Fig. 2: Nitrate reduction performance on EMs.
a The single-pass filtration assembly used to conduct all the electrochemical experiments. b Removal of nitrate on EMs with different pore diameters. The dotted lines represent the pseudo-first-order kinetic regression curves (R2 > 0.99). c Pseudo-first-order kinetic constants of nitrate reduction on the EMs at concentrations of 0.1, 1, and 10 mM. d Contributions of direct electron transfer (DET) and indirect electron transfer mediated by H* to the reaction kinetics. e Distribution of nitrogen species in the permeate (left axis) and NH4+ selectivity (right axis) on the EMs at a hydraulic residence time (HRTgeom) of 55 s. f FEs for nitrate reduction on the EMs at HRTgeom values of 3 and 27 s. Nitrate concentration: 1 mM. g Energy consumption for nitrate reduction on the EMs. Eelectrical and Epumping represent the electrical and pumping energy, respectively. h Long-term nitrate reduction stability test of EM7 with 1 mM nitrate at an HRTgeom of 91 s. Current density: 39.3 mA cm−2, reaction conditions: 0.1 M Na2SO4, pH = 7. Error bars represent the standard deviation from at least two independent tests.
