In the zeolite family, the silicoaluminophosphate (SAPO)-34 zeolite has a unique chemical structure, distinctive pore size, adsorption characteristics, as well as chemical and thermal stability, and recently, has attracted much research attention. Increasing global carbon dioxide (CO2) emissions pose a serious environmental threat to humans, animals, plants, and the entire environment. This mini-review summarizes the role of SAPO-34 zeolite membranes, including mixed matrix membranes (MMMs) and pure SAPO-34 membranes in CO2 separation. Specifically, this paper summarizes significant developments in SAPO-34 membranes for CO2 removal from air and natural gas. Consideration is given to a variety of successes in SAPO-34 membranes, and future ideas are described in detail to foresee how SAPO-34 could be employed to mitigate greenhouse gas emissions. We hope that this study will serve as a detailed guide to the use of SAPO-34 membranes in industrial CO2 separation.

Silica nanochannel membranes, particularly those consisting of highly ordered and vertically aligned channels (designated as SNM for simplicity in this review), have recently emerged as a class of attractive nanomaterials, because of their controllable and tunable pore structure, large surface area, high selectivity, and permeability, as well as diverse promising applications. This review describes recent developments in the field of SNM and their applications in electrochemical analysis and molecular separation. We summarize and highlight (i) the synthesis and functionalization strategies; (ii) the basic properties with emphasis on the selectivity and permeability, and factors affecting them; (iii) electrochemical analysis based on the electrode-supported SNM in terms of electrostatic, hydrophobic extraction, size-exclusion, and anti-fouling effects; (iv) molecular separation using the flow-through SNM according to molecular properties (size, charge, and lipophilicity) and gated, rectified molecular transport. Finally, we present an outlook and perspective on the further applications of SNM in the relevant fields.