Each membrane was preconditioned immediately before use in separation experiments to ensure steady performance, as recommended by the manufacturer . Preconditioning removes preservatives and impurities from the membrane and reduces the influence of membrane compaction effects on experimental results. For preconditioning a fresh piece of BW30 membrane was installed in the HP4750 stirred cell and run at 30 bar pressure under a purified deionized water feed until the permeate flux stabilised. The permeate flux was monitored through automated recording of the cumulative permeate weight at 60 s intervals. The transmembrane flux of pure water across BW30 stabilised after roughly 90 min, reaching an average steady state value of 𝐽 !(/01),'' = 17 ∓ 2 𝑚𝑙 𝑚 40 𝑠 45 (SI Section S2). Once preconditioning was completed, the cell was emptied of residual water and, to prevent the membrane from drying out, immediately refilled with feed solution.