Four electrically neutral framework porous (AlPO) molecular sieves, UiO-7, AlPO₄-33, AlPO₄-17, and AlPO₄-18, as all-silicon molecular sieve isoelectronic analogues, have been synthesized and studied with regard to their performance in CH₄/N₂ adsorption and separation. Experimental results have shown that UiO-7, with the topological type ZON, has the lowest Brunauer–Emmett–Teller (BET) surface area, but exhibits the highest CH₄ adsorption capacity of 0.82 mmol/g and the highest adsorption selectivities of 4.4 (50:50, v/v) and 4.2 (20:80, v/v) among the four materials. BET surface area has been evaluated from N₂ adsorption and desorption isotherms at 77 K, and the average pore sizes of the four materials have been calculated on the basis of a density functional theory (DFT) model. Interestingly, the CH₄ adsorption capacity and adsorption selectivity have been found to first increase and then decrease with increasing average pore size of the four AlPO materials (AlPO₄-18: 0.56 nm, AlPO₄-17: 0.69 nm, UiO-7: 0.77 nm, AlPO₄-33: 0.88 nm). Compared with the data of activated carbon material that also has no surface adsorption sites, it is found: They were maximized when the average pore size of the adsorbent was close to 0.76 nm (diameter of CH₄, 0.38 nm). Theoretical calculations revealed that the suitable pore size of UiO-7, match better with CH₄ to provide stronger binding energy with CH₄ than other selected materials. And this result is verified by GCMC simulation. Thus, we infer that this is why UiO-7 shows the highest CH₄ selectivity. Mixed-gas breakthrough experiments and PSA simulations have further proved that UiO-7 may be used for CH₄/N₂ adsorption separation, and indeed is the best choice among the studied AlPO molecular sieves.

合成了四种电中性骨架多孔 (AlPO) 分子筛 UiO-7、AlPO ₄ -33、AlPO ₄ -17 和 AlPO ₄ -18 作为全硅分子筛等电子类似物，并对其性能进行了研究CH ₄ /N ₂吸附分离。实验结果表明，拓扑类型为 ZON 的 UiO-7 具有最低的 Brunauer-Emmett-Teller (BET) 表面积，但对 CH ₄的吸附容量最高，为 0.82 mmol/g，吸附选择性最高，为 4.4 ( 50:50, v/v) 和 4.2 (20:80, v/v) 四种材料。BET 表面积已从 N _2评估在 77 K 下的吸附和解吸等温线，并根据密度泛函理论 (DFT) 模型计算了四种材料的平均孔径。有趣的是，已经发现CH ₄吸附容量和吸附选择性随着四种AlPO材料（AlPO ₄ -18：0.56 nm，AlPO ₄ -17：0.69 nm，UiO-7： 0.77 纳米，AlPO ₄ -33：0.88 纳米）。与同样没有表面吸附位点的活性炭材料的数据相比，发现：当吸附剂的平均孔径接近0.76 nm（CH ₄, 0.38 纳米)。理论计算表明，合适的UiO-7孔径与CH 4 匹配得更好，与CH _4的结合能比其他选择的材料更强。并通过GCMC模拟验证了这一结果。因此，我们推断这就是 UiO-7 显示最高 CH ₄选择性的原因。混合气体突破实验和PSA模拟进一步证明UiO-7可用于CH ₄ /N ₂吸附分离，是目前研究的AlPO分子筛中的最佳选择。