RESUMEN
The objective of this study is to introduce Cu into SnO2 sorbent for improving its COS adsorption capacity. Cu-doped SnO2 adsorbents were synthesized using a conventional sol-gel method with citric acid. X-ray diffraction studies revealed that up to 0.4 mol of Cu ions were well-inserted within the SnO2 framework. Scanning electron microscopy images confirmed that the addition of Cu ions reduced the particle size of the SnO2 sorbents. Additionally, it led to an increase in the Brunauer-Emmett-Teller surface area of the sorbents. The COS adsorption tests were carried out in the temperature range of 300-400 °C with a gas hourly space velocity of 8,500 h-1. It was found that Cu0.6SnO2 displayed higher COS adsorption capacity than the sorbents of other compositions, and the breakthrough time and COS adsorption capacity on it at 400 °;C were 170 min and 4.87 mg/g, respectively. X-ray photoelectron spectroscopy results indicated that the Cu2+ ions in the CuxSnO2 adsorbent converted into CuS by binding to the S2- ions in COS gas, while the remaining CO segments combined with the Sn atoms in SnO2 and then are adsorbed as SnCO. Overall, this study showed that the hard-soft acid-base rule is better followed in the Cu0.6SnO2 adsorbent than in the SnO2 adsorbent and that the adsorption is more stable.