Adsorption of gaseous molecule within polyfluorinated surfactant/saponite hybrid compound Original Research Article

Adsorption behavior of gaseous molecules such as water vapor, nitrogen, and hydrogen within the interlayer of the hybrid compound composed of cationic polufluorinated surfactant, heptafluorobutanoylaminoethylhexadecyldimethylammonium bromide (C3F-S), and cation exchangeable clay, saponite, was studied by means of quartz crystal microbalance (QCM). The amount of adsorption of the gaseous molecules proportionally increased with the increase of the intercalated amount of C3F-S within the inorganic/organic hybrid compound. When the hybrid compound was dried before the gaseous adsorption, the dynamic response of the adsorption was very fast within 1 s, while it required a long time for ca. 10 h to plateau to a saturation level after an initial rapid increase followed by a slow decay of the QCM signal for the wet sample containing water (0.3 mmol/g-saponite). The dried hybrid compound, having C3F-S in the amount 4.3 equiv. against cation exchange capacity, adsorbed nitrogen (0.03 mmol/g-saponite), hydrogen (0.1 mmol/g-saponite), oxygen (0.03 mmol/g-saponite), ethylene (0.19 mmol/g-saponite) at 298 K, 101 kPa, respectively. The wet sample exhibited the gaseous adsorption with the larger amount: nitrogen (0.068 mmol/g-saponite), hydrogen (0.4 mmol/g-saponite), oxygen (0.067 mmol/g-saponite), and ethylene (0.24 mmol/g-saponite), respectively.