Preparation of the SPES Dense Membrane and Its Application in Membrane Dehumidification

Sulfonated poly(ether sulfone) (SPES) has high water vapor permeability and selectivity, and permeability is a key characteristic that determines the dehumidification performance. The excellent properties of SPES make it a favorable competitor for dehumidification materials. In order to obtain SPES, PES must be sulfonated. The effect of the degree of sulfonation on the structure and properties of SPES dense membranes manufactured by the solvent evaporation method was studied, and the prepared membranes with different degrees of sulfonation were applied in the dehumidification process to investigate the effect of the degree of sulfonation on the dehumidification performance. The results show that the hydrophilicity (contact angle and water absorption) of the SPES dense membrane is stronger with the higher degree of sulfonation. On the other hand, the mechanical strength of SPES membranes showed the opposite trend, because the polymer degraded during the sulfonation reaction, contributing to a decrease in the mechanical strength of SPES membranes. During the dehumidification process, the dehumidification performance of SPES membranes was significantly improved with the increase of the sulfonation degree, and the dehumidification efficiency and water vapor permeation flux of the 50% SPES dense membrane were the best, which were 42.8% and 13.4 × 10–6 kg·m–2·h–1, respectively.