Potential CO2 capture in one-coat limestone mortar modified with Mg3Al–CO3 calcined hydrotalcites using ultrafast testing technique

Abstract

• HT C2500 worsened the compressive strength of one-coat limestone mortar. • HT C2500 reduced the carbonation reaction of portlandite. • The CO 2 capture capacity increased by 8.52% upon addition of 5% HT C2500. • One m 2 of one-coat mortar modified with 5% of HTC2500 cleans 5540 m 3 of air. • An ultrafast method to quantify the maximum CO 2 capture capacity was presented. The objective of this work is to quantify the CO 2 capture capacity of an industrial one-coat limestone mortar containing different percentages of calcined Mg 3 Al–CO 3 hydrotalcite (HT C2500) added (0, 2.5, and 5%) in different hardening environments (with different concentrations of CO 2 ). The maximum CO 2 capture capacity (calculated by thermogravimetric analysis) for 0, 2.5, and 5% of added HT C2500 were 1127, 1143, and 1223 g·m −2 (as rendering), respectively. This amount of CO 2 is approximately one-third of that emitted during the manufacture of the cement used for this mortar. The addition of calcined hydrotalcite worsened the compressive strengths obtained in all the hardening environments studied. A 5% of calcined hydrotalcite increased the CO 2 capture capacity by 8.52% with respect to the reference mortar. Ultrafast testing method (using CO 2 isotherms at high pressure) has been proposed to quantify the CO 2 capture capacity in very short period of time. A slight modification in the dosage of calcined hydrotalcite in an industrial one-coat mortar can contribute to mitigating climate change.