Characteristics of Na–Mg double salt for high-temperature CO2 sorption

Abstract

Abstract A novel high temperature CO 2 sorbent, Na–Mg double salt, was prepared by a precipitation method. Thermogravimetric analysis was used to measure the thermal stability and to investigate the CO 2 sorption behavior at high temperatures. The prepared Na–Mg double salt showed unique CO 2 sorption characteristics in the temperature range of 300–500 °C. A remarkably high CO 2 sorption uptake of 3.48 mol/kg (15.3 wt%) was measured at 375 °C and was maintained during repeated sorption/desorption cycles. Electronic microscopy and X-ray diffraction were used to determine the Na–Mg double salt morphology and structure, respectively. The elemental composition ratio in the Na–Mg double salt was characterized by inductively coupled plasma atomic emission spectroscopy and an elemental analysis. In situ X-ray diffraction analysis revealed that the CO 2 sorption mechanism was based on the reaction of CO 2 with MgO and Na 2 CO 3 in the double salt to form Na 2 Mg(CO 3 ) 2 . In addition to the high CO 2 sorption uptake and good cyclic stability, the Na–Mg double salt showed exceptionally fast sorption and desorption.