Dehydration through pervaporation from HIx solution (HI-H_2O-I_2 mixture) using a cation exchange membrane for thermochemical water-splitting iodine-sulfur process

摘要

Pervaporation (PV) of water from HIx solution (HI-H_2O-I_2 mixture) using Nafion-117 was evaluated aiming at the application to dehydrate the azeotropic composition in HI decomposition reaction of thermochemical IS process. PV experiment was carried out by using HI solutions of 40-65 wt% and an I_2/HI molar ratio of 0-3 in the feed at the room temperature. The permeation flux decreased with increasing HI weight fraction in the feed. The permeation flux is dependent on the I_2 concentration in the feed having an I_2/HI molar ratio. A long time PV experiment was carried out using I_2/HI molar ratio of 1 (in HI solution of 55.9%) in the feed at room temperature. It is expected that the permeation component in the permeate zone using the PV process was mainly H_2O, and H_2O permeation was constant with increasing operation time.