Energy-efficient CO₂/C₂H₂ separation by membranes is critical for producing acetylene by partial combustion of natural gas. Separating CO₂ and C₂H₂ by membranes is challenging because they have the same kinetic diameter and similar dimensions. Here we demonstrate for the first time high-silica chabazite (CHA) zeolite membranes with surprisingly high CO₂ selectivity over C₂H₂. Both unary permeation and binary mixture permeation data demonstrated consistent high CO₂ permselectivity >30. Equilibrium adsorption isotherms indicate only a slight adsorption selectivity for C₂H₂, implying that a high diffusion selectivity for CO₂ is required for the effective separation. The dynamic uptake data, however, points to slight C₂H₂ diffusion selectivity in CHA zeolite crystals. Hypotheses are proposed to explain the inconsistency between crystal and membrane diffusion results.

通过膜实现节能的CO ₂ /C ₂ H ₂分离对于通过天然气部分燃烧生产乙炔至关重要。通过膜分离CO ₂和C ₂ H ₂具有挑战性，因为它们具有相同的动力学直径和相似的尺寸。在这里，我们首次证明了高硅菱沸石（CHA）沸石膜相对于C ₂ H _{2具有令人惊讶的高CO 2选择性}。一元渗透和二元混合物渗透数据均表现出一致的高CO ₂选择性渗透率>30。平衡吸附等温线表明对 C 仅具有轻微的吸附选择性₂ H ₂ ，这意味着有效分离需要对CO ₂具有高扩散选择性。然而，动态吸收数据表明CHA 沸石晶体中存在轻微的C ₂ H _{2扩散选择性。}提出假设来解释晶体和膜扩散结果之间的不一致。