Cu-BTC and Zeolite-5A-Modified Cu-BTC MOFs for High-Pressure and Moderate-Temperature H₂ Purification

Hydrogen (H2) is considered to be a key component in the transition to clean energy economies. Improving the production efficiency and lowering the cost of H2 purification remain important research focuses as industry transitions to low carbon dioxide (CO2) emission H2 pathways. The aim of this work is the development of metal–organic framework (MOF)-based H2 purification materials to be used at high pressure and moderate temperatures to both reduce syngas cooling and H2 compression demands, thereby significantly lowering operating costs. Here, we developed two Cu-benzene-1,3,5-tricarboxylate (Cu-BTC) adsorbents, labeled as A1 and A2, incorporating some modifications from those previously explored in the literature. The study investigated the influence of variables such as mixing time of precursor solutions, reaction temperature, and reaction duration on the performance of the synthesized adsorbents. The results indicated that optimal stability for adsorbent A1 was attained through premixing precursor solutions for a specific duration while maintaining moderate levels of reaction temperature and duration. Subsequently, we incorporated 10 wt % zeolite-5A into the most effective Cu-BTC sample (A3) and conducted further testing. All synthesized MOFs underwent characterization through X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Single-component adsorption isotherms for CO2, methane (CH4), and carbon monoxide (CO) were measured at 30 °C to assess their equilibrium adsorption capacities over the respective adsorbents. The findings indicated that A3 demonstrated superior performance compared to commercial zeolite-5A, possibly attributed to the development of new mesopores at the interface of Cu-BTC and zeolite. However, A1 still exhibited higher gas uptake compared to A3, due to its high surface area and total pore volume. The optimal regeneration temperature for the A1 sample was experimentally determined to be 150 °C, providing efficient removal of adsorbed gases without causing damage to the material. Furthermore, high-pressure adsorption isotherms, extending up to 30 bar (g), were employed to evaluate the CO2 gas uptake performance of various adsorbents. A1 was subjected to testing under 50 and 70 °C and high-pressure conditions to assess its suitability for industrial applications. Overall, the findings of this study suggest that the A1 adsorbent is a promising candidate for higher-pressure and moderate-temperature H2 purification processes.