Treatment of HCl gas by cyclic use of Mg–Al layered double hydroxideintercalated with CO32-

Özet

Mg–Al layered double hydroxide intercalated with CO32−(CO3•Mg–Al LDH) was investigated for treating HClgas generated from industrial plants. Specifically, we compared the performance of CO3•Mg–Al LDH and highlyreactive Ca(OH)2, and they showed approximately the same HCl removal capacity in conventional methods. ForHCl gas (300 ppm, linear velocity 1.0 m/min) at 170 °C, the removals by CO3•Mg–Al LDH at Mg/Al = 2.0 and 4.0were 93.5% and 93.1% after 90 min, respectively, while that by Ca(OH)2was 93.3%. This indicates thatCO3•Mg–Al LDH could be used in place of slaked lime to treat HCl. After the reaction, the CO3•Mg–Al LDH couldbe regenerated from Cl•Mg–Al LDH in a CO32−anion exchange reaction. Finally, we studied the cyclic use ofCO3•Mg–Al LDH by combining HCl treatment with regeneration in Na2CO3solution. At least 3 adsorption-desorption cycles could be carried out for CO3•Mg–Al LDH at Mg/Al = 2.0 and 4.0, with thefinal performancebeing 86% and 94% of the initial value, respectively.