NaBr-Enhanced CaO-Based Sorbents with a Macropore-Stabilized Microstructure for CO2 Capture

Abstract

Calcium looping process (CaLP) is well-considered as a cost-effective scenario for trapping CO2 from flue gas. However, the CO2 capture capacity of natural CaO-based sorbents spoils rapidly over long-term cycles. In this work, NaBr was introduced to enhance the cyclic CO2 capture capacity of CaO sorbents. The NaBr-modified CaO showed an improved activity and durability for carbonation. After 100 cycles, the “NaBr/CaO-10/100” maintained a capacity of 0.202 g CO2/g sorbent, which was about 185% higher than that of unmodified CaCO3 precursor. The mechanism of enhancement was analyzed by a simultaneous thermal analyzer (STA), in situ X-ray powder diffraction (in situ XRD) instrumentation, an inductively coupled plasma optical emission spectrometer (ICP-OES), a field emission scanning electron microscope coupled energy dispersive X-ray spectrometer (FSEM-EDS), and N2 physical absorption analysis, and the results showed that the modified sorbent formed a well-linked macropore structure, which was relatively sta...