HOLLOW-FIBER SUPPORTED LIQUID MEMBRANE PROCESS FOR THE SEPARATION OF NH3 FROM AQUEOUS-MEDIA CONTAINING NH3 AND CO2

A hollow fiber supported liquid membrane (SLM) process was investigate d experimentally and theoretically for the separation of NH3 from aque ous solutions containing NH3 and CO2. DTPA and D2EHPA were used as car riers and n-decanol was used as a diluent in this process. The membran e stripping experiments, as well as the extractive equilibrium experim ents, indicate that DTPA is a better carrier than D2EHPA in relation t o the increase in the NH3 stripping rate. The influence of operating c onditions, such as flow rate, the ratio of NH3 to CO2, and carrier con centration, on the membrane stripping rate were examined. The experime ntal data demonstrate that the NH3 stripping rate by an SLM process is not significantly influenced by the amount of CO2 present, as is that by the supported gas membrane. To predict the stripping of NH3 from s olutions containing NH3 and CO2, a mathematical model incorporating ch emical equilibria and Nernst-Planck diffusion was developed to describ e the mass transport. The experimental data suggested that the SLM pro cess can effectively strip NH3 from aqueous solutions containing NH3 a nd CO2.