SBA-15/CMS composite membrane for H2 purification and CO2 capture: Effect of pore size, pore volume, and loading weight on separation performance

• The texture and surface acidity of the SBA-15 filler were altered using an aging procedure.
• The carbon matrices and the SBA-15 filler have good adherence due to the Si–OH bonds.
• The total pore volume of the SBA-15 filler affected the performance.
• Excellent H2 and CO2 permselectivities were obtained with the incorporation of the SBA-15 filler.

This study investigated the effect of the SBA-15 filler texture on the gas separation performance of polyphenylene oxide (PPO)-derived composite CMS membranes, specifically on hydrogen separation and carbon capture. Four types of SBA-15 fillers were synthesized via the template method using different aging temperatures. The results indicate that the pore size, pore volume, and Si–OH groups of the SBA-15 silica affected the final amorphous carbon structure, which led to better gas separation performance. SBA-15 prepared at 120 °C had better separation performance than SBA-15 prepared at the other aging temperatures. The silica structures create void spaces and nanopore channels in the resultant carbon film and cross-link with polymer chains, resulting in excellent ideal separation performance. The effect of the SBA-15 loading weight, which was varied from 0.025 to 0.4 wt%, was also investigated. The results show that the H2 permeability through PPO/SBA-15 remarkably increased from 319 to 2420 Barrer [1 Barrer = 1 × 10−10 cm3 (STP) cm/(cm2 s cmHg)] with increasing loading weight from 0.025 to 0.1 wt%.

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