Electrochemical and hydraulic analysis of thin-film composite and cellulose triacetate membranes for seawater electrolysis applications

Polymeric filtration membranes could be a cost-effective alternative to cation exchange (CEMs) in electrolysis with contained anolyte and saltwater catholyte because they size selectively hinder salt ion transport between compartments while facilitating proton hydroxide transport. Optimizing membrane performance requires better understanding of properties that impact electrical resistances retention. Twelve reverse osmosis (RO) membranes, one nanofiltration (NF) membrane, cellulose triacetate forward (FO) were examined for their under conditions typically used characterization CEMs. Resistances measured at low current densities (0.07–0.3 mA cm−2) varied different by over an order magnitude 1 M NaCl neutral pH, from 6.1 ± 0.1 Ω cm2 70 30 cm2. There was no significant correlation resistance applied potential during 20 cm−2 (p = 0.44), or water permeability 0.35). These results indicate traditional CEM methods do not predict polymeric transport, which is important when large pH gradients develop, must considered separately molecule through selective RO, NF, FO electrolysis.