Understanding rapid thermal swing adsorption of carbon dioxide with moisture-tolerant sorbent coatings

Four types of CO 2 sorbents - Zn-triazole framework, ZIF-8-TEPA, functionalized silica gel, and amino-functionalized resin - were successfully coated onto heat exchanger surfaces without loss of CO 2 capacity using cellulose-based binder. Thin coatings of ZIF-8-TEPA (0.38 mm thickness) were able to cycle up to 0.2 mol CO 2 m − 2 (30 g CO 2 kg − 1 ) during thermal swings between 25 – 75 ° C with 2 min between switches, while coatings from Zn-triazole MOF (0.46 mm thickness) could reach 0.3 mol CO 2 m − 2 (40 g CO 2 kg − 1 ) during the same cycles. Low regeneration temperature reduces degradation and enables the use of waste heat, making rapid thermal swing adsorption (RTSA) more cost-effective. Modelling of the coupled heat and mass transfer accurately captures CO 2 uptake dynamics and confirms the efficacy of rapid thermal swing adsorption even under humid conditions. Furthermore, this model elucidates the critical influence of micropore dimensions, particle size, and hierarchical pore architecture on facilitating efficient mass transfer, thereby informing the rational selection and design of sorbent films for CO 2 capture using rapid thermal swing adsorption. • Rapid thermal swing adsorption with 25–75 °C temperature cycles under the wet CO 2 is possible. • Newly developed coatings can effectively cycle CO 2 during 2-min rapid thermal swing adsorption. • Carbon dioxide adsorption rate is significantly faster than for water under the wet flue gas. • Microporous sorbents need to have crystallite sizes below 1 micrometer for rapid adsorption.