The behaviour of Nafion® 424 membrane in the electrochemical production of lithium hydroxide

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Abstract
BACKGROUND: Nafion® membranes have found several applications in chemical processes, one of which is ‘salt splitting’, where a salt is split to produce acid and/or alkali. So, the determination of the behaviour of this membrane in the electrolysis of certain salts is an important issue. The aim of this study is to investigate the performance of Nafion® 424 membrane in a two‐compartment membrane cell for the membrane electrolysis of lithium sulphate (Li2SO4), where lithium hydroxide (LiOH) is the target product.RESULTS: Regression analysis was performed between conductivity and concentration to predict instantaneous electrolyte concentration. The effects of catholyte concentration (4–8% LiOH), current density (4–16 A dm−2) and temperature (30–60 °C) were investigated. 45–70% current efficiency; 6.1–14.6 kWh kg−1 LiOH power consumption and 140–900 g LiOH m−2 membrane h−1 production rate were obtained. A cost estimation revealed that 60 °C, 8% LiOH and 4 A dm−2 are the optimum parameters within the studied range.CONCLUSION: Concentration can be successfully predicted for lithium sulphate and lithium hydroxide with the help of conductivity–concentration regression equations. Current efficiency is affected primarily by LiOH concentration with a direct proportion. Power consumption increases with the increase of current density and the decrease of temperature. Based on production cost estimation, optimum working parameters can be recommended. © 2015 Society of Chemical Industry
Funding Information
  • TUBITAK SAVTAG (111A016)