A mini-review of the current progress and future challenges of zeolites for hydrogen isotopes separation through a quantum effect

Deuterium or tritium, which are rare isotopologues of hydrogen, are in high demand across various industries; thus it is crucial to develop a separation technology for hydrogen isotopologues that is both efficient and cost-effective. However, conventional separation methods like 20 K cryogenic distillation have low separation performance (separation factor less than 1.5) and require a significant amount of energy due to their nearly identical physicochemical attributes. And thus, there has been an effort to find a novel separation strategy. In pursuit of this goal, researchers have explored crystalline porous materials utilizing the recently highlighted kinetic quantum sieving (KQS) and chemical affinity quantum sieving (CAQS) techniques. In this context, we will focus on zeolites, which are considered the most widely available crystalline porous material. They are known for exhibiting high thermal and chemical stability, as well as longevity and reusability, making them superior to other porous materials like Metal-Organic Frameworks (MOF). The focus will be on previous studies conducted on zeolites for hydrogen isotopologues separation, with specific emphasis on KQS and CAQS. It was discovered that these studies were mainly limited to certain types of typical zeolites, such as CHA and MFI. Additionally, the mechanisms used were biased toward CAQS due to the presence of metal cations in most zeolites. Furthermore, the previous research did not possess an enough comprehensive understanding of the performance of zeolites. Therefore, this mini-review aims to outline effective strategies that can overcome these limitations and achieve breakthroughs in hydrogen isotopologues separation, leading to commercialization and scientific advancements.