| Popis: |
We deal with the recovery of chromium from a waste water containing sulfuric acid by both batch and continuous liquid surfactant membrane (LSM) operations, and investigate the proper condition of LSM process, the possibility of recycle use of the organic phase as the liquid membrane phase, and the prediction of the chromium concentration by a proposed transport model. Chromium in the external feed solution was successfully transported and concentrated into the internal stripping solution containing lithium hydroxide through the organic phase of kerosene with 2-ethylhexyl alcohol and polyamine (Exxon Chem., ECA4360J) without any extractant. The recycle of the organic phase did not change the function of LSM, and the continuous operation using mixer-settler type extractors worked as a LSM process together with the developed continuous demulsifier by a.c. high electrostatic field. A model for the chromium transport was presented, in which extraction of chromium, leakage of stripping phase, entrainment of feed phase, and permeation of water were taken into account. The experimental results on the continuous operation were found to be satisfactorily simulated by the proposed model with the experimental parameters from the batch data. |
