Reducing Chloride Ion Permeation during Seawater Electrolysis Using Double-Polyamide Thin-Film Composite Membranes.

Autor:	Zhou X; Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Taylor RF; Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Shi L; Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.; College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, P. R. China., Xie C; Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Bian B; Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Logan BE; Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.; Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Jazyk:	angličtina
Zdroj:	Environmental science & technology [Environ Sci Technol] 2024 Jan 09; Vol. 58 (1), pp. 391-399. Date of Electronic Publication: 2023 Dec 26.
DOI:	10.1021/acs.est.3c07248
Abstrakt:	Low-cost polyamide thin-film composite membranes are being explored as alternatives to expensive cation exchange membranes for seawater electrolysis. However, transport of chloride from seawater to the anode chamber must be reduced to minimize the production of chlorine gas. A double-polyamide composite structure was created that reduced the level of chloride transport. Adding five polyamide layers on the back of a conventional polyamide composite membrane reduced the chloride ion transport by 53% and did not increase the applied voltage. Decreased chloride permeation was attributed to enhanced electrostatic and steric repulsion created by the new polyamide layers. Charge was balanced through increased sodium ion transport (52%) from the anolyte to the catholyte rather than through a change in the transport of protons and hydroxides. As a result, the Nernstian loss arising from the pH difference between the anolyte and catholyte remained relatively constant during electrolysis despite membrane modifications. This lack of a change in pH showed that transport of protons and hydroxides during electrolysis was independent of salt ion transport. Therefore, only sodium ion transport could compensate for the reduction of chloride flux to maintain the set current. Overall, these results prove the feasibility of using a double-polyamide structure to control chloride permeation during seawater electrolysis without sacrificing energy consumption.
Databáze:	MEDLINE
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