calcium oxide as a CO
2 adsorbent. However, the CO
2 capture capacity of limestone decreases rapidly after multiple carbonation/calcination cycles. To improve the CO
2 capture performance, we developed a process
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Limestone is a relatively abundant and low-cost material used for producing calcium oxide as a CO
2 adsorbent. However, the CO
2 capture capacity of limestone decreases rapidly after multiple carbonation/calcination cycles. To improve the CO
2 capture performance, we developed a process using limestone to transform the material into a rod Ca-based metal–organic framework (Ca-MOF) via a hydrothermal process with the assistance of acetic acid and terephthalic acid (H
2BDC). The structural formation of rod Ca-MOF may result from the (200) face-oriented attachment growth of Ca-MOF sheets. Upon heat treatment, a highly stable porous rod network with a calcined Ca-MOF-O structure was generated with a pore distribution of 50–100 nm, which allowed the rapid diffusion of CO
2 into the interior of the sorbent and enhanced the CO
2 capture capacity with high multiple carbonation–calcination cycle stability compared to limestone alone at the intermediate temperature of 450 °C. The CO
2 capture capacity of the calcined porous Ca-MOF-O network reached 52 wt% with a CO
2 capture stability of 80% after 10 cycles. The above results demonstrated that rod Ca-MOF can be synthesized from a limestone precursor to form a porous network structure as a CO
2 capture sorbent to improve CO
2 capture performance at an intermediate temperature, thus suggesting its potential in environmental applications.
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