Preparation of porous membrane for moisture absorption from high‐humidity gases

Abstract

Suitable air humidity is of great importance for human health, crop growth and the life of buildings. In this work, the polyvinylidene fluoride/calcium chloride (PVDF/CaCl2) porous membranes with rich pore structures for adsorption of high‐humidity gases were prepared using solvent evaporation‐induced phase separation. The results showed that the gap between the PVDF spherical crystals increased with the increase of CaCl2 content, which increased the porosity of the membrane. When the CaCl2 content reached 20 wt.%, the water vapor adsorption capacity of the PVDF/CaCl2 porous membrane was 0.876 and the initial adsorption rate was 0.050 g·g−1·min−1. At this point, the moisture vapor permeance of the membrane was the best at 0.04 g·m−2·h−1·Pa−1, and the dry strength of the PVDF/CaCl2 membrane was 0.397 MPa, which was 1.64 times that of the membrane without CaCl2. This work provides theoretical and technical guidance for the preparation of air dehumidification materials.Highlights The porosity of the membranes increased with increasing of calcium chloride content. The moisture vapor permeance of the M‐20 membrane was the best at 0.04 g·m−2·h−1·Pa−1. The dry strength of the M‐20 membrane was 1.64 times that of the M‐0 membrane.