Hydrogen Valorization from Industrial Waste Streams Using Matrimid/LaNi₅ Mixed Matrix Hollow Fiber Membranes

The valorization of industrial residual gas streams through hydrogen recovery is a key strategy for improving process efficiency and reducing environmental impact. In this context, the practical application of polymeric-based membranes, relies on enhancing the selectivity-permeability trade-off, typically achieved through the incorporation of optimized fillers, while ensuring scalability. In this work, LaNi₅, a hydrogen storage intermetallic compound, was incorporated into a polyimide matrix to increase the membrane affinity toward H₂ and processed in a hollow fiber configuration. The mixed matrix hollow fiber membranes were evaluated through gas permeation experiments combined with modeling under operating conditions representative of industrial residual gas streams. The use of LaNi₅ at 5 wt %, uniformly distributed along the fibers as confirmed by SEM-EDX analysis, delivered 2.5 times higher H₂ permeance (38.4 GPU) compared to pristine Matrimid fibers. The favorable absorption of H₂ on LaNi₅ resulted in enhanced selectivity with a value of 6.2 for H₂/CO₂ and nearly 65 for bulk compounds (H₂/N₂, H₂/CH₄ and H₂/CO). Furthermore, the membranes exhibited stable performance over approximately 580 h of continuous operation. Finally, the model of hydrogen permeation through the hollow fiber membrane that accounts for the contribution of the polymer, and the filler showed a good agreement with the experimental data, as illustrated in the parity plot, where deviations fall within the predefined ±15% threshold. Thus, this work advances the development of high-performance membranes for hydrogen recovery from waste gas streams while supporting process scale-up through hollow fiber membrane implementation.