Diffusion-charge transfer characterization of a rotating cylinder electrode reactor used for the complete electrocatalytic removal of nitrate from water

Groundwater nitrate contamination is an emerging threat in stressed regions under intensive farming although, lately, efforts to valorize such residues are highly encouraged. Here, electrochemical removal has been investigated as a versatile strategy for this purpose, using reactor equipped with cheap central Fe-based rotating cylinder electrode (RCE) cathode and six concentric Ti|IrO 2 plates anodes. The study of the effect E cath rotational speed ( ω ) on NO 3 − electroreduction from synthetic aqueous solution high conductivity revealed feasibility complete removal, which only required 100-120 min at = -1.80 V vs Hg|Hg SO 4 |sat. K within -range 100-500 rpm. concentration decays agreed perfectly first-order kinetics. NH was accumulated main product, being partly volatilized due quick alkalization, whereas not found. Linear sweep voltammetries demonstrated electrocatalytic activity carbon steel RCE compared inactive stainless steel. Koutecky-Levich analysis showed that reduction process involved 8 electrons. participation H radical mechanism ascertained by electron paramagnetic resonance. mass transport charge transfer were characterized turbulent flow means dimensionless Damköhler Da number, well Sherwood-Reynolds-Schmidt Sh - Re Sc analysis. A mixed regime prevalence control determined -1.8 V. 0.70 0.46 0.356 correlation obtained may serve guide scale-up more materials developed. Successful elimination solutions low mimicked groundwater finally reported. • Rotating enhances Mass C-steel first time Total MSE rpm electroreduction: regime, n e , product future