Copper removal from ammoniacal wastewater through a hollow fiber supported liquid membrane system: Modeling and experimental verification

Detailed theoretical mechanism of facilitated Cu(II) transport from ammoniacal wastewater through hollow fiber supported liquid membrane (HFSLM) system based on the “Big Carrousel” mechanism is first time developed in this work. According to this mechanism the carrier is able to diffuse from the organic membrane phase into the thin aqueous reaction layers where ion exchange reactions are taking place. Experimental results demonstrate that the overall mass transfer resistance through HFSLM is higher than total of the element resistances in the tube side, shell side and the membrane, estimated based on the empirical correlations. It reveals that the overall mass transfer resistance also depends on the parameters of chemical reaction in the aqueous reaction layers, corresponding to the “Big Carrousel” mechanism. In the case of copper transport from ammoniacal solutions, this factor was usually neglected. The resistances developed in the aqueous reaction layers become important because the copper–ammonia complexes are very stable and their reaction with the carrier cannot be considered fast in comparison to the elementary transport processes and cannot be neglected.