燃煤电厂尾部烟气经脱硫后，存在的痕量SO₂会导致钾基吸附剂CO₂吸附性能恶化。以结晶氯化铝为前驱体，采用溶胶-凝胶法制备K₂CO₃/Al₂O₃固体吸附剂，利用固定床反应系统，模拟烟气组分，在含SO₂(0、150、250、400 mg/m³)气氛下的CO₂吸附特性进行了吸附实验，结合BET、XRD表征手段，分析吸附剂孔隙结构和物质组成，采用DFT理论研究了SO₂对K₂CO₃/Al₂O₃(0001)吸附剂表面吸附CO₂的影响及机理。结果表明，在理想气氛中，钾基吸附剂CO₂累积吸附量为1.72 mmol/g，当反应气氛中存在150 mg/m³ SO₂时，钾基吸附剂与SO₂发生反应生成K₂SO₃，导致吸附剂的吸附量(1.38 mmol/g)降低了19.77%，SO₂质量浓度增至400 mg/m³，钾基吸附剂CO₂累积吸附量逐渐降至1.26 mmol/g，吸附剂吸附CO₂性能恶化，钾基吸附剂在7次循环后吸附量降为1.1 mmol/g，循环性能变差。CO₂、SO₂两种分子在K₂CO₃/Al₂O₃(0001)表面吸附位点均为Al-O桥位，H₂O分子的吸附位点为O顶位。K₂CO₃/Al₂O₃(0001)表面对SO₂的吸附作用大于H₂O和CO₂。H₂O和CO₂共吸附时CO₂分子中O-s轨道与H-s轨道重叠，使得2者在表面吸附时可以相互促进；SO₂分子由于其S、O原子p轨道活跃，与CO₂共吸附时，会优先抢占CO₂的吸附位点，抑制CO₂在表面的吸附。H₂O分子对K₂CO₃/Al₂O₃(0001)表面吸附SO₂的促进作用大于CO₂，H₂O的存在会加速SO₂与表面的反应，导致吸附剂表面对CO₂吸附能力变差。CO₂与H₂O共吸附于K₂CO₃/Al₂O₃(0001)表面时碳酸化反应机理为H₂O分子中H⁺和OH⁻，分别与${mathrm{CO}}_3^{2-} $和CO₂形成${mathrm{HCO}}_3^- $，反应能垒为1.12 eV，反应热为−1.47 eV。

After desulphurization, the trace amount of SO₂ in the tail gas of coal-fired power plant will lead to the deterioration of CO₂ adsorption performance of potassium-based adsorbent. Using crystalline aluminum chloride as precursor, the solid adsorbent K₂CO₃/Al₂O₃ was prepared by sol-gel method. The adsorption characteristics of CO₂ in SO₂ (0, 150, 250 and 400 mg/m³) atmosphere were simulated by fixed bed reaction system. Combined with the BET and XRD characterization methods, the pore structure and material composition of the adsorbent were analyzed. The influence of SO₂ on the surface adsorption of CO₂ by K₂CO₃/Al₂O₃(0001) was studied by using the DFT theory. The results showed that in the ideal atmosphere, the cumulative adsorption capacity of CO₂ of potassium adsorbent is 1.72 mmol/g. In the presence of 150 mg/m³ SO₂ in the reaction atmosphere, the potassium adsorbent reacts with SO₂ to form K₂SO₃, resulting in a 19.77% decrease in adsorption capacity (1.38 mmol/g). When the concentration of SO₂ increases to 400 mg/m³, the cumulative adsorption capacity of CO₂ of potassium-based adsorbent gradually decreases to 1.26 mmol/g, the adsorption performance of CO₂ of the adsorbent is deteriorated. The adsorption capacity of potassium-based adsorbent decreases to 1.1 mmol/g after seven cycles, and the cycle performance is deteriorated. The adsorption sites of CO₂ and SO₂ on the surface of K₂CO₃/Al₂O₃(0001) are Al-O bridge sites, and the H₂O molecules are O top sites. The adsorption of SO₂ on K₂CO₃/Al₂O₃(0001) surface is greater than that on H₂O and CO₂. When H₂O and CO₂ are co-adsorbed, the O-s orbitals and H-s orbitals overlap in the CO₂ molecules, so that the two can promote each other during surface adsorption. Due to the active p orbitals of S and O atoms, the SO₂ molecules preferentially preempt the adsorption site of CO₂ and inhibit the adsorption of CO₂ on the surface when co-adsorbed with CO₂. The catalytic effect of H₂O molecules on the adsorption of SO₂ on the surface of K₂CO₃/Al₂O₃(0001) is greater than that of CO₂. The presence of H₂O will accelerate the reaction between SO₂ and the surface, leading to the deterioration of the adsorption capacity of CO₂ on the surface of the adsorbent. When CO₂ and H₂O are co-adsorbed on K₂CO₃/Al₂O₃(0001) surface, the carbonation mechanism is H⁺ and OH⁻ in H₂O molecules, which forms ${mathrm{HCO}}_3^- $ with ${mathrm{CO}}_3^{2-} $ and CO₂ respectively. The reaction energy barrier is 1.12 eV, and the reaction heat is −1.47 eV.