Search

Desorption of activated carbon saturated with VOCs (volatile organic compounds) under supercritical CO2 is considered to be a promising method, but the desorption ratio is greatly affected by operating parameters, and the influence mechanism is still ambiguous. In this paper, the influence mechanism of pressure which is the most important operating parameter on the desorption ratio is studied. Toluene is considered as the representative of VOC, the relationship between toluene desorption ratio and pressure is investigated by experimental methods, the diffusion of supercritical CO2 molecules in the nano pores of activated carbon and the interaction between CO2 molecules and toluene molecules are investigated by molecular dynamics simulation. The results show that increasing pressure enhances the interaction energy between CO2 and toluene, which enhances the desorption driving force of toluene. Meanwhile, increasing pressure also reduces the adsorption between activated carbon and toluene, this reduces the desorption resistance of toluene. Finally, the toluene desorption ratio increases as pressure increases. [ABSTRACT FROM AUTHOR]

Desorption of activated carbon saturated with VOCs (volatile organic compounds) under supercritical CO2 is considered to be a promising method, but the desorption ratio is greatly affected by operating parameters, and the influence mechanism is still ambiguous. In this paper, the influence mechanism of pressure which is the most important operating parameter on the desorption ratio is studied. Toluene is considered as the representative of VOC, the relationship between toluene desorption ratio and pressure is investigated by experimental methods, the diffusion of supercritical CO2 molecules in the nano pores of activated carbon and the interaction between CO2 molecules and toluene molecules are investigated by molecular dynamics simulation. The results show that increasing pressure enhances the interaction energy between CO2 and toluene, which enhances the desorption driving force of toluene. Meanwhile, increasing pressure also reduces the adsorption between activated carbon and toluene, this reduces the desorption resistance of toluene. Finally, the toluene desorption ratio increases as pressure increases. [ABSTRACT FROM AUTHOR]

The desorption of activated carbon saturated with VOCs (volatile organic compounds) may not only prolong the life of activated carbon, but also promote environmental protection. Supercritical CO2 is considered to be a promising desorption method because it may avoid the inherent defects of traditional thermal methods. However, the desorption mechanism still remains unclear because the desorption process in the nanopores cannot be observed by the macro-experiments. In this paper, toluene is considered the representative of VOC; the diffusion of CO2, the interaction between CO2 and toluene, and the diffusion of toluene in the nanopore of activated carbon are studied using molecular dynamics simulation. The research results at the molecular level reveal that the strong diffusion of CO2, the interaction energy between CO2 and toluene, and CO2 greatly improving the mobility of toluene play decisive roles for the desorption mechanism. The research results of this paper may provide some beneficial guides for further studying the influence mechanism of VOC types and operating parameters on VOC desorption behavior under supercritical CO2. [ABSTRACT FROM AUTHOR]

The desorption of activated carbon saturated with VOCs (volatile organic compounds) may not only prolong the life of activated carbon, but also promote environmental protection. Supercritical CO2 is considered to be a promising desorption method because it may avoid the inherent defects of traditional thermal methods. However, the desorption mechanism still remains unclear because the desorption process in the nanopores cannot be observed by the macro-experiments. In this paper, toluene is considered the representative of VOC; the diffusion of CO2, the interaction between CO2 and toluene, and the diffusion of toluene in the nanopore of activated carbon are studied using molecular dynamics simulation. The research results at the molecular level reveal that the strong diffusion of CO2, the interaction energy between CO2 and toluene, and CO2 greatly improving the mobility of toluene play decisive roles for the desorption mechanism. The research results of this paper may provide some beneficial guides for further studying the influence mechanism of VOC types and operating parameters on VOC desorption behavior under supercritical CO2. [ABSTRACT FROM AUTHOR]