Fig. 4: Inhibitory ion transport.

a Measured fluxes of Ba²⁺ and Pb²⁺ versus the concentration of Pb²⁺ in the feed in the series of Ba²⁺/Pb²⁺ pair permeation tests across one Pb²⁺-locked MoS₂-COOH membrane. b Measured fluxes of Co²⁺ and Pb²⁺ versus the concentration of Pb²⁺ in the feed in the series of Co²⁺/Pb²⁺ pair permeation tests across one Pb²⁺-locked MoS₂-COOH membrane. In (a) and (b), both the ion fluxes are normalized to values corresponding to the initial Ba²⁺ test and Co²⁺ test, respectively. Data: mean ± standard error. The dashed lines are used for visual guides. c Calculated diffusion coefficients of Co⁺, mobile Pb²⁺ and Cl^– throughout the MD simulations. d Probability of ions passing through the channel. Solid lines and dashed lines represent Co²⁺/Pb²⁺ and K⁺/Pb²⁺ tests, respectively. Data is presented as mean ± standard error, based on three independent MD simulations. e Schematic of the passage for single divalent ion transport. f Schematic of competition for the passage for binary divalent ion transport.