Improved Carbon Dioxide Hydrate Formation Using Superabsorbent Polymers (SAPs) and Tetrahydrofuran (THF) Without Mechanical Agitation

Abstract

Clathrate hydrates are ice-like crystalline compounds formed by 3-dimensional network of hydrogen bonding of water molecules, which can store small guest molecules such as hydrogen or methane inside their cavities. With this unique property, the clathrate hydrates had been studied for gas storage and separation. However, greenhouse gas capture by formation of carbon dioxide hydrate is still challenging, due to its low storage capacity despite of using surfactants such as sodium dodecyl sulfate (SDS). Here, we combined tetrahydrofuran (THF) and superabsorbent polymers (SAPs) for improving carbon dioxide hydrate formation without mechanical agitation, which showed excellent performances for methane hydrate formation in a previous study.1 The storage capacity, and induction time of CO­2 hydrate formation were studied according to molar concentration of THF, and these results were compared with cases in the absence of SAPs. Also, scaled-up experiments were conducted for designing feasible hydrate-based carbon capture process. Finally, Raman and PXRD spectroscopic analyses were conducted to confirm whether ‘tuning phenomena’ occurred below the stoichiometric concentration of THF.