This thesis presents an original approach for the concentration of thermo-sensitive solutions: the Sweep Gas Membrane Distillation (SGMD) process. A new membrane contactor with metallic hollow fibers has been designed and allows the distillation process to be operational at low temperature. Heat is generated in the fibers by the Joule effect, rather than being supplied as latent heat in the liquid bulk. The localized generation of heat results in a reduction of temperature polarization phenomena. The stainless-steel hollow fiber membranes have been synthetized with appropriate structural properties and sufficient mechanical strength. The pore surface of the fibers has been made hydrophobic by the deposition of a thin layer of an elastomer. Moreover, a novel and green method is presented to fabricate alumina and stainless-steel hollow fibers. This method is based on ionic gelation of a biopolymer and completely avoids the use of harmful solvents. By a detailed experimental study of the SGMD the influence of different operational parameters on the process performance has been investigated. The improvements in the flux and the separation efficiency using Joule effect have been successfully demonstrated, even in the case of pervaporation.
|Award date||18 Dec 2014|
|Publication status||Published - 18 Dec 2014|