Membrane-based detection of wetting phenomenon in direct contact membrane distillation

Abstract

Advances in membrane distillation are limited by the wetting phenomenon. Wetting is typically determined by examining the permeate water quality. In this work, we apply an electrically conductive membrane to direct contact membrane distillation combined with an electrochemical system. The membrane was fabricated by heat pressing a carbon cloth with electrospun PVDF-HFP mat. The membrane acts not only as a barrier to reject salt with 99.6% rejection, but also as an electrode where in the current through the system is used to detect wetting which allows Na+ and Cl− ions to complete the cell. It was found that the membrane has an LEP of 36psi and mean pore size of 0.2µm. A continuous voltage of +1V was applied during the direct contact membrane distillation process, and a sharp increase in current was observed at the point where wetting was induced.