The diffusion coefficient of C3–C8 normal paraffins in 5A zeolite channels from the simulation ranged from 4.22 × 10−10 cm2/s to 4.68 × 10−14 cm2/s, indicating a slow mass transfer process. In addition, the diffusion rate becomes apparently slower with the increasing carbon numbers of the examined paraffins. In order to improve the adsorption separation efficiency of for n-paraffins, 5A zeolites with mesoporous structures were synthesized by hydrothermal method with the dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride as the template agent. Porosity and pore size distribution analysis demonstrated that micropores with the diameter of 0.5 nm were connected with 7–13 nm mesopores in the synthesized samples. The formation of hierarchical pore structure and change of surface morphology of zeolite particles could be controlled by the concentration of [3-(trimethoxysilyl)propyl] ammonium chloride used in the synthesis. The normal paraffin/cyclohexane solutions were used to investigate the adsorption kinetics of pentane, hexane, and heptane on the synthesized 5A zeolites. When the [3-(trimethoxysilyl)propyl] ammonium chloride concentration is 0.01%, the liquid phase diffusion coefficients of n-paraffins in the hierarchical 5A zeolite are 4–48 times larger than those in the microporous 5A zeolite. Our work demonstrates that the diffusion behavior and adsorption kinetics could be greatly improved by introducing mesoporosity into the pore structure of 5A zeolites.

中文翻译：

---

合成分级5A沸石以提高正链烷烃的分离效率

C3-C8 正构烷烃在 5A 沸石通道中的扩散系数从 4.22 × 10−10 cm2/s 到 4.68 × 10−14 cm2/s，表明传质过程缓慢。此外，随着被测石蜡碳原子数的增加，扩散速度明显变慢。为了提高对正链烷烃的吸附分离效率，以二甲基十八烷基[3-(三甲氧基甲硅烷基)丙基]氯化铵为模板剂，采用水热法合成了具有介孔结构的5A沸石。孔隙率和孔径分布分析表明，合成样品中直径为 0.5 nm 的微孔与 7-13 nm 的中孔相连。沸石颗粒分级孔结构的形成和表面形貌的变化可以通过合成中使用的[3-(三甲氧基甲硅烷基)丙基]氯化铵的浓度来控制。正构烷烃/环己烷溶液用于研究戊烷、己烷和庚烷在合成的 5A 沸石上的吸附动力学。当[3-(三甲氧基甲硅烷基)丙基]氯化铵浓度为0.01%时，分级5A沸石中正构烷烃的液相扩散系数比微孔5A沸石大4-48倍。我们的工作表明，通过将介孔性引入 5A 沸石的孔隙结构，可以大大改善扩散行为和吸附动力学。正构烷烃/环己烷溶液用于研究戊烷、己烷和庚烷在合成 5A 沸石上的吸附动力学。当[3-(三甲氧基甲硅烷基)丙基]氯化铵浓度为0.01%时，分级5A沸石中正构烷烃的液相扩散系数比微孔5A沸石大4-48倍。我们的工作表明，通过将介孔性引入 5A 沸石的孔隙结构，可以大大改善扩散行为和吸附动力学。正构烷烃/环己烷溶液用于研究戊烷、己烷和庚烷在合成 5A 沸石上的吸附动力学。当[3-(三甲氧基甲硅烷基)丙基]氯化铵浓度为0.01%时，分级5A沸石中正构烷烃的液相扩散系数比微孔5A沸石大4-48倍。我们的工作表明，通过将介孔性引入 5A 沸石的孔隙结构，可以大大改善扩散行为和吸附动力学。分级5A沸石中正构烷烃的液相扩散系数比微孔5A沸石大4-48倍。我们的工作表明，通过将介孔性引入 5A 沸石的孔隙结构，可以大大改善扩散行为和吸附动力学。分级5A沸石中正构烷烃的液相扩散系数比微孔5A沸石大4-48倍。我们的工作表明，通过将介孔性引入 5A 沸石的孔结构中，可以大大改善扩散行为和吸附动力学。