Super Activity of ACS Carbon Adsorbent in n-Butane Adsorption

摘要

? 2022, Pleiades Publishing, Ltd.Abstract—: Adsorption of n-butane onto ACS microporous carbon adsorbent with a wide pore-size distribution was studied at a pressure as high as 0.25 MPa and the temperatures of 303, 313, 323, and 333 K. The specific volume of micropores of the adsorbent was 2.00 cm3/g. ACS adsorbent had a bimodal pore-size distribution, with the effective pore sizes of 1.42 and 3.8 nm. At a temperature of 303 K and pressure of 0.231?MPa, the maximum value of n-butane adsorption reached 18.62 mmol/g. The BET specific surface was SBET?=?2560 m2/g. The initial differential molar heat of adsorption of n-butane onto ACS adsorbent was found to be 29.1 kJ/mol. The differential molar heats of adsorption of n-butane onto ACS adsorbent weakly depended on temperature and passed through a maximum of ~30 kJ/mol at the adsorption value of ~12?mmol/g. A further increase in the value of n-butane adsorption up to 16 mmol/g led to a drop in the heat of adsorption to ~25 kJ/mol. The isotherms of n-butane adsorption were described using the two-term equation of the theory of volume filling of micropores (TVFM). It was found that the bimodal equation of the TVFM well described the n-butane adsorption using the structure and energy parameters of the adsorbent determined from the data on adsorption of benzene and nitrogen vapors throughout the entire ranges of temperatures and pressures.