Efficient formation of methane hydrate in the sulfonated polyimide foam with balanced surface wettability

Foam-based beds, characterized by their considerable open-pore structures, have demonstrated remarkable efficiency in enhancing the formation dynamics of gas hydrates. However, the relationship between hydration performance and surface wettability of internal pores remains poorly understood. In this work, the sulfonated polyimide (SPI) foams with tunable surface wettability were developed and employed as formation beds for methane hydrates. It demonstrates that the SPI foam with a balanced hydrophobic-hydrophilic surface exhibits a significant enhancement in the formation of methane hydrate. Under static condition, the optimized foam achieves an extremely short induction period and a rapid hydration reaction rate of 2.3 V·V −1 ·min −1 , coupled with a high storage capacity of 119 V/V in water without any chemical additives. The balanced hydrophilic-hydrophobic surface facilitates the construction of hydrogen bonds and hydrate cage nuclei; meanwhile, it reduces interface energy, which promotes the generation and stabilization of hydrogen bond network, leading to rapid hydration reaction. Moreover, it provides a moderate affinity for gas and water, allowing their uniform distribution and thus large contact area, which contributes to a high storage capability. Furthermore, by incorporating super-hydrophobic polytetrafluoroethylene (PTFE) particles into the excessively-hydrophilic SPI foam, a balanced surface wettability is retraced, resulting in efficient formation of methane hydrates. It confirms that the wettability balance between hydrophobicity and hydrophilicity is crucial for efficient gas hydrate formation on a surface. This work provides insights into the influence mechanism of surface wettability on hydrate formation and offers significant guidance for the design of efficient bed reactors in the field of hydrate technology.