| Autor: |
Zhou X; Department of Civil and Environmental 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., Taylor RF; Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., 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., Picioreanu C; Water Desalination and Reuse Center (WDRC), Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia., 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. |
| Abstrakt: |
Low-cost polyamide thin-film composite (TFC) membranes are being explored as alternatives to cation exchange membranes for seawater electrolysis. An optimal membrane should have a low electrical resistance to minimize applied potentials needed for water electrolysis and be able to block chloride ions present in a seawater catholyte from reaching the anode. The largest energy loss associated with a TFC membrane was the Nernstian overpotential of 0.74 V (equivalent to 37 Ω cm 2 at 20 mA cm -2 ), derived from the pH difference between the anolyte and catholyte and not the membrane ohmic overpotential. Based on analysis using electrochemical impedance spectroscopy, the pristine TFC membrane contributed only 5.00 Ω cm 2 to the ohmic resistance. Removing the polyester support layer reduced the resistance by 79% to only 1.04 Ω cm 2 , without altering the salt ion transport between the electrolytes. Enlarging the pore size (∼5 times) in the polyamide active layer minimally impacted counterion transport across the membrane during electrolysis, but it increased the total concentration of chloride transported by 60%. Overall, this study suggests that TFC membranes with thinner but mechanically strong supporting layers and size-selective active layers should reduce energy consumption and the potential for chlorine generation for seawater electrolyzers. |
