Research on the Process for Removing Heat-Stable Salts from Organic Amine Absorbents via Electrodialysis

The use of organic amine absorbents in CO2 capture technologies is highly significant. The widespread application of this technique is limited by the heat-stable salts (HSSs) produced during the cyclic absorption–desorption process. This research focused on the HSS removal process using electrodialysis technology and systematically examined the effects of operating voltage, initial concentration, pH, current density, the ratio of liquid volume in the enriched chamber to that in the diluting chamber, and the type of ion-exchange membrane on desalination efficiency, energy consumption, and amine loss. An increase in both voltage and initial concentration significantly enhances the rate of water migration. The rate of ion migration is observed to follow the order of Cl− > SO42− > F− in a homogeneous membrane, while in a heterogeneous membrane, the order is SO42− > Cl− > F−. The optimal operating voltage is 10 V, with a pH level of 8 resulting in the highest SO42− removal efficiency. An industrial scenario validated the optimized process conditions, which balanced energy consumption with desalination efficiency. This methodology is essential not only for providing a viable solution for the industrial purification of organic amines but also for promoting the environmentally sustainable development of carbon capture technologies.