Ammonia adsorption in a fixed bed of activated carbon

Abstract

The rise in atmospheric pollution caused by gases such as ammonia has led many researchers to conduct studies aimed at decreasing or treating the emissions of such polluting gases. The present work attempted to study the adsorption of ammonia in the fixed bed of activated carbon as a means to treat its emissions. The effects of the initial concentration of ammonia ( C 0) and of the bed temperature ( T L) on the adsorption of ammonia by the activated carbon were also considered. Adsorption capacity of activated carbon was determined using data from the breakthrough curves and from a balance of mass in the bed. Adsorption capacities were obtained employing the Langmuir and Freudlich isotherms. The results showed that within the NH 3 concentration range of 600–2400 ppm, adsorption capacity varied from 0.6 to 1.8 mg NH 3/g carbon at 40 °C, from 0.2 to 0.7 mg NH 3/g carbon at 80 °C and from 0.15 to 0.35 mg NH 3/g carbon at 120 °C. These numbers highlight the tendency toward a lower adsorption capacity with the decrease in temperature. As to mass of the bed, this latter variable had no significant influence over adsorption capacity.