Removal of NO3- is a challenging problem in wastewater treatment. Electrocatalysis shows a great potential to remove NO3- but selectively converting NO3- to N2 is facing a low efficiency. Here, a novel 3D Pd-Cu(OH)2/CF cathode based electrocatalytic (EC) system was proposed that can rapidly and selectively convert NO3- to NH4+, and further convert to N2 simultaneously. The special designs for the system include: Cu(OH)2 nanowires were firstly grown on copper foam (CF) with excellent conductivity that features high specific surface area in enhancing NO3- absorption and conversion to NO2-. Then, palladium (Pd) with a superior photons activation capacity was doped on the Cu(OH)2 nanowires to promote the reduction of NO2- to NH4+. Then NH4+ was quickly oxidized into N2 by active chlorine. Finally, total nitrogen (TN) could easily be removed completely via above exhaustive cycle reactions. The 3D Pd-Cu(OH)2/CF cathode exhibits a 98.8 % conversion of NO3- to NH4+ in 45 min with the reported highest removal rate of 0.017 cm-2 min-1, which is 19.4 times higher than that of CF. The converted NH4+ was finally exhaustively oxidized to N2 with a 98.7 % of TN removal in 60 min.
Keywords: Cathode; Electrocatalytic system; Nitrogen; Pd-Cu(OH)(2) nanowires.
Copyright © 2020 Elsevier B.V. All rights reserved.