Mg - Al layered double hydroxide intercalated with CO32- and its recyclability for treatment of SO2

Mg - Al layered double hydroxide intercalated with CO32- (CO3 center dot Mg - Al LDH) was successfully used to remove SO2 from a gas mixture at 140, 170, and 200 degrees C. The removal of SO2 with CO3 center dot Mg - Al LDH occurred via surface adsorption of SO2 and anion exchange between CO32- in the interlayer of Mg - Al LDH and SO2 from the gas mixture. The removal of SO2 followed the order of Ca(OH)(2) > CO3 center dot Mg - Al LDH (Mg/Al = 2) > CO3 center dot Mg - Al LDH (Mg/Al = 4). The removal of SO2 also followed the order of CO3 center dot Mg - Al LDH > Mg (OH)(2) > SO4 center dot Mg - Al LDH. CO3 center dot Mg - Al LDH was regenerated from SO4 center dot Mg - Al LDH using a Na2CO3 solution through anion exchange between SO42- and CO32-, leading to its recyclability for removal of SO2 from a gas mixture three times, demonstrating the feasibility of recycling the material.