Effect of SO x Adsorption on Layered Double Hydroxides for CO2 Capture

In this work, we investigate the effect of SO x on the performance of layered double hydroxide (LDH) derivatives used as adsorbent for CO2 capture. LDH derivatives such as layer double oxide (LDO) have shown great potential for high-temperature CO2 separation from flue gases. We found that even at low flue gas feed concentrations of SO x (0.1%), the sorption values were very high, reaching a maximum sorption capacity equivalent to 11.04% of the sorbent weight. Regeneration of LDO in pure helium resulted in regaining up to 58% of its original sorption capacity. Temperature cycling also revealed the irreversible nature of SO x sorption. In addition, regeneration after CO2/SO x and SO x /CO2 sorption experiments showed that SO x replaces CO2. SO x sorption over CO2 was favored due to the strong acid−base interactions between SO x and LDO, thus forming sulfites and sulfates. Hence, LDH derivatives for CO2 capture require a de-SO x unit operation upstream.