Experimental Verification of Electroosmotic Dehumidification with Nafion and Plaster-Silica Gel Membranes

In electroosmotic dehumidification, a membrane composed of a desiccant material removes moisture from air to be conditioned. Then, electroosmotic pumping driven by the application of voltage moves the moisture across the membrane and rejects it on the other side. A bench top experiment was developed to screen promising membrane materials. Two sealed humidity chambers were separated by a membrane. The changes in the humidity of the chambers were measured as current was applied to the membrane. The most successful inorganic membrane tested was a silica gel concrete using Plaster of Paris as the cement and silica gel particles as the aggregate. Nafion membranes were also tested and showed a higher current, mass flow rate, and water vapor partial pressure differential. However, the electroosmotic flux is significantly smaller than predicted. Further research is needed to reconcile the experimental data and modeling in order to determine feasibility.