HOLLOW-FIBER GAS-MEMBRANE PROCESS FOR REMOVAL OF NH3 FROM SOLUTION OFNH3 AND CO2

A hollow-fiber supported gas membrane process for the separation of NH 3 from aqueous solutions containing both NH3 and CO2 was investigated theoretically and experimentally. A lumen laminar flow and radial diff usion model was applied to calculate the membrane wall transfer coeffi cient from the data stripping a single volatile component, NH3 or CO2, from their individual aqueous solutions. Influence of the type of mem branes and operating conditions on mass-transfer rate were discussed, especially the influence of the membrane transfer coefficient on the f ilm mass-transfer coefficient in the lumen. Appropriate configurations of the hollow-fiber modules for stripping of a single component were analyzed to optimize mass transfer. To predict the stripping of NH3 fr om a solution containing NH3 and CO2, a mathematical model incorporati ng local chemical equilibria and Nernst - Planck diffusion was develop ed to describe the mass transport. The models described the experiment al data fairly well. The experimental results showed that the supporte d gas membrane process can be used to remove NH3 effectively from aque ous media containing NH3 and CO2.