Adsorption isotherms and kinetics of a mixture of Pentafluoroethane, 1,1,1,2-Tetrafluoroethane and Difluoromethane (HFC-407C) onto granular activated carbon

Adsorption of fluorinated greenhouse gases on activated carbons: evaluation of their potential for gas separation

“…This work aims to study the capture by adsorption of the three most commonly employed pure F‐gases in domestic refrigeration (R‐32, R‐125, and R‐134a). The adsorption of these gases on activated carbons (ACs), zeolites, or metal–organic frameworks (MOFs) at various temperature and pressure ranges has been reported in the literature . Even though MOFs present in general higher adsorption capacities, ACs are the most commonly used adsorbents in many industrial processes due to their large micropore and mesopore volumes, high surface area, variety of surface functional groups, low cost, and wide range of available morphologies …”

“…The adsorption of R‐32, R‐125, R‐134a, and of commercial refrigerants containing these F‐gases on other ACs has been already studied in the literature. However, to the best of our knowledge, this work is the first publication reporting on a systematic study of the adsorption of those three pure F‐gases on four different ACs with different porous characteristics in order to select the best material for the separation of commercial refrigerants.…”

“…Furthermore, both AC1 and AC2 have been previously characterized and the latter has also been studied before for gas adsorption and separation. [32][33][34] The adsorption of R-32, 10,26 R-125, 24,25 R-134a, [14][15][16][17]19,20,[27][28][29] and of commercial refrigerants containing these F-gases 30,31 on other ACs has been already studied in the literature. However, to the best of our knowledge, this work is the first publication reporting on a systematic study of the adsorption of those three pure Fgases on four different ACs with different porous characteristics in order to select the best material for the separation of commercial refrigerants.…”

Variable diffusivity homogeneous surface diffusion model and analysis of merits and fallacies of simplified adsorption kinetics equations

“…This condition implies constant fluid phase concentration and is often overlooked in literature. For instance, it has been applied for the sorption of Cu 2+ on hydroxyapatite and zeolite [58], several heavy metals on zeolite [59], and freon on activated carbon [60] under finite solution volume conditions.…”

“…This model is not as common as other adsorption diffusion-based models in literature, but it has been applied in a number of systems, such as for the ion exchange of nickel and zinc on Amberlite IR-120 resin [81]. Glueckauf's equation with g=15 and Vermeulen's equation were successfully applied by El-sharkawy et al [60] on the kinetics of a mixture of pentafluoroethane, 1,1,1,2-tetrafluoroethane, and difluoromethane onto granular activated carbon. Jribi et al [82] studied the adsorption of CO2 on activated carbon and found that the LDF equation with a constant mass transfer coefficient cannot fit the experimental data.…”