Transport of the biological membranes process to the treatments of low-grade metal effluents Transport, counter-transport, positive coupling Original Research Article

An ionic pump has been devised thanks to a liquid-liquid extraction-reextraction where the extraction compartment and the reextraction compartment are put in contact with one another through the membrane composed of a mediator diluted in kerosene. We have applied this process to the system: uranyle nitrate, nitric acid, tri-n-octyl phosphine oxyde, kerosene-sodium carbonate. Interesting results have been obtained for diluted solutions (100 ppm). The chemical parameters were adjusted to find the variables that produced the extraction and reextraction efficiency optimum. A chemical model has enabled the transfer mechanism to be identified. The classical behavior obtained in agitated surroundings has been found again. For the extraction compartment, the competition of nitric acid has been found. The membrane can work thanks to the activation by the solute of the carrier at one interface and to the deactivation at the other interface, both of these mechanisms of the active transport creating real ionic pumping. We are in presence of an active transport, counter-transport, positive coupling.