Adsorption deformation of a microporous AR-V carbon adsorbent during the adsorption of benzene

Abstract

Adsorption isotherms of benzene and adsorption induced deformation of the AR V microporous carbon adsorbent in the pressure range from 1 Pa to 14 kPa and at temperatures from 255 to 353 K have been determined. Contraction of the AR V adsorbent is observed at temperatures of 333 and 353 K in the low pressure area, which changes into expansion with an increase in pressure. In a low temperature area (255-313 K), only expansion of the AR V adsorbent is observed in the whole range of the studied pressures. The value of the maximal relative compression of the adsorbent changes from 0.18 to 0.08%, while the corre sponding temperature varies from 353 to 333 K. The maximal relative expansion changes from 0.9 to 0.05% along with an increase in the corresponding temperature from 293 to 353 K.

Adsorption-Induced Deformation of Microporous Solids: A New Insight from a Century-Old Theory

“…Note that the stress at the saturation, σ a,0 is The characteristic value of adsorption stress, σ a * = Ea 0 / V 0 , is on the order of 1000 atm, which may result in strain within ∼0.1–1%. For the example of benzene adsorption on AR-V microporous carbon considered below, and σ a * = 0.17 GPa.…”

“…The predictive capabilities of the proposed method are demonstrated based on the experimental data of the adsorption of benzene and n -hexane on the AR-V carbon microporous adsorbent in the range of temperatures from 255 to 353 K. AR-V carbon is produced from coal dust and adhesion agents by steam treatment at 1100 K–1200 K. The experimental adsorption isotherms of benzene and n -hexane at different temperatures in the linear form of the DR equation (log­[ V 0 ] as functions of μ 2 /β 2 (see Figure S3)) collapse into one characteristic curve with the pore volume V 0 = 0.26 cm 3 /g and characteristic energy E 0 = 14.3 kJ/mol for benzene obtained from the fitting of experimental adsorption isotherms; the affinity coefficient β =1.29 for n -hexane is taken from ref .…”

“…Figure presents the universal dimensionless theoretical dependencies of the degree of filling, θ = a / a 0 , for the DR eq and the correspondingly reduced adsorption stress, , eq , as functions of the reduced adsorbate chemical potential, μ/ E , in comparison with the experimental data on benzene and n -hexane on AR-V carbon. calculated with the parameters, E 0 = 14.3 kJ/mol and λ = 0.67, established from the benzene data.…”

“…Lines correspond to the DR characteristic curve (eq ), and the correspondingly reduced stress (eq ). Experimental data on AR-V carbon for (A) benzene and (B) n -hexane at 353 K (black), 333 K (brown), 313 K (red), 293 K (blue), 273 K (green), and 255 K (purple). The circle symbols correspond to adsorption and square symbols to the desorption data.…”

“…a a l , eq 15, as functions of the reduced adsorbate chemical potential, μ/E, in comparison with the experimental data on benzene 33 and n-hexane 34 on AR-V carbon. σ a calculated with the parameters, E 0 = 14.3 kJ/mol and λ = 0.67, established from the benzene data.…”