(406b) Selective Separation of CO from CO2 By Cu Cl Based Adsorbents

The separation of carbon monoxide (CO) from gaseous mixtures containing carbon dioxide (CO₂) by different adsorbents has been studied. Experimental results from literature had shown that most adsorbents are CO₂ selective and the CO uptake and selectivity over different adsorbents is not sufficient.

In this study, adsorbents were developed through adsorbent modifications with Copper (II) chloride (CuCl₂) as precursor to improve CO uptake and selectivity. Herein, the adsorbents were prepared using two different approaches: through the thermal monolayer dispersion method and through a modified Polyol method. The experimental adsorption isotherms of pure CO and CO₂ in studied adsorbents including activated carbon, metal organic framework and ordered mesoporous silica were performed at 298 K and pressures up to 20 bar. Results showed that the CO adsorption capacity improved significantly while CO₂ adsorption decreased in modified adsorbents. The strong Ï€ complexation between Cu⁺ ions and CO have proven to enhance the CO adsorption uptake and selectivity while reducing the CO₂ uptake. The CO selectivity achieved was 4.3 in modified activated carbon CuCl/Xtrusorb compared to 0.2 before modification at 100 KPa and 298 K. Moreover, copper loading of 7mmol/g reached highest CO selectivity compared to 3 and 5 mmol/g copper loading. Sample characterizations were performed by X-Ray diffraction (XRD) and N₂ adsorption at 77 K for BET surface area analysis. The characterization results suggested that CuCl₂ salt is completely reduced to CuCl dispersed on the surface of the adsorbents. Adsorption isotherms were well described by dual site Langmuir and Sips models.