Adsorption separation of low-concentration CO using Ni-S adsorbent supported on activated carbon

• Ni-S/AC exhibited notably high CO adsorption capacity and selectivity at low CO concentrations. • Low-concentration CO was effectively separated from simulated coke oven gas (5% CO) using Ni-S/AC. • Adsorbed CO was desorbed at mild temperatures below 100 °C. • H 2 regeneration was required to remove surface oxygen generated from CO dissociation. • Repeated adsorption–desorption breakthrough experiments confirmed the stability of the adsorbent. The recovery of low-concentration CO has both economic and environmental significance. However, due to the lack of efficient separation technologies, low-concentration CO is often combusted, resulting in substantial CO 2 emissions. Here, we investigated the adsorption separation of low-concentration CO using Ni-S supported activated carbon (Ni-S/AC). Ni-S/AC exhibited remarkably high CO adsorption capacity and selectivity, even at low CO concentrations. Breakthrough experiments revealed that Ni-S/AC selectively adsorbed and enriched CO from simulated coke oven gas (COG) containing 5 % CO. While most of the adsorbed CO was desorbed at mild temperatures below 100 °C, H 2 regeneration was required due to the partial dissociative adsorption of CO. Repeated adsorption–desorption breakthrough experiments demonstrated the stability of the adsorbent. This study highlights the potential of Ni-S/AC as an effective adsorbent for CO recovery from low-concentration CO mixtures, offering a promising approach for the utilization of by-product gases such as COG.