Carbonate-intercalated Mg–Al layered double hydroxides (CO3·Mg–Al LDHs) are examined as a means of sequestering gaseous pollutants, such as HCl, NOx, and SOx, which are bound to afford X·Mg–Al LDH (X = Cl, SO4, or NO3). In view of the fact that the common regeneration method of CO3·Mg–Al LDH (agitation in aqueous Na2CO3) poses a number of problems, we herein develop a new method of regenerating CO3·Mg–Al LDH by treatment of X·Mg–Al LDH with gaseous CO2 under neutral or alkaline conditions. The desorption of X is shown to follow the intraparticle diffusion model, featuring the diffusion of CO32− in between LDH layers as the rate-determining step. Given the importance of LDHs for wastewater treatment and gaseous pollutant removal, the obtained results pave the way to the efficient utilization of these adsorbents and contribute to the development of next-generation decontamination techniques.
- Anion desorption
- CO gas
- Mechanism elucidation
- Mg–Al layered double hydroxide