Comparative study of moisture transfer of polyethersulfone-based membranes and kraft paper

Abstract

The efficiency of membrane-based enthalpy exchangers primarily depends on the moisture permeability of the membranes used. While traditional kraft paper membranes exhibit favorable moisture adsorption properties, they lack durability and are prone to bacterial growth. To overcome these limitations, alternative membrane materials, including polyethersulfone (PES) film, asymmetric porous PES membrane (P-MEM), and composite membrane (C-MEM) comprising PES and polyether block amide (PEBAX), have been investigated. These membranes' physical properties and water adsorption affinity were compared with that of conventional kraft paper. Experimental measurements of moisture permeation and adsorption equilibrium were conducted to evaluate the moisture transfer properties of the membranes under different operating conditions. The experimental and modeling results showed that the moisture transfer resistance of the membranes varied depending on the material and temperature, with a lower degree of dependence on the surrounding fluid humidity. C-MEM exhibited the highest moisture resistance, followed by kraft paper, while P-MEM and PES had the lowest resistance. Additionally, the moisture diffusivity and activation energies for moisture transport were determined for each membrane.