Preparation of PEBA/N, S co-doped porous carbon sphere mixed matrix membrane for CO2 separation

In order to obtain high-performance mixed matrix membrane to effectively capture CO2 in flue gas, this paper designed a N,S co-doped porous carbon sphere with excellent diffusion and adsorption selectivity for CO2 as an additive to achieve the efficient separation of CO2/N2 from flue gas. Glucose with rich oxygen groups as the carbon source and thiourea as nitrogen and sulfur source are selected to prepare the nitrogen and sulfur co-doped carbons (NSC) by hydrothermal method. The porous structure of NSPC is produced by the activation of NSC with KOH. FTIR, XRD and BET tests indicate the successful synthesis of NSPC, which has high specific surface area and microporosity. The optimal ratio of glucose to thiourea, the optimal ratio of NSC to KOH in the synthesis of NSPC, the effect of NSPC content, feed pressure, test temperature on the performance of the membrane are studied. It proves that the nitrogen, sulfur-containing CO2 affinity sites and micropores in NSPC have beneficial effects on the gas separation performance of the membrane. The results show that when the NSPC content is 3%(mass), the performance of membrane is the best at 25℃ and 0.2 MPa. The CO2 permeability is 589 Barrer, and the CO2/N2 selectivity is 64. The performance of the membrane in the mixed gas is slightly lower than that in the pure gas, and it can remain stable for 360 h, which has good industrial application prospects. © 2021, Editorial Board of CIESC Journal. All right reserved.