Treatment of Aqueous Solutions Containing Chromium - Experimental Study and Modeling

Abstract

Ultrafiltration is an important technique in the recovery of metal cations from aqueous solutions, this technique is in most cases associated with a complexation reaction, it increases the size of the cations in solution to be retained by the ultrafiltration membrane; in this first part of the work, we are interested only to the effect of pH on the complexation reaction of trivalent chromium by the complexing agent (ethylene diamine tetra-acetate: EDTA), knowing that it is the important parameter in this type of reaction, it can give the percentage of the different species in solution. The second part is devoted to the experimental study of the ultrafiltration of Cr-EDTA complex, carried out in a pilot of ultrafiltration, in order to determine the total transfer resistance of the liquid through the ultrafiltration membrane, this resistance is used for modeling the tangential flow of the Cr-EDTA solution in a tubular membrane for understanding the effect of some parameters (Reynolds and Peclet numbers) on membrane fouling in the treatment of water solutions containing Cr-EDTA complex, using transport equations, Navier-Stokes and continuity; resolution is carried out by the finite volume method, and the results showed that the deposition of solute on the membrane is more important for small Reynolds number values range of 200 to 400 and for large Peclet number valuesin the range of 104 to 105.