Equilibrium and thermodynamic study of trichloroethylene adsorption on activated carbon in a fluidized bed and its thermal regeneration

Abstract

Volatile organic compounds (VOC), used as solvents in industries, are major sources of air pollution. Trichloroethylene (TCE) is a chlorinated VOC widely used in industries. TCE vapours are toxic in nature and adversely affect human health and the surrounding environment when exposed over the threshold limit value for a long duration. Adsorption of TCE vapours using activated carbon as an adsorbent in a fluidized bed and its thermal regeneration is a viable, effective, and economic technology for its separation from air. However, before designing such a system, the equilibrium and thermodynamic study of the adsorption of TCE vapour on activated carbon is important. In this study, the dynamic adsorption of TCE vapour was carried out in a fluidized bed using nitrogen as the carrier gas. The effect of operating conditions, including particle size of activated carbon (212–710 μm), flowrate of nitrogen (carrier gas), adsorption temperature (303–353 K), and the concentration of TCE vapour in nitrogen at the inlet (25–85 mg/L) on the adsorption capacity of TCE on the fluidized bed of activated carbon, was examined. The experimental results obtained were analyzed using the Langmuir and Freundlich adsorption isotherms. The thermodynamic study showed that the adsorption of TCE was spontaneous, exothermic, and physical in nature. The effect of regeneration temperature and purge gas flowrate on the renewal of used activated carbon was also studied.