Effect of SOx adsorption on layered double hydroxides for CO2 capture

In this work, we investigate the effect of SOx 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 SOx (0.1%), the sorption values were very high, reaching a maximum sorption capacity equivalent to 11.04% of the sorbent weight. Regeneration of LIDO in pure helium resulted in regaining up to 58% of its original sorption capacity. Temperature cycling also revealed the irreversible nature of SOx sorption. In addition, regeneration after CO2/SOx and SOx/CO2 sorption experiments showed that SOx replaces CO2. SOx sorption over CO2 was favored due to the strong acid-base interactions between SOx and LDO, thus forming sulfites and sulfates. Hence, LDH derivatives for CO2 capture require a de-SOx unit operation upstream.