Chinese Journal of Chemical Engineering ›› 2021, Vol. 29 ›› Issue (1): 131-134.doi: 10.1016/j.cjche.2020.07.015

• Separation Science and Engineering • Previous Articles     Next Articles

Desorption of Cl- from Mg-Al layered double hydroxide intercalated with Cl- using CO2 gas and water

Tomohito Kameda1, Hiroki Uchida1, Shogo Kumagai1, Yuko Saito1, Keiichi Mizushina2, Ichirou Itou2, Tianye Han2, Toshiaki Yoshioka1   

  1. 1 Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan;
    2 Kurita Water Industries Ltd., Nakano Central Park East, 4-10-1 Nakano, Nakano-ku, Tokyo 164-0001, Japan
  • Received:2020-03-16 Revised:2020-06-24 Online:2021-01-28 Published:2021-04-02
  • Contact: Tomohito Kameda

Abstract: Mg-Al layered double hydroxide intercalated with CO32- (CO3·Mg-Al LDH) is effective for treating HCl exhaust gas. HCl reacts with CO32- in CO3·Mg-Al LDH, resulting in the formation of Cl·Mg-Al LDH. We propose that CO2 can be used for the desorption of Cl- from Cl·Mg-Al LDH to regenerate CO3·Mg-Al LDH. Herein, we studied the desorption of Cl- from Cl·Mg-Al LDH by adding water to Cl·Mg-Al LDH and blowing CO2 into it. We also analyzed the effects of temperature and water addition speed on the desorption of Cl- from Cl·Mg-Al LDH. Our results show that the added water adhered to Cl·Mg-Al LDH and that CO2 in the gaseous phase was dissolved in this adhered water, thus generating CO32-. Therefore, anion exchange occurred between CO32- and Cl- in the Cl·Mg-Al LDH, thus desorbing Cl-.

Key words: Mg-Al layered double hydroxide, CO2 gas, Cl- desorption, Semi-dry method