Separation of Gas Mixture of H₂ and CO₂ by Nanopromoter-Enhanced Gas Hydrate Formation

Traditional coal burning emits a large amount of pollutants, including sulfur dioxide (SO₂), nitrogen oxides, and carbon dioxide (CO₂), severely contaminating the environment and exacerbating global warming. In contrast, integrated gasification combined cycle (IGCC) technology, with highly efficient and clean characteristics, significantly reduces pollutant emissions and has a positive impact on environmental protection. It is a simple and effective method to obtain hydrogen (H₂) by purifying IGCC fuel gas with the main components of H₂ and CO₂. Thermodynamic promoter tetra-n-butyl ammonium bromide (TBAB) is widely used in gas separation of IGCC fuel gas by the hydrate method. In this work, polystyrene nanoparticles grafted by -SO₃^- groups (-SO₃^-@PSNS) and grafted by -SO₃^- groups and Ag particles (Ag&-SO₃^-@PSNS) are used together with TBAB, respectively, to promote the formation of hydrate. The gas separation effect and growth morphology are studied. The experimental results demonstrate that the incorporation of nanopolymer can significantly enhance the separation efficiency (SFr) of a mixture of H₂ and CO₂. Notably, compared to the reaction solution without nanopolymer, 2 mmol/L -SO₃^-@PSNS exhibits the most pronounced effect on gas separation, resulting in an impressive gas consumption of 0.755 ± 0.323 mmol/L and a remarkable increase in the separation factor (SF) by 106%. After loading silver nanoparticles, the promoting effect of Ag&-SO₃^-@PSNS is further strengthened. Under Ag&-SO₃^-@PSNS-20%, the gas consumption reaches the maximum of 0.775 ± 0.003. Under Ag&-SO₃^-@PSNS-30%, the SF rises from 32.79 ± 6.27 to 37.92 ± 7.19, indicating an impressive increment of 15.80%. The visualized droplet experiment shows that Ag&-SO₃^-@PSNS significantly promotes the nucleation of hydrate and the growth rate of hydrate.