Fabrication of a lithium chloride solution based composite supported liquid membrane and its moisture permeation analysis

A novel composite supported liquid membrane has been prepared for ventilation air moisture recovery. The membrane is composed of three layers: two hydrophobic protective layers and a sandwiched hydrophilic support layer in which LiCl solution is immobilized to facilitate water vapor transfer. A test is conducted to measure the moisture permeation rate through the composite membrane. Various resistances in the cell and in the composite membrane are clarified. Linear equilibrium relations between humidity, temperature, and LiCl concentration in the liquid solution layer are obtained to aid in the model set-up. It has been found that the mean moisture permeation rate through the composite membrane is around 1.14 × 10−4 kg m−2 s−1, almost two times higher than that through a solid hydrophilic cellulose acetate membrane with comparative thickness. Further, the supported liquid layer only accounts for 12% of the total moisture transfer resistance in the cell, indicating that there is much potential for further performance improvement.