Abstract
Gaseous ammonia and amines are commonly generated in various chemical processes, fermentation processes, waste treatment processes, and so on. Because of their strong smell, removal of these gases is very important. Most studies in the field of adsorption deals with the search for new adsorbent materials as well as improvement of the existing adsorbents. In the present study, a new adsorbent was developed by impregnating humic acid into an activated carbon. Humic acid can be produced economically from either the waste materials of animals or plant remains. Humic acid has a number of carboxyl groups which are acid functional units. Thus, high selectivity is expected when basic substances are adsorbed onto this type of impregnated adsorbent. Humic acid impregnated activated carbon (GA/humic acid) was prepared by inactivating humic acid in a pore of the original activated carbon (GA4-8) with sulfuric acid. From the pore size distribution of GA/humic acid measured with a mercury porosimeter and an automatic surface analyzer, it becomes clear that humic acid localizes in the macropore of GA4-8. The equilibrium isotherms for adsorption of NH3 on GA4-8, and GA/humic acid were derived from the breakthrough curve experiments. The adsorption of NH3 on GA/humic acid substantially increased more than 3 times higher than the capacity of GA4-8. Humidity did not affect the amount of NH3 adsorbed. The effective intraparticle diffusivities were determined by fitting the mathematical model proposed in the previous study with the experimental breakthrough curves. Effective intraparticle diffusivity became small with increasing of concentration of humic acid impregnated. Humidity did not affect the effective intraparticle diffusivity of NH3 in GA/humic acid but affected in GA4-8.
