Phenomenological Comparison of Vacuum Membrane Distillation for VOC Removal and Desalination

Abstract

Vacuum Membrane Distillation (VMD) is a separation process applied to liquid solutions; however, there are phenomenological and operational differences depending on whether the component to be separated is the solute or the solvent. The objective of this article is to develop a mathematical and phenomenological model of the VMD process applied to the separation of volatile organic compound (VOCs) from aqueous solutions and the desalination of saline aqueous solutions. This approach enabled the evaluation of the influence of variables and operating conditions on both separation efficiency and system productivity. Under the analyzed conditions, increasing the temperature, flow rate, and vacuum pressure led to approximate increases in permeate flux of 400%, 10%, and 50%, respectively. In the case of concentration increase, the permeate flux increases linearly for VOC separation and decreases asymptotically for saline solution desalination. Therefore, adjusting the feed temperature is recommended to achieve significant changes in permeate flux.