Zeolites are widely employed in the industrial drying of gases by Temperature Swing Adsorption (TSA). In a typical TSA process, the adsorbent is packed in a fixed bed, which is sequentially subjected to a “cold” feed (adsorption) and a hot flush (desorption). Due to the hydrothermal stress, adsorbents may suffer from reduced drying capacity in long-term service. The aim of this work is to assess the impact of thermal aging of two zeolite materials (LTA and CHA) having similar pore openings but different Si/Al ratios. We examined how simulated thermal aging affected porous texture, coke deposition and water vapor adsorption equilibrium and kinetics. Both zeolites showed reduced uptake of probe molecules (N₂ at 77 K and CO₂ at 273 K) and water vapor (303 K) when subjected to simulated thermal aging. In Fourier-Transform Infrared Spectroscopy (FTIR) analyses, only the aged LTA zeolite showed bands related to the presence of aromatic compounds. Water vapor adsorption uptake decreased 28.6% and 18.4% for LTA and CHA at 30 mbar, respectively. Kinetic studies indicate a reduction in water diffusion coefficient after the aging cycles. Although LTA has a significantly higher affinity for water as compared to CHA, the latter is much more resistant to hydrothermal aging with comparatively faster water diffusion.

沸石广泛用于通过变温吸附 (TSA) 对气体进行工业干燥。在典型的 TSA 工艺中，吸附剂填充在固定床中，然后依次进行“冷”进料（吸附）和热冲洗（解吸）。由于水热应力，吸附剂在长期使用中可能会降低干燥能力。这项工作的目的是评估两种沸石材料（LTA 和 CHA）的热老化影响，它们具有相似的孔隙开口但不同的 Si/Al 比。我们研究了模拟热老化如何影响多孔结构、焦炭沉积和水蒸气吸附平衡和动力学。两种沸石对探针分子（77 K 时的N ₂和 CO ₂在 273 K) 和水蒸气 (303 K) 下进行模拟热老化。在傅里叶变换红外光谱 (FTIR) 分析中，只有老化的 LTA 沸石显示出与芳香族化合物存在相关的谱带。在 30 毫巴下，LTA 和 CHA 的水蒸气吸附量分别降低了 28.6% 和 18.4%。动力学研究表明，老化循环后水扩散系数会降低。尽管与 CHA 相比，LTA 对水的亲和力明显更高，但后者对水热老化的抵抗力要强得多，水的扩散速度也相对较快。